Fridge cools on A/C but not on Propane - EDIT: FIXED!

[cpachristopher]

Hi All, I've been several years with out a TT, but wife convinced me it was time to jump back in, and so far so good, except for the fridge.

I'm pretty handy, but I called for help on this one. The repair guy came out and was baffled.

It is a Dometic, very small, no adjustment knobs anywhere. Trailer is a 2015 model so I assume the fridge is, too.

Here's the situation:

Load fridge @ Home while plugged in to shore power. It worked reasonably well. We went camping and switched to propane. Within 24 hours it was clear that the fridge was not cooling. Fortunately we had a cooler, so it worked out.

Fast forward to the next week. I had the TT parked at home on shore power. I put a case of bottled water in it, and it brought the temp down nicely. I unplugged power and switched to gas and within 2 days, the bottles