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Topic: Norcold Refrigerator Vent Fan Install with Switch (pics)

Posted By: ElPasoTom on 06/18/11 08:26pm

Also see inside fan mod if you're interested.

Inside Fan Mod Clicky

With temps in El Paso over 102 again today I realize my refrigerator is struggling to maintain temperature. Mid-day temps showing 42-43 inside the fridge. I prefer 36-38 so I thought I'd put a little fan behind the fridge to help move things along.

I've seen fans designed for this purpose but I wanted a less expensive solution, and besides the space back there is tight and I didn't want to move anything.

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Parts for this job

Trying to find the ideal place was difficult but I chose a location that was easy, allowed for simple install and was easy to service later.

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[image]

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I wanted to be able to switch the fan off when the temps were lower so I needed a place for the switch. I mounted a piece of scrap wood and screwed in the switch mount.

Now for all the wiring. I searched the internet for hours looking for best way to wire this as I am not electrically gifted..... at all. I saw the package the switch came in and it looked pretty basic so I gave it a try.

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Hooked up the hot (with a 1/2 amp fuse from Radio Shack). Load connector went to the fan red wire. The fan blue wire went to the switch ground and to the ground in the rear panel. Held my breath and clicked the switch... it works!

Now to mount the switch and make the connections permanent.

[image]
[image]

I will have more data tomorrow but the fridge began cooling down quickly and I've set it for "3" instead of "4" so we'll see if the temps hold 38 deg on a lower power setting since tomorrow will be over 100 again.

Hope this mod helps someone else tackle some wiring. Nothing fancy but it moves air and that's all I wanted.


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Posted By: CISCO8325 on 06/18/11 08:30pm

like it


Posted By: GENECOP on 06/18/11 10:27pm

Thanks, it helps, I will be going for it any day now....


Posted By: old guy on 06/18/11 11:29pm

I did that to mine only yours looks far better than my install. esp the switch holder


Posted By: Gale Hawkins on 06/18/11 11:42pm

That is a nice job.

After I installed ours I read where you need to extend a duct like shield above/below the fan a few inches so exiting air flow does not in part get sucked back in on the intake side. In your case you could test it really easy.


Posted By: ElPasoTom on 06/19/11 08:13am

Link to Switch

The switch I used.

Link to fuse holder

The fuse holder.

I also bought a package of (4) 1/2 amp fuses.


Posted By: ElPasoTom on 06/19/11 08:16am

Gale Hawkins wrote:

That is a nice job.

After I installed ours I read where you need to extend a duct like shield above/below the fan a few inches so exiting air flow does not in part get sucked back in on the intake side. In your case you could test it really easy.


I saw this with other fans, but I don't really have the space. Even with the inefficiency hot air rises, and all I hope to do is give it a little push.

Depending on how this performs I may also later add the solar powered fan for the top of the vent area. I don't plan on camping in the really hot areas if I can help it. I'm out of here Tuesday for the Grand Tetons and Yellowstone where I probably won't need the fan at all. [emoticon]


Posted By: ElPasoTom on 06/19/11 08:21am

TEMP Update!

This morning the refrigerator was 37.2 degrees on setting 3 out of 5. It's 75 degrees at 6AM going to 105 deg this afternoon. I do not think the fridge can keep up with these extreme temps so I may have to go to 4 or 5 to keep temps down, however using 3 instead of my usual 4 is an improvement.

I also have to realize a gas absorption refrigerator can only do so much.


Posted By: Ron3rd on 06/19/11 09:31am

Nice job ElPasoTom,
Just a quick question; what's the idea behind this mod? Is it to push the air "up" through the roof vent, and thereby increase efficiency?


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Posted By: ElPasoTom on 06/19/11 09:40am

Ron3rd wrote:

Nice job ElPasoTom,
Just a quick question; what's the idea behind this mod? Is it to push the air "up" through the roof vent, and thereby increase efficiency?


These refrigerators remove heat by absorbing it through fins inside the refrigerator, then release it behind the refrigerator in the space between the fridge and the wall of the trailer.

Convection should bring in cooler air from below and "chimney" the warmer air out of the roof vent. As the temperature rises from ambient air, then the difference between the incoming air and air inside the vent space shrinks and you lose the "convective" movement.

A fan is supposed to help move that warmer air up and out of the vent helping retore some efficiency to the fridge in warmer temps.

At least this is how I understand it.


Posted By: Dieselgem on 06/19/11 09:42am

This is a great modification. I was wondering why you did not mount the switch inside the coach?


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Posted By: ElPasoTom on 06/19/11 02:08pm

Dieselgem wrote:

This is a great modification. I was wondering why you did not mount the switch inside the coach?


It was much quicker and less hassle to just mount it close to the fan. You could do that if you wanted to route the wire inside.


Posted By: ElPasoTom on 06/19/11 02:10pm

TEMP Update

Mid-day temps at 2PM this afternoon.

[image]
Can't really complain about it.

Indoor temps are inside trailer, Outside represents the sensor in the fridge. It's parked next to our house.


Posted By: pbitschura on 06/19/11 02:14pm

ElPasoTom wrote:

Dieselgem wrote:

This is a great modification. I was wondering why you did not mount the switch inside the coach?


It was much quicker and less hassle to just mount it close to the fan. You could do that if you wanted to route the wire inside.
I did this mod and installed a lighted rocker switch directly above the frig. I only use it when outside air temp is above 85. The wire to the switch comes through the paneling and is less than two feet remote from the fan.


