Open Roads Forum

Print  |  Close

Topic: Refrigerator fan mods that worked for me with pics

Posted By: nycsteve on 07/31/11 04:45pm

Last year in May I went down to the Florida Keys. The temperatures were in the low to mid 90’s. Where I was parked the fridge was in the shade at least half the day. Even so within the week the fridge started not being able to hold temperature. It was a slippry slope. The temps in the fridge rose to the point it was 50 degrees in the lower and just barly freezing in the freezer with very soft ice cream. There was no bounce back at night during colder temps. It was past the point of no return. I have a NORCOLD absorbtion refrigerator built in 2007. It is contained in the slideout room and has side wall vents .
[image]

To try and avoid a repeat of this I read up on causes and possible solutions. There are a few different design fans available. Before a trip out west last August I installed this fan
[image]
Which is seen in the lower right . The theory is that it will blow cold air up onto the hot frige coils and in coolng them enabling the fridge to operate even as it heats up. The limiting factor with an absorbtion fridge is the hotter the coils in the back get the less its able to cool the inside of the fridge. Which can knock out the unit when you need it most, in hot weather. This fan was made by Valterra and was purchased for less than 20 dollars. It has a thermostat and an on /off switch, and wired into the 12v wires behind the fridge accessable behind the loer wall vent. It helped but I thought more was needed.
This spring , before a July trip to the Keys I installed the following
First is this fan which clips (the clip acts as the ground) to the fins in the interior of the fridge

[image]

It was purchased on EBAY for 18 dollars delivered. The claims are , no frost on the fins resulting in better effeciancy. This is true, there was little to no frost buildup after 30 days in the hot Florida sun this past late June to July. In hot weather the fridge maintained temp 2 settings below its traditional setting. Wiring was not hard. On NORCOLD fridges older than 2007 the one positive wire goes directly into the hot in the interior fridge light. In my 2007 model there is no continuous hot in the light. Following the sellers directions, with pictures, I ran a 20g wire through the excess water hose in the water tray inside the frige which leads to a water tray in the back. I relocated the tray and wired to the same hot the back fan used. I also added an on/off switch visable in the first pic attatched to the fridge shelf.
Heres a pic of the wire coming out of the water tube in the back

[image]
To find the EBAY seller for this do a search on EBAY for RV refridgerator fans. You’ll see it.
Further I added a fan at the top of the fridge rear behind the top vent on the theory it would draw and expel hot air building behind the unit. It was screwed into the sheetmetal at the top

[image]

With its own on/off switch

[image]

This was purchased from AMAZON for 35 dollars delivered. It was also a VALTERRA product. It pushes a lot of air. It came with an inline thermostat which was non functional. The on/off switch works well (purchased seperatly from a hardware store)
Results and conclusions.
The fridge held temps throughout the Keys trip this year. While I feel all the modifications worked together to make this possible, the strongest performer was the fan at the top of the frige on the outside. It really helped to exhaust the hotair buildup.
Second most effective was the interior blue fan on the fins. It circulated the interior air and helped the fridge cool.
Also I added a digital thermometer on the fridge which gave accurate freezer and lower box temp readings and kept a record of the high and low readings. I was able to monitor the temps without opening the doors .
Also a stragedy of adding beverage bottles to cool in the evening after the frige got a handle on things rather than stressing the fridge by adding warm bottles at the peak heat times during the day helped.
Temps never rose above 40 in the upper box and 5 in the freezer. Most times temps were lower than this even on lower settings. I found myself backing off to a level 6 at night and 7 in the day, a vast improvement over last year when a top setting of 9 still failed.
These mods worked out very well for me in a high temp / hot sun Florida environment this past month. Just my experience.
All mods together came to less than 100.00 and were easy to install.






Posted By: FF1063 on 07/31/11 05:14pm

######

* This post was edited 09/25/11 07:59pm by FF1063 *


Posted By: Gale Hawkins on 07/31/11 11:21pm

ng2951 wrote:

I am not sure if the interior fan is a great idea. The motors add heat in the box too. So the question is do they improve the heat removal process more than they contribute.

Certainly the exterior fan should help a lot...


While we have not added the inside fan mod I have pulled several fin temperature readings over a period of time. The coolest spot on the fins will consistently measure 10-12F degrees cooler than air temps within 6-8" of the fins.

Based on this info it should make the fins more effective at removing heat from the lower box.


Posted By: ng2951 on 07/31/11 10:36pm

I am not sure if the interior fan is a great idea. The motors add heat in the box too. So the question is do they improve the heat removal process more than they contribute.

Certainly the exterior fan should help a lot...


Foard County News & Sassy Schoolmarm
with Chloe, Belle, & Danke
2017 GD Imagine 2800BH
2017 53 days camping
'07 GMC Sierra 2500HD Classic 4x4 LBZ Duramax Diesel
Honda 2000sThe Bayou Bounty Hunters Cowboy Club
The Single Action Shooting Society


Posted By: Bigfootchevy on 07/31/11 06:00pm

Great information and pics. There is never any shortage of ideas on this site. Thanks for sharing.

Paul


Posted By: sleepy on 07/31/11 06:09pm

Good post, thanks for sharing.

I hadn't seen these products,,, most of us have tried jury rigs with varying degrees of success.

I always wanted one of those solar fan fridge vent covers for the roof of my camper until I realized that it would do nothing but impede the air flow on hot nights,,, no sun.

Time to google...


