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 > Older fridge cooling Better on 110 than propane

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dougrainer

Carrolton, Texas

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Posted: 07/08/19 11:51am Link  |  Quote  |  Print  |  Notify Moderator

ernie1 wrote:

dougrainer: Neither of my friends nor I have slides in our rvs and since we have identical problems common to two different models of new Dometic fridge in that the fridges work fine on ac but poorly on propane I'm certain that the issue is propane related and less an improper installation. Question is, what to look for that the rv repair shops in conjunction with Dometic techs can't resolve. I think Dometic has flaked on this issue. My thinking is either an undersized gas jet, a crimp or restriction somewhere in the gas supply system (which might be a Dometic design issue). Gonna check the gas supply pressure and, if less than 11.5, adjust the regulator accordingly. Can't get any info on the proper jet size nor availability because Dometic says they can't give that info out nor can they give any references probably due to a liability issue. So Doug, what do you think?


What do YOU think the odds are that all your friends would have a Jet issue on the 8555 that were probably built months or years apart at Dometic? ALL in your circle of friends. Nobody else including me that has worked on thousands of RV refers over the years has experienced such a problem. MOST operational problems ARE caused by the OEM install. The refer is just an appliance and relies on correct 120 voltage and LP pressure. Nothing else that would be Dometic's fault. You want to blame Dometic. Understandable. BUT, My experience shows that Appliance makers are usually 100 percent correct that there is nothing wrong with the appliance, and is the supply items and the OEM's that are causing the problems. THAT is why it appears that Dometic seems to "flake" off. They KNOW there is nothing wrong with the Refer and cannot force incompetent Service people to step up. Doug

NRALIFR

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Posted: 07/08/19 12:10pm Link  |  Quote  |  Print  |  Notify Moderator

Ernie, where’s the refer’s top vent on your RV? Roof or sidewall?

If it’s in the sidewall, that’s essentially the same as a refer installed in a slideout.

Either way though, you should get the installers guide for your fridge, and compare the clearances, insulation, and air baffles with your install.

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JRscooby

Indepmo

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Posted: 07/08/19 12:33pm Link  |  Quote  |  Print  |  Notify Moderator

dougrainer wrote:

JRscooby wrote:

dougrainer wrote:


Also, Are any of you or your friends refer installed in a slide room? THAT is also a different situation that usually calls for a separate exhaust fan blowing out the top door. Doug


I can not disagree with this, but just for my understanding, could you tell me why this is true?


Simple. The normal install for a RV refer is to have the cold air come in thru the bottom outside door and convection the air thru the condenser and up and out the roof vent. Normal convection air gets this done. Larger RV refers need an addition fan to help blow the air up and out, which the refer maker installs if needed. Now, when you have the refer in a slide out, the air flow IS going up, but must make a 90 degree turn and out the upper vent door since you do not have a roof vent in a slide room. Most OEM's do a poor job of making the upper wood cabinet with the required wood baffles to help turn that air and out the upper door. So, a lot of the hot air stays caught behind the upper refer and allows poor ventilation and cooling. Sooo, what I do is modify the upper back of the cabinet to seal off any place that can trap air. I then add just 1 12 volt refer fan just inside that upper door blowing out to force the hot air out the upper door. Also, when you remove that upper door and you can see most ofthe condenser fins, that is also a problem. That is why it is critical to make sure you have a wood baffle as close to the back side of those fins to make sure the cooling air goes thru the condenser instead bypassing between the sidewall and the condenser. THIS is the most common OEM error on baffling the refer cabinet. Doug


Thank you. Have the same issue with popup. But with the baffles I put in I only need to run the fan when the outside temp is over 100...

ernie1

Sacramento,California,USA

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Posted: 07/08/19 09:30pm Link  |  Quote  |  Print  |  Notify Moderator

I want to state this again and for the last time. The refer works fine and as it should on ac and as expected on 12v. BUT not very well on propane at all. So my thought is that the installation is proper otherwise it would not cool properly on ac. It is just the propane setting that won't cool properly. Again, my 2 friends have an identical refer and one also has a Dometic but a smaller model and we have the identical problem. So something is wrong that is common to these Dometics. Also I might as well say it loud and clear now, Dometic as a manufacturer is not worth a darn and has failed to correct this problem. Dougrainer, with your 40+ years of experience I feel you can do better than tell me that the chances of the wrong sized jets being installed on all three of these refrigerators aren't logical and that Dometic is blameless. What I expected from you was what the problem with these refers are. If the refers work fine on ac and 12v but not well on propane why is it a faulty installation? These are brand new units and Dometic via repair shops has been diddling with them to a point where they gave up and told the owners that the refers were operating as expected. Come on Doug you can do better.

ernie1

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Posted: 07/08/19 09:49pm Link  |  Quote  |  Print  |  Notify Moderator

NRALIFR My refer has two side vents and I've installed two 12v fans behind the top vent and when the fans are running I've actually noticed the refer losing ground and the inside warm up a degree or two so now I've quit running the fans totally. You're right about reading the installation manual and I will but I'm still saying if the installation was not proper, why does the unit run fine on ac and 12v BUT not propane. Also, My two friends with Dometics of the same vintage complain about the same issue. Logic is clear to me in this case that there is something not right with the propane part of these refers. I'm tired of hearing about how blameless Dometic is and when I reach out for help to their tech people they are clueless, rude and condescending. At this point I think I'm beating a dead horse in trying to find a solution and getting wound up in company loyalty issues etc rather than dealing with facts.