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Posted By: NickT on 06/19/11 10:55pm

Good job Tom!
Because of medical reasons,I need 120vac when we camp.
I used a 12v ac/dc fan on a wall wort plugged into the fridge plug.When there is power there is air movement,no switch.


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Posted By: Gale Hawkins on 06/19/11 02:20pm

That is like use too. I find the box temps will rise until about 8 pm because one I used noted max hi/low reading recorded since last reset.

I kind of like the switch located outside too. If the frig is in use the fan is running unless it is winter time and I can hear the fan when walking beside the lower frig vent so I just open it and turn it off if not in use.


Posted By: dougwhite on 06/19/11 05:53pm

"Cool" mod.......pardon the pun. I did the same with a computer case fan, except I mounted mine in the opening just below the vent hole for the fridge in the roof.


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Posted By: LarryJM on 06/20/11 03:13am

ElPasoTom wrote:

Ron3rd wrote:

Nice job ElPasoTom,
Just a quick question; what's the idea behind this mod? Is it to push the air "up" through the roof vent, and thereby increase efficiency?


These refrigerators remove heat by absorbing it through fins inside the refrigerator, then release it behind the refrigerator in the space between the fridge and the wall of the trailer.

Convection should bring in cooler air from below and "chimney" the warmer air out of the roof vent. As the temperature rises from ambient air, then the difference between the incoming air and air inside the vent space shrinks and you lose the "convective" movement.

One thing I have found on the two trailers I have had a 1981 Fleetwood Prowler and our current 2007 HR Aluma-Lite is that the manufacturers do a poor job in sealing the chimney especially at the top of the frig. There should be a panel at the very top of the frig even with the back of the frig that seals that open space. The only way to adequately check this is to remove the refer vent cover on the roof. If that top baffle is not installed and sealed properly you can form a "HOT POCKET" of non moving air that can seriously interfer with the already delicate natural "chimney" effect which is critical for the refer to work correctly. If you have this issue all the fans, etc. will only marginally help. Same goes for sealing the sides, but issues in those areas effect the "chimney" function less than that one at the top of the frig.

Finally, any leaks around the frig along the back will draw cooler air from inside the trailer and cool the air in the chimney and doing that higher up near the roof only slows down the natural temp delta circulation flow when the cooler air mixes with the hot air in the chimney column.


A fan is supposed to help move that warmer air up and out of the vent helping retore some efficiency to the fridge in warmer temps.

At least this is how I understand it.


Larry


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Posted By: Exocet on 06/21/11 07:03pm

After looking at mine, it seems like a fan at the top would be better given the large cooling fins near the top. But, that would be much harder to install.


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Posted By: w6pea on 06/21/11 08:34pm

Looks good.


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Posted By: Gale Hawkins on 06/21/11 08:35pm

Exocet wrote:

After looking at mine, it seems like a fan at the top would be better given the large cooling fins near the top. But, that would be much harder to install.


I thought that at first but it does not seem to be the case.

You are correct the critical part that needs air flow is the large cooling fins near the top we learned in lab testing our frig in the living room.

The lower coils are cooled in part by the very cold coolant coming out of the bottom of the foam block. Naturally the draft will cool them first too.

Fans mounted below the large cooling fans near the top turned out to be the best location for our Norcold 6162 unit so we mounted ours mid way up the back.

In testing by only blowing air across the lower coils and NOT the top fins did not enhance the cooling power of the frig in any way that we could measure.

Fans at the top are OK and for some may the easier to install but it is the volume of air moving across that heat exchanger at the top that is "required" for an RV frig to work were we found the most bang for the buck. There is ducted cooling kit that someone selling on the internet to help but I did not like that option because WHEN the fan fails there is little passive airflow able to pass up the back and over that heat exchanger fins.


Posted By: ElPasoTom on 06/21/11 09:28pm

Gale Hawkins wrote:

Exocet wrote:

After looking at mine, it seems like a fan at the top would be better given the large cooling fins near the top. But, that would be much harder to install.


I thought that at first but it does not seem to be the case.

You are correct the critical part that needs air flow is the large cooling fins near the top we learned in lab testing our frig in the living room.

The lower coils are cooled in part by the very cold coolant coming out of the bottom of the foam block. Naturally the draft will cool them first too.

Fans mounted below the large cooling fans near the top turned out to be the best location for our Norcold 6162 unit so we mounted ours mid way up the back.

I too was prepared to install a fan at the top of the vent area, however, I have noticed such a dramatic increase in performance that I don't think it will be necessary. It has been between 100-106 in El Paso, TX the past week and since the install I have seen temps from 34.3-37.2 on settings 3 and 4. If it can do this in these temps I'm sure the efficiency will be amazing when camping in the 70's and 80's in the mountains and at elevation.

I understand what you are saying about concentrating airflow by the fins, but IMO any increase in convective air movement will produce an increase in performance... how much... who knows just get that air flowing!!![emoticon]

In testing by only blowing air across the lower coils and NOT the top fins did not enhance the cooling power of the frig in any way that we could measure.

Fans at the top are OK and for some may the easier to install but it is the volume of air moving across that heat exchanger at the top that is "required" for an RV frig to work were we found the most bang for the buck. There is ducted cooling kit that someone selling on the internet to help but I did not like that option because WHEN the fan fails there is little passive airflow able to pass up the back and over that heat exchanger fins.



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