2003 Lance 1161,/slideout/AGM batteries/255W Solar/propane generator/Sat dish/2 Fantastic Fans/AC/winter pkg
AirFoil, Trimetric, LED lights, Platcat vent heat

2003GMC K3500 LT/Crewcab/duramax diesel/allison/dually/4x4/OnStar/front reciever mounted spare


Posted By: joe b. on 08/01/11 06:02am

Thanks Steve, I am currently dealing with the same problem. Am on the return trip from Alaska to Florida, where we retired to, ten years back. Our Norcold, in our current camper (2008) has the outside vent opening, about half the size (area) of the previous Lance 845 (2001). Why Lance reduced the side opening size is a mystery to me. The fridge, for the last couple of days has gotten behind the power curve and today, in Oklahoma, where we are headed, is forecast to be 108°F. Two degrees warmer than it was here, in Kansas yesterday. When I get home, I am going to try and add some sort of exhaust fan in the roof mounted vent. Not sure that anything is going to make mine work at these temperatures. A Coleman ice chest and dry ice may be the only answer till I get farther east and it cools down some outside.


joe b.
Stuart Florida
Formerly of Colorado and Alaska
2016 Fleetwood Flair 31 B Class A w/bunks
www.picturetrail.com/jbpacooper
Alaska-Colorado and other Trips posted
"Without challenge, adventure is impossible".


Posted By: Gale Hawkins on 07/31/11 11:31pm

nycsteve that was a good job and a good post. I can see how the top fan saved the day. If you ever have your frig out consider moving the bottom fan up under the condenser coils or at least mid way up the back of the frig.

To work well that frig is 10-12" too tall for the opening it seems. The condenser should not be viewable but be behind the alumium baffle.


Posted By: jl733 on 07/31/11 11:33pm

Those brushless DC fans draw very little power and don't produce any noticeable heat, they are very efficient. However that is actually a hard drive cooling fan and you can get the exact same one here for 7 bucks.

You will have to engineer your own clips or find some other way to mount it. You might just be better off buying from the Ebay seller though since they seem to have it figured out already.

* This post was edited 07/31/11 11:44pm by jl733 *


Posted By: tilemantim on 08/01/11 01:42am

I had one of those interior fans years ago in my Class A and it worked great. It went with it when I sold it and I wish I had it for my Camper...


Posted By: JoeChiOhki on 08/01/11 04:01am

Well done [emoticon]. I've seen those aftermarket clip on fans a number of times now, I still like my home brewed version which has been around since before they became popular [emoticon].

[image]


My Blog - The Journey of the Redneck Express
CB Channel 17 Redneck Express
'1992 Dodge W-250 "Dually" Power Wagon - Club Cab Long Bed 4x4 V8 5.9L gashog w/4.10 Geared axles
'1974 KIT Kamper 1106 - 11' Slide-in
'2006 Heartland BigHorn 3400RL



Posted By: bobndot on 08/01/11 05:16am

Great job Steve . Thank you for taking the time to share .


Posted By: nycsteve on 08/01/11 06:37am

joe b. wrote:

Thanks Steve, I am currently dealing with the same problem. Am on the return trip from Alaska to Florida, where we retired to, ten years back. Our Norcold, in our current camper (2008) has the outside vent opening, about half the size (area) of the previous Lance 845 (2001). Why Lance reduced the side opening size is a mystery to me. The fridge, for the last couple of days has gotten behind the power curve and today, in Oklahoma, where we are headed, is forecast to be 108°F. Two degrees warmer than it was here, in Kansas yesterday. When I get home, I am going to try and add some sort of exhaust fan in the roof mounted vent. Not sure that anything is going to make mine work at these temperatures. A Coleman ice chest and dry ice may be the only answer till I get farther east and it cools down some outside.


Wow! 108 is HOT. Im not anxious to try it but I think its possible for an RV fridge to hold temp in that heat. Im planning on adding one more fan on a switch at the top vent in case things start getting out of control. Possibly with minimal door opening and no additions of warm items things would work. The camper on the road seems to do a bit better, 60mph travel wind helps disapate the heat buildup. When stopped try your best to find shade.
One other thing I did which I did not mention. My research reading said that the metal wall going up behind the fridge should be no more than 1/4 inch
venting artical
from the coils. Lance built mine with up to 1 1/4 inches from the coil. I screwed in some lightweight aluminum capping material and closed the gap to 1/4" . In a phone call to NORCOLD they also said be sure this was so. The reason I guess is the narrower gap forces the cooler ventalating air closer to and faster flow over the hot fridge coils. I'll post a picture of this if anyone requests a visual.
Checkout the venting artical link above (if the link works, this is a first attempt to put a link in a post for me)it has diagrams on both venting stradegies, roof vents and side vents.
In my case I feel closing the gap to 1/4 on its own would not have solved the problem. The 2 big helps were the top exhaust fan and the interior fridge fin fan. The closing to 1/4 gap helped , how much I dont know.
Stay cool in Oklahoma, 108!!??


Posted By: btggraphix on 08/01/11 10:34am

Nice job - and tyimely for me since I have the fridge out right now. I done a major improvement to the insulation - and have gone back and forth on whether I should add some fans. I haven't really had any trouble with the fridge, but we rarely camp in great heat.

My question would be: Is it possible to hook up the fans to the circuit that turns on the fridge...in other words, have the fans automatically kick on when the fridge kicks on? I'd still want an 'override off' switch for winter camping.

In any case, nice job, both in implementation and in posting up the photos. Thanks!


2006 LanceMax 1191 - loaded and well-used
2005 C4500/Kodiak 4x4, GVWR 17,500



Posted By: btggraphix on 08/02/11 04:14pm

Hey Gale, thanks for the comments. I read your other thread - very nice job on all of it. You talked me into it and I bought a couple of qwhat I think are the same fans as you bought. They are now $20 though.....but I bought two anyway. Need to design a mount of some sort. Not sure if it makes the most sense to mount them up near the outlet grate at the top, right above the fins at the top part of the unit, or in between the upper stuff and lower stuff.

That's also a good link on the design specs for the recommended space - I'll have to measure a few things to figure out how big my gap is right now....but it might be as easy as anything to actually mount the fans on the sheet metal chimney instead of the back of the fridge....so the fans stay with the camper when you remove them.