NRALIFR

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Posted: 07/08/19 11:08pm Link  |  Quote  |  Print  |  Notify Moderator

ernie1 wrote:

NRALIFR My refer has two side vents and I've installed two 12v fans behind the top vent and when the fans are running I've actually noticed the refer losing ground and the inside warm up a degree or two so now I've quit running the fans totally. You're right about reading the installation manual and I will but I'm still saying if the installation was not proper, why does the unit run fine on ac and 12v BUT not propane. Also, My two friends with Dometics of the same vintage complain about the same issue. Logic is clear to me in this case that there is something not right with the propane part of these refers. I'm tired of hearing about how blameless Dometic is and when I reach out for help to their tech people they are clueless, rude and condescending. At this point I think I'm beating a dead horse in trying to find a solution and getting wound up in company loyalty issues etc rather than dealing with facts.


Your logic is correct. I know you’ve mentioned that it works fine on AC more than once but I forgot that when I made my last post. I would check the LP pressure before doing anything else.

All I can say regarding fans is that on my current unit, I have one fan in back, and it’s mounted about halfway up in an area where there’s a lot of room between the tubing. It’s pointing up, blowing through the condenser fins at the top, and the roof vent above it. It’s actually a fairly slow speed, quiet fan. You can hardly hear it. I don’t think high speed fans are necessary back there.

One thing that is different about running in LP mode versus AC mode, is the waste heat from the flame coming out of the chimney. There are more btu’s of heat to exhaust out the top vent when the fridge is running in LP mode than when it’s in AC mode. The baffle at the very top of the fridge should direct all of the heat coming off the cooling unit tubes and fins AND coming out of the chimney to the top vent, and not let any of it enter the dead air space that’s typically left on top of the fridge. If there’s even a small gap at the sides of the top baffle, heat will enter the area behind it. I’ve found that it’s best to fill that area with insulation to prevent that.

The heat produced by the flame doesn’t all go into the boiler perk tube of the cooling unit like it does when running in AC mode. The chimney should have a twisted strip of metal hanging down close to the bottom called a baffle. It’s supposed to concentrate the heat in the proper area so the solution inside the perk tube will boil. If that baffle isn’t there, the heat just flows up the chimney and the boiler doesn’t get hot enough. Even with the baffle though, there’s a lot of heat flowing out of the chimney. Enough to burn you when the flame is on. So, make sure the baffle is there, and that the end closest to the flame isn’t burnt off. Make sure there’s nothing obstructing the flow of heat coming out the chimney. Also make sure the chimney is clean of rust. A 10 gauge shotgun wire brush can be used to clean it. Of course you have to pull the baffle out for that.

Here’s an image of a cooling unit I like to refer to. You can see a representation of the baffle in the lower right. It looks like a figure eight.

[image]

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red31

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Posted: 07/09/19 07:58am Link  |  Quote  |  Print  |  Notify Moderator

ernie1 my thinking goes like this!, usually the propane BTU on high is more than the 120v watts. if natual convection is enough for 120v it may not be for propane and causing areas that do not need heat getting heat!

What is your pressure? How far away from the wall is the condenser (baffeled?)

dougrainer

Carrolton, Texas

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Posted: 07/09/19 08:46am Link  |  Quote  |  Print  |  Notify Moderator

ernie1 wrote:

I want to state this again and for the last time. The refer works fine and as it should on ac and as expected on 12v. BUT not very well on propane at all. So my thought is that the installation is proper otherwise it would not cool properly on ac. It is just the propane setting that won't cool properly. Again, my 2 friends have an identical refer and one also has a Dometic but a smaller model and we have the identical problem. So something is wrong that is common to these Dometics. Also I might as well say it loud and clear now, Dometic as a manufacturer is not worth a darn and has failed to correct this problem. Dougrainer, with your 40+ years of experience I feel you can do better than tell me that the chances of the wrong sized jets being installed on all three of these refrigerators aren't logical and that Dometic is blameless. What I expected from you was what the problem with these refers are. If the refers work fine on ac and 12v but not well on propane why is it a faulty installation? These are brand new units and Dometic via repair shops has been diddling with them to a point where they gave up and told the owners that the refers were operating as expected. Come on Doug you can do better.


I can do better? Remember, you are getting what you are paying for. There are 2 things that would make LP not operate as well as 120 volt. I am not getting into jet orifice sizes. LP pressure---after all these posts, have you VERIFIED the actual LP pressure AT the refer? The other is the condition of and IF installed the LP flame baffle. If it is missing and has been burnt/corroded, it will not disburse the flame correctly to heat the flue correctly to the right BTU. Sorry, I have a life other than these forums, and I do not go back and read ALL the previous responses. I missed the fact that the refer operated on 120 correctly but not LP. No I did NOT, I TOLD you to verify the LP pressure before doing anything else. NOW, I go back and found you hijacked the original thread. CHECK THE LP PRESSURE WITH A MANOMETER. THEN POST THE RESULTS;. I AM THRU WITH YOU. Doug

maillemaker

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Posted: 07/09/19 09:02am Link  |  Quote  |  Print  |  Notify Moderator

If your refer is working fine on 110 then there is nothing wrong with the cooling system. Something is wrong with the LP burner system.

Most likely, something is gunked/rusted up.

Possibly, there's something wrong with the gas supply.

Steve


1990 Winnebago Warrior. "She may not look like much but she's got it where it counts!"



ernie1

Sacramento,California,USA

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Posted: 07/09/19 04:30pm Link  |  Quote  |  Print  |  Notify Moderator

Everyone and Doug, thanks for your help and I will at this point check the lp pressure from the regulator to the refer at the gas valve and dismantle the chimney looking for any irregularities along with a thorough cleaning of this area.

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