The idea that the gap should be small to speed up air velocity make me think it would be OK for me to add insulation to the sides (covered by sheet metal) to insulate the sides a little better, as long as I don't go any narrower than the roof opening.....at least that is the way I read it.

Lastly I noticed in your (Gale) pictures that there is a tab near the top of the fridge that is bolted in. I believe on your fridge that tab is connected to the fin arrangment up there to support it. It that is the way mine started out, that tab broke off from the fins. My fins (or "radiator?") is not connected by anything other than the pipe that goes up there. I think maybe mine got broken off from bouncing through South America or something (or maybe since I bought it) but I am not sure what I can do about that. I'll look at it closer tonight to see if it did break off, but can you confirm for me that your "tab" is in fact welded or otherwise connected to the radiator?

As per usual, this project has been getting bigger and bigger daily.....at about the same rate I am getting things done so I don't seem to be getting closer to completion, but I am getting a lot done. [emoticon]


Posted By: AnEv942 on 08/02/11 05:56pm

I took some photos recently for fella on another thread concerning the side refer vents. To my surprise looking down inside the upper vent -thers a fan. I was always going to add a fan and I was leaning toward solar unit just never got around to it.

Had no idea I had a fan. After reading this post I looked again. For the heck of it I wanted to test to verify it still works. It gets power from main junction terminal in front of refer. It goes to a thermal button on top fins then to fan. Hooked up jumper wire bypassing therm button nothing happened. Thinking 10+year old muffin fan exposed to the elemnts probably quit. Then I notice a lil blue wire that disapperas from fan to ? assum to control board

So turned on the fridge-fan came on! So to work fridge has to be on & thermal button closed. Cool-I have a fan. but...

I can say in the 10+years plus the fan has never come on. As its mounted at a angle against both fridge back wall and camper back wall its quite loud inside the camper. Not unnoticeable if you werent listening loud.

I was thinking of adding a spdt switch, either manual on (bypass thermal button), off or auto on as intended. But my thought on the auto side is the thermal button must be set too high (or dead) so should get one that has lower turn on temp. I dont have temp gun, anyone know what would be a resonable replacement degree wise to have fan function on auto?


01 Ford F250 4x4 DRW Diesel, 01 Elkhorn 9U
Our camper projects page



Posted By: Gale Hawkins on 08/02/11 06:21pm

btggraphix the "tab" looking think is a "baffle" added at the factory. It is screwed to the MH wall NOT the condenser fins. It forces the air to pass through the condenser better.

Fans add a degree of reduced fire risk in my view. When on propane the chimney temps drop by about 20F in just 30 minutes after turning the fans back on with outside air temps unchanged. If the fans are running all of the time this heat build up on propane and 100F temps does not occur so the boxes stay cooler because they effectively lower the out temps behind the boxes by 20F.

Now our frig will cool just fine without fans on both gas and electric. However the duty cycle goes up and the box temps go up a few degrees especially on gas IF no external fans are running.

The fin temps will always be about the same as the chimney exit temperature but with no fans running 30 minutes earlier the hotest temp of the condenser coils read 226F degrees. The drop of 20F after 30 minutes of fan use can reduce the load on the house air-conditioner.

Our testing shows air over the lower coils does nothing to help the frig cool better. It is the air flow through the condenser cooling fins that makes a different so we decided to mount mid-way up the back side.

Mounting to the house show work just fine if the air flow is good.


Posted By: Jeep Hauler on 08/02/11 08:34pm

I have an arctic fox 1150 with the refrigerator in the slide. During hot weather the cooling fan would run constantly. The metal deflector was stapled to the side of the camper and not angled under the condenser.
[image]

There had to be a better way to cool the condenser. The metal plate and the cooling fan was removed. I went to the local home improvement store and picked up this metal fitting.
[image]
The fan was mounted in the bottom of the fitting.
[image]
[image]
A piece of wood was installed using construction adhesive. The fitting is attached to this with screws.
[image]
[image]
A short piece of round duct was attached to the bottom of the fitting to help pick up the cooler air from below.
This shows the final installation. The blue tape was the fans original location. This is 28" from the condenser, the new location is 8". The fan is now cycling during hot weather instead of running constantly.
[image]
While camping in 102 degree weather the freezer maintained 9 degrees or less during the day.


Posted By: Gale Hawkins on 08/02/11 08:49pm

Jeep Hauler that was a great job. That location is the only place air flow is critical. Should the new fan fail some year it will be very easy to replace it. Great job of making the post too.

There was no way that OEM installation was going to cut it in hot weather.


Posted By: btggraphix on 08/03/11 10:25am

Nice job Jeep hauler - that gives some more approaches to the problem.

Gale - the tab I am talking about is normally attached....it is this one here. After seeing your photos I looked and sure enough could see where the tab broke off from the tubing:

[image]

Now I need to decide what to do about it. The "radiator" does not seem to flop around or anything, and I can't easily push it towards the fridge to bring it back to contact.


Posted By: Gale Hawkins on 08/03/11 11:48am

I see said the blind.

What is weird is I just looked at our old one and the tab is miss on it like yours. I just do not remember where the tab was on the frig or not but I do remember putting a screw in the new one because I had it fixed in place before foaming the block crack.

Ours did not seem to fail due to the missing clamp so I guess it is OK as is. I would personally find a clamp for the condenser tubing and use a wire or some form of steel strap and attach it to the screw in the box.

What you do not want is to put the wire around the tube where it could rub a hole. What touches the tube must not be able to move.


Posted By: btggraphix on 08/03/11 01:24pm

Gale - my thoughts matched yours as well (a clamp of some sort but careful to not rub/crimp/cut to tubing.) So I was also trying to decide if I should use that single bolt to hold the fan mount/bracket and/or if I should use that for both purposes.

On the other hand, I kind of like Jeep Haulers method of using wood and putting them below the condenser (with or without the shroud.)

A final mounting option (at least for me) would be to attach/mount the fan bracket to the sheet metal wall... Setup that way when you removed the fridge, the fans would stay with the wall/sheet metal.

Three options to choose from. Hmmmm..... Jeep Hauler's setup could be changed to use a simple rectangle and mount 2 or 3 fans into the rectangle I suppose. I bought two fans at this point. A 3rd would bring up the Amp draw to 1 amp - I guess that still isn't much....and I think I'll probably only turn it on manually, when the temps are high. I don't know - not sure - but to have the best control, I think the idea AnEv942 is suggesting - a termostat control but also a manual override for either "off" or "on" that ignores the thermostat. Basically an "ON" "Auto" and "off". Just need to remember how the heck spdt switches need to be wired and where to go snag one (and a thermostat.)

Great thread here, thanks for all the help and apologies to the OP if this is kind of stealing his thread.


Posted By: Gale Hawkins on 08/03/11 01:39pm

Jeep Hauler has a real chimney problem because it needed to have been a foot taller and his solution is a good one in his case.

For your case I like the idea of making you a duct. Not sure my would work any better with a duct but now I would try to come up with one if I had to do it over.

The huge downside in our case since we do really have to have fans to go with something like Jeep Hauler is if the fan fails it has to be replaced because it blocks normal air flow. Again in his case that is a beautiful set up but I do not want to give up our good passive unaided air flow.


Posted By: AnEv942 on 08/03/11 06:13pm

Our fridge is simualar to Jeep Haulers-fins are at very top, dont have the depth though.

[image]

Our factory fan is also half down the wall, as mentioned I dont believe its ever come on. I ID'd the thermo disk SAS70A as a 158deg, seems high. I may change it to a lower temp 130 but otherwise keep fan in its location and function. Not sure if Ill add switch to it

Plan is to add 2 maybe 3 small fans at fins using switch to run manual/off/auto. My quandry is mounting, underneath as most have/or in front as pullers? My though is because coil/fins are in a corner with small cfm/current draw might move more air thru fins as pullers? any thoughtsEDIT: nevermind I hooked up one fan Im going to use, Obvious more air directed as pusher so underneath they go.EDIT

btggraphix -if you go the SPDT switch just insure you get SPDT/center off postion, if you want to be able to turn off. (They come both ways, without center off position) Wiring in this app. center pole would be 12v in, outer poles to fan. If adding a thermo disk you might want to install it while fringe is out, drilling fin to mount.

Oh, source for thermo disks, mouser.com page2637 found from Booster Bobs post
Edit Mouser page number changed- search 'disk thermostats'

* This post was last edited 09/10/11 12:45pm by AnEv942 *


Posted By: btggraphix on 08/04/11 04:29pm

OK - you guys have convinced me - I am going for the fans. My condenser is about 14" wide where the fins are - the fans I bought from Radio Shack are 4.75" diameter so I figure I can mount three side by side and they will be almost the exact same size as the fins.

How to mount the "thermo disks"? Do you just find the right drill bit, and drill into a fin a bit away from the tubes that run through the center?

Looking at the link (thanks a bunch AnEv for that!), it looks like either 3F11-120 or 3F11-140 depending on what temperature range you want, 120 or 140 would be the ticket......correct? You want it to CLOSE when not hitting that range, right?

It seems like the 120 would be a safer bet....140 seems like a high temperature. Even if the fridge is still efficient, you still have a really hot column of air "inside" the camper which can't be good for the cabin temp either. Thoughts? I did find SPDT (center off) switches at Radio Shack - but they didn't have any with the single LED light that tells you when it is closed. For a tiny draw, that might be a nice reminder it is on for a really low cost in amps.


Posted By: joe b. on 08/01/11 08:16pm

Today in going between Stillwater Oklahoma and Fort Smith Arkansas, the truck outside temperature gauge was showing 111°F for about an hour. Later in the week the forecast is being given for 113°F in the same area. We took most of the spoilable stuff out of the fridge, lunch meat, etc. and put it all in the freezer compartment, which is now about the same temperature as the fridge would normally be in cooler weather. The freezer is at about 40 to 45°F and the fridge part is close to 65 to 70°F. LOL I have got to do something when we get home with the fans as mentioned. Hopefully it will help during normal hot weather, not this stuff we have here, in Oklahoma and western Arkansas. Of course we are heading home to a category 1 hurricane forecast, not good karma. LOL


Posted By: nycsteve on 08/01/11 11:40am

btggraphix wrote
My question would be: Is it possible to hook up the fans to the circuit that turns on the fridge...in other words, have the fans automatically kick on when the fridge kicks on? I'd still want an 'override off' switch for winter camping.


Im sure you could but how is over my pay grade [emoticon]
I would definitly install fans if you have the oportunity. The fans use so little electric I think an on off switch would be just as good as what your asking. Constant cooling in the rear is probably better in hot weather than a fan cycling with the fridge.
Think of the fans as insurance, having had my fridge fail last year was not fun, and worth whatever effort and experimenting to stop it from happpening again.


Posted By: BoosterBob on 08/01/11 11:54am

Instead of tapping into the control circuit, I clamped a disc thermostat (Mouser Electronics #802-STC-140) to the heater chimney and wired it downstream of the fans. Power is tapped from the same 12 volts that supplies the control board then thru a rocker switch on the control panel, with a fuse to protect everything. When the chimney reaches 140, it completes the circuit for both fans and they run until the chimney cools and the 'stat opens or I cut power. It's worked very well for 3 years now. It's pleasently surprising how much difference those fans make.


Posted By: Gale Hawkins on 08/01/11 12:24pm

Sorry I quoted instead of editing to add the links so I deleted the first posting. [emoticon]

* This post was edited 08/01/11 12:32pm by Gale Hawkins *


Posted By: Gale Hawkins on 08/01/11 12:29pm

btggraphiz I would add some fans. Mid way up the back is a good location and IF you have a Side vs Roof vent I would have a fan or two blowing out the top side vent.

We dropped the power lead to each fan to floor level of the frig space so we could test running 1, 2 or 3 at the same time. Our fans cost $10 each and there is no way I would remove our frig for $30 just for the heck of it. [emoticon]

1st photo in thread is our final fan position. 1-2' higher would good too.

The fans does make a clear difference in cool down rate after a couple hours per our testing.

Cool down tests propane vs electric and fans vs no fans.

What is still being tested is IF they make any difference after the inital cool down. Currently we are seeing little to none higher temps at the same setting with 3, 1 or NO fan usage near the triple digit point. So far not even the duty cycle has increased by more than 3-4 cents a day in electric use.

On a setting of 2.5 on the slider bar marked 1-5 we see a temp range of 13/41 to 6/37 with fans and 15/42 to 7/37 over a 24 hour period but day time highs have be 4-5F lower but later this week we will have temps to check apples to apples with fan vs. no fan.

Based on a month of testing data I am convinced external fans will make a differece in 110F full sun against frig side of RV.

After I get results in 100 temps this week I plan to move the slider to 2.25 and see if I can keep the frig 34-36F average air temp inside. Right now with/with fan use 90% of the time it is 38-39F in the lower box and the freezer is 8-11F most of the time with FANS and 11-12F with no fan use.

Keep in mind the frig side only gets direct sunshine between 9-11 am each day in our test location. Also note with fan use we have seen low box temps lower than -5/20F so in normal use we are still OK with temps 20F greater than those.

I think fans will be the most help in refrigerators that can do no less than Zero/30F over night with outside temps of 75F.


Posted By: btggraphix on 08/04/11 04:52pm

PS: note the text in that article about good venting states ideally you'd put the fans right at the roof vent rather than blowing dfirectly into to fins. It would probably be easier to mount them up there......what do you guys think? Would it be better at the vent or above/below the fins? The drawback I would see is being closer to rain/moisture that might cause the fans to die a premature death.


Posted By: Gale Hawkins on 08/04/11 05:09pm

btggraphix wrote:

PS: note the text in that article about good venting states ideally you'd put the fans right at the roof vent rather than blowing dfirectly into to fins. It would probably be easier to mount them up there......what do you guys think? Would it be better at the vent or above/below the fins? The drawback I would see is being closer to rain/moisture that might cause the fans to die a premature death.


It the fans were a foot or so below the roof vent I can see that. The wild card would be if too close to the roof vent the fans could set up some currents that might not be good for getting as much air through the small gaps in the roof vent.

On thermostat value shoot some fin temps before you order. In ours even without fan use the fins are seldom as high as 120F unless on propane. 140F is the max fin temperature we have measured. Measure the temps in the U shaped turns in the condenser to just for an idea of the heat that can be there.


Posted By: btggraphix on 08/04/11 05:33pm

Gale:

1) knowing what you do about the temps you are seeing, what temp would you want the fans to automatically come on? Keep in mind that I will be able to manually override it either way (off or on?)

2) do you have a picture of the insulation you added to the return line? I'm thinking the higher quality "rubbery" split pipe insulation might work well.

Probably not a bad idea to test my fins - of course I can't run it on propane out of the box, but I guess I could hook it up to DC and AC and run it on AC. Of course now I have to go buy an infra-red temp gun. [emoticon]


Posted By: AnEv942 on 08/04/11 06:52pm

Im thinking 120 might be be good. In looking for replacement for our 158deg thermal disk on factory fan I found dealer that sold 120's as a factory disk replacement for better cooling, verifying my thought 158 too high. This both Dometic and Norcolds. So thats what Im also going to use on factory fan and add a on/off switch.

On the added aux fans I might go 100-not sure. questions are ambiant air temps, do I care if fans come on just to cool back of refer? Do I want the fans on all day if its 102? Or only to on transfer heat from fins? Then again could selct # of fans if running continoulsy. Hmmm 5 bucks could always change out up or down. If mine is like what Gale meaured 140 max, would explain why I think our fan has never come on.
Just decided 100deg-if on 2 much decrease #of fans if too little turn maually on, if not happy change thermo button.

As to mounting the disk, yes just drill couple of holes,hole spacing &dia on site-(think .93 but check) toward one end of fins out of air path but where you can reach after refer reinstalled. Mines behind tube-diificult but less air across.
You could add a pilot lamp(s).

As to adding aux fans to fins...Just finished ordering fans from neweggcoolmaster fans. Lil light but my concern is amp draw, these only push 34cfm, so 102cfm when all are on BUT they only use ~.1amp (1.2watts). So less than 1/2amp for all 3 if on. Hopefully sufficent, 5$ each worth the try, once setup easy enough to change out. With side mount vent Ill mount couple of inches under fins, should be fair coverage to move enough air dissipate fin heat and ecavuate air out/ and use little enough battery so I might leave them on.

I want the switches inside, want the fans individually controlled and option to run manually on or auto thru thermal disk and be able to turn off.

I have this seriously convoluted design for my switching but will probably do somehing simpler. Fans to be individually controled. Was going to use 4pos selector switch: off, 1 center fan, 2 outside fans, 3 all fans. Wanted to use pilots but on the ground side of fans so I know when fans are on, not when Im sending power. The 12v input to selector would be fed by SPDTcenter off. Instead of (what I think you are and i was going to do) one 12v source in to switch then select whether out directly to fans (manual) or thru thermal disk (auto), Ill feed swtich in 1 hot the other from thermal disk. Simply using selected 12v source to feed selector switch. While I was doodling required diodes for selector, realy control for pilot grounds & if I wanted pilots in sequence 1, 2 or 3 fans or show fan on posiiton center, outsides or all, thinking I could add a panle fuses for each fan...

At anyrate as fun/cool as this would be (ok sick) I'm using 3 indivual switches w pilots fed by SPDT as outlined. would be WAY simpler, have individual control over # & power to fans. I am running this inside. Now to find pilot push button switches and SPDT small enough to fit front of refer.


Posted By: Gale Hawkins on 08/04/11 08:42pm

AnEv942 from scanning over by data to night. I did pull some fin temps that are not posted but if you look on the fan vs no fan propane vs electric just look at Upper Chimney temps and that runs +/- 2F or the FIN temp of the condenser.

Look at the upper chimney exit temps. Fans help mose with LP wasted energy.

100F fin temps would be where I would start if I was going to add an automatic switch like you are talking about.

I have manual switching still for our three fans. I can run 1, 2 or 3 in any combo. I have a clip and can just clip as many wires at a time together. [emoticon]


Posted By: Gale Hawkins on 08/04/11 09:31pm

btggraphix wrote:

Gale:

1) knowing what you do about the temps you are seeing, what temp would you want the fans to automatically come on? Keep in mind that I will be able to manually override it either way (off or on?)

2) do you have a picture of the insulation you added to the return line? I'm thinking the higher quality "rubbery" split pipe insulation might work well.

Probably not a bad idea to test my fins - of course I can't run it on propane out of the box, but I guess I could hook it up to DC and AC and run it on AC. Of course now I have to go buy an infra-red temp gun. [emoticon]


1) I too see 100F a good starting point. You need to get the gun so you are not shooting in the dark on this. My data is valid for my set up but keep in mind you may have different contditions to consider. I ran ours about a month setting in the Living Room floor so I could pull data when controlling air flow over coils in different places.

That is how I learned air flow over just the lower coils did not help in cooling down the box. I could even hurt a bit in the initial cool down.

Like many others I was confused in thinking the left over coldness from the freezer coils goes directly into the lower box cooling coils but that is a false understanding. Recently by looking at a Youtube video I realized that was not the case but the fluid that cools the lower box comes from the very base of the coolin unit by way of a very small line running from the base and up into the back of the cooling unit which leads up to you second question.

2) I did did not find a picture showing that return line from the lower box cooling unit. Keep in mind as far as I know I was the first to ever insulate that line so I do not know if it is worth the effort or not. Since I installed our Amish remanufactured cooling unit I notice they do insulate that return line into the tank near the burner in the 1200 model they make new from scratch and suppy foam like I noted in my write up last year.

I used automotive AC line wrap insulation (black thick rubbery) and covered it with the 250F foil tape for fire prevention. If I was going to do it again I might just used the split pipe foam insulation like the Amish use and you mentioned.

Everyone needs to keep in mind each one needs to reason out what is best for his or she application when it comes to RV frig installation and modifications. As with others had to study as I went and I still learn from post on the subject. I actually took about a month installing our cooling unit because I was in the dark and was doing it when the kids were around for them to see and help. Basically I would stop over and over trying to get answers to my questions before proceeding. There is not a strong base of RV techs that have an understanding of the ins and outs of an RV frig I learned. The boat industry seems to have more experience because RV's are a relative new toy on the market.


Posted By: AnEv942 on 08/05/11 02:54pm

I had ordered the lil inside recirc fans when I ordered the external fans Ordered the one from newegg (7 bucks!) cause I knew would modify anyway w/ on/off swtich and paint white. We have one of the lil blue box battery fans, so I know these help, but got tired of replaceing the D batt. Went to look at nycsteve install and ended up revisiting the outside fan install pics.

Pretty convinced I need to add the deflector after looking at, for quite awhile admittedly before grasping the process, the explanation & digrame on rvmobile. http://rvmobile.com/tech/trouble/vent.htm. In trying to understand basic process my conclusion is adding the deflector would increase my almost nonexistant passive air flow arcoss the condensor fins. Also to help the fans 'pull' air from below. Mostly because on the side mount vent cover verses roof mount vent just no reason for air to go up thru fins that are tucked in corner.

In adding the fans Im seeing 2 different things.
1. simply evacuating/helping remove the hot air from behind refer, be like moving an ice chest into the shade. In doing so the ambiant air around fins would be a bit cooler-more so in a top vented refer.

2. Aiding the exchange at condensor fins, getting air thru fins. IM gathering the change from gaseous to liquid must happen at farily low temp change for this to work. On a side mounted vent this appears more critcal because the aire isnt flowing up thru fins and up vent, in my case any rising air is just going out vent. A higher volumn fan would help.

Sorry I know just rehashing what others have obviously concluded, just thinking out loud. One thing Ive always puzzled over is why some folks see temps we have never seen. Our fridge is lucky to see low 40's and its working to stay in the mid 40s.
[image]
My low volume/current fans though mounting from cieling as pullers would be way easier, fix B I think is going to accomplish the most.
Either case the deflector angle & length would be almost identicle, passivly I think fix B would also flow better.


Posted By: Gale Hawkins on 08/05/11 03:39pm

AnEv942 it seems you have a good grasp of what your situation calls for and are doing it. I agree with your thoughts on Fix B.

Having a 20 year old MH with spec on frig chimney I had no idea how poorly some are designed. One plus of the side vent is at least you can gain access to rework the chimney design fault.


Posted By: btggraphix on 08/05/11 05:10pm

FWIW, I should give Lance some credit on this one. Compared some of the others I am seeing now that I am reading up on the topic and seeing these various setups, it is pretty darned good. Last night I spent most of my time working on insulation, but I measured a number of things. The sheet metal "wall" of the chimney appears to be 5/8" from the fins and it goes straight up to the ceiling opening.

I'm going to keep moving forward on the insulation and keep thinking about what wiring scheme I want to use. I'm not sure if I want to worry about controlling each individually, but I do want the automatic based on temp and manual override as discussed above, and I do also want to have an LED that tells me if it is actually running. I don't really care if it is mounted to the fridge or to the chimney walls - and either seems to be a good options....but I'll want to be able to easily disconnect it to remove the fridge. I'm almost leaning more towards mounting on the chimney wall....that way the switches, the fans, the LED's, will all stay when you remove the fridge and fewer wires to disconnect. Only the thermo disk and it's wire would have to be disconnected to remove the fridge.

I'm not an expert by any means, but I like the looks of choice B also.

[image]

The sheet metal is bent but I'll be putting a "stop" behind it to make it flush with the edge of the opening, and also trying to seal it from rain getting past the sheet metal and towards the wall which is where all my wiring runs. You can see below some water got in there, but I think just from the vent. I'm thinking of trying to put in three more sides to that flap you see. I think that is a piece of TPO Lance used.

[image]

You can probably see why I have also thought about mounting to the actual vent at the top.....the chimney clearance is correct, it runs all the way to the roof straight up, and it would be pretty easy to mount them to the opening. Might even be able to fix/replace them from the top without pulling the fridge. BUT, I think I am too worried about rain and such getting onto the fans. So it'll either be to the fridge or a wall down there.

And AnEv, don't be sorry about thinking out loud. As far as I am concerned having others doing the same thing really helps me work through it. Thanks to NYCSteve for getting this thread going and not minding us diverting from his own system to other options.


Posted By: AnEv942 on 08/05/11 10:12pm

Thanks Gale & btggraphix, I was trying real hard to justify mounting to cieling just way easier but... fix b think they'll pull air from bottom better, less passive resistance, sure to get more air thru fins-bit out of the way from possible water (and now if it dont work I dont have to take responsibility for my own decisions Ha)-. I also see signs of water getting in ocasionally at some point. Probably on road or washing.

Your last pic btggraphix my 1st thought was 'od they didnt wrap the hole when cut out was made' but now I see they just cut 3 sides and let it hang. Rubber roof I assume. Could flap be a problem with fans?

If your vent cover comes off? I think Id set up fans so they could come out the top, Id hope they'd need replacing before fridge needs pulling again. Yours with roof opening looks way simpler, Im seeing a simple piece of z flashing bent into a box, attached to ceiling, fans just set in it or couple of screws.

Hmm now Im seeing a reason to fuse seperate power wires, if a fan actually shorts wont take out all of em. Hmm thats 2 fused power feeds to switch, 3 out to fans, now fused... gonna need a map here pretty quick...


Posted By: AnEv942 on 08/09/11 02:45pm

Umm just a passing thought. I drew up my generic wiring map. In the process I realized the power I was going to use wasnt part of refer circut and its safety cutoff themal protection. IE ours has a thermal button and fusible link- before it goes to control board. If there is a fire or other reason high temp it shuts down refer.

So IM thinking having safety cutoff on one circut and fans on another circut feeding oxegen probably doesnt quite make sense. Defeating the safety circut-just FYI

On ours getting power from refer controled 12V feed isnt an issue I think because Im using some vert low amp draw fans. even so on the road I use 12v so Ill be killing fans while in transit.

Fr those using high amp fans where pulling from refer board might be an issue, might use it to activate a relay to feed unregualted power for fans... just a thought
Mark


Posted By: btggraphix on 08/09/11 03:35pm

Hey Mark - since I'll be out of commission on this project for at least a week (I'm having to button things up quickly to use the camper for a funeral trip) I'll let you get the wiring all figured out and then copy you. Thanks for the help you have provided so far. Silversand has also given me a few ideas on how to line the chimney walls for fire protection - I'll have a little time to investigate before I dive back in on this project.

BTW: Nice camper projects page in your sig - I hadn't even started looking for an LED swivel light for the headboard and there's one you've already found and installed!


Posted By: Super_Dave on 06/07/12 08:51am

For whatever reason, my camper only has 1 - lower side vent where a lot of campers I'm seeing on this thread had an upper side vent, making better fan placement a lot easier. That being said, I've gone with what my camper has given me without taking the frig completely out. I have a thermostat on order but it will come too late for my trip next week so I've gone manual swith for the time being.

120mm X 120mm case cooling fan from Fry's Electronics, $14.00 and $6 worth of hardware and a switch. Now I guess we'll see if there is any difference. Even a couple of degrees can mean the difference between a cold or warm drink.

Before:
[image]

After:
[image]

[image]

[image]


Truck: 2006 Dodge 3500 Dually
Rig: 2018 Big Country 3155 RLK
Boat: 21' North River Seahawk



Posted By: wnjj on 06/07/12 09:43am

Super_Dave wrote:

For whatever reason, my camper only has 1 - lower side vent where a lot of campers I'm seeing on this thread had an upper side vent, making better fan placement a lot easier.


Because yours has a roof vent, which flows warm air more naturally than a side one.


Posted By: Super_Dave on 06/07/12 09:57am

I think it should have had a side access if for nothing more than service ability. The top vent it hermetically sealed and doesn't even allow for one to clean the coils.


Posted By: Raften on 06/07/12 01:14pm

Last summer I installed a fan at the top and one at the bottom and used in in 100 degrees plus weather. It helped but not as much as I had hoped for. Pretty sure part of my problem was the fact that the direction I parked in exposed the reefer vent to full sun all day. That couldn't be helped at the time. I rigged a shade that helped. This year, if I ever do get a chance to get out I will have a improved fan system. Great ideas here, keep the coming.

Forgot, I also had a fan inside the reefer but I plan to up the size of that also. Keeping the door closed as much as you can is very important, going to a ice filled cooler for drinks.


Posted By: nycsteve on 06/07/12 04:40pm

wnjj wrote:

Super_Dave wrote:

For whatever reason, my camper only has 1 - lower side vent where a lot of campers I'm seeing on this thread had an upper side vent, making better fan placement a lot easier.


Because yours has a roof vent, which flows warm air more naturally than a side one.


They make a fan that mounts at the roof vent to pull the air up and out. Some are solar powered.


Posted By: Super_Dave on 06/07/12 06:01pm

nycsteve, have you seen what would be required to do the install? A real PITA on a good day and everything went right.


Posted By: kerry4951 on 06/07/12 06:57pm

Super_Dave wrote:

For whatever reason, my camper only has 1 - lower side vent where a lot of campers I'm seeing on this thread had an upper side vent, making better fan placement a lot easier. That being said, I've gone with what my camper has given me without taking the frig completely out. I have a thermostat on order but it will come too late for my trip next week so I've gone manual swith for the time being.

120mm X 120mm case cooling fan from Fry's Electronics, $14.00 and $6 worth of hardware and a switch. Now I guess we'll see if there is any difference. Even a couple of degrees can mean the difference between a cold or warm drink.

Before:
[image]

After:
[image]

[image]

[image]


Super Dave
I like your idea. Please post another pic after you get the thermostat installed. Where did you get the thermostat?? What temp thermostat are you going with??
Is the 12 volt power supply wire going to the fan always "hot" when the frig is just turned on?? Thanks


2009 Silverado 3500 dually D/A, Supersprings, Stable Loads, Bilsteins, Hellwig Sway Bar.
2010 Arctic Fox 1140 DB, 220 watts solar, custom 4 in 1 "U" shaped dinette/couch, baseboard and Cat 3 heat, 2nd dinette TV, cabover headboard storage, 67 TC mods


Posted By: Super_Dave on 06/07/12 08:44pm

The 12v power is always hot when the switch on the batteries is on. If you see the 2 spade connectors under the yellow sticker, that is where I tied in my fan power. The sticker said, "12V input" on one tab and "ground" on the other tab so I jumped on that.

For my thermostat, I'm going to use a cool only non programmable home thermostat. They range from 50 degrees to 90 degrees. I planned on setting it at 75 - 80 degrees to kick on. I am ordering the thermostat from Graingers.


Posted By: kerry4951 on 06/07/12 08:54pm

Super_Dave wrote:

The 12v power is always hot when the switch on the batteries is on. If you see the 2 spade connectors under the yellow sticker, that is where I tied in my fan power. The sticker said, "12V input" on one tab and "ground" on the other tab so I jumped on that.

For my thermostat, I'm going to use a cool only non programmable home thermostat. They range from 50 degrees to 90 degrees. I planned on setting it at 75 - 80 degrees to kick on. I am ordering the thermostat from Graingers.

Thanks for the info. Great pics!!


Posted By: AnEv942 on 06/08/12 09:22am

Ya the upper side vent is nice for access but creates it own issues-I think the need for fans even more needed as theres limited air movement thru the condenser fins. Ours the refer is in slide out, so the upper side vent is mandatory, Ive seen side vents on non slide but funtionaly the roof vent is better. For access issues though you Could add upper side vent I suppose. I had thought the roof vents had a removable cap?.

Hmm i thought I had posted ours after finishing but I guess not. I used 3 smaller fans directy under condensor.
[image]

Wired them to run thru thermo disk or manually, each with its own on/off switch so i can run 1, 2 or all 3. Still havnt got the thermo button yet so have been using manually.
I also think the added baffle helps when fans arent running to passivly create air flow thru the condensor fins.

[image]

I cant say the fridge runs any cooler or gets colder but it does run less if that makes sense..And it doesnt get as warm as the day passes whereas before the temp would usually climb on hot days and be running continously. So the fans do evacuate the ambiant heat that saturates the box-but does seem to help run more effciantly or consistantly.

I had also installed the interior fans. Im still not sure about them. Fridge will cool down faster from dead start. However if left on continously when on gas seems to start to warm. I had individually switched and now only run 1. Most effective is cycling on & off but isnt practicle. I had install the interior fans after having used one of the lil battery ones. It did work-but it sat on shelf verses being directly on transfer fins. Might be me but seems fans after a point have reverse affect-possibly too much air? I had powered from light power source, wonder if I can sneak another wire and power from refer so inside fan only comes on when running...


Posted By: kerry4951 on 06/08/12 09:36am

I am on my third RV, and they all had the roof top frig vent. I have never noticed any issues with lack of cooling. In fact I have to keep checking that my frig isnt cooling too well, even when its hot out. There are times when I turn back the dial. I am wondering if there is that much difference from a roof top vented frig versus the side top vented kind? It seems that more owners with the side vents are having the cooling issues. I am just curious if the two different set ups perform that much differently. Im sure some of our members had experience with both.


Posted By: Gale Hawkins on 06/08/12 11:38am

kerry4951 wrote:

I am on my third RV, and they all had the roof top frig vent. I have never noticed any issues with lack of cooling. In fact I have to keep checking that my frig isnt cooling too well, even when its hot out. There are times when I turn back the dial. I am wondering if there is that much difference from a roof top vented frig versus the side top vented kind? It seems that more owners with the side vents are having the cooling issues. I am just curious if the two different set ups perform that much differently. Im sure some of our members had experience with both.


Two door refrigerators that are roof vented correctly seem to work fine for a long time without fans.


Posted By: devildog1971 on 06/08/12 04:58pm

Refrigerator mods you did helped me, my refer is also in my slide out, again thanks


2019 Northern Lite 10-2 EXCDSE Dry Bath 2007 G M C dually crew cab and 2018 Harley Davidson Limited Low


Print  |  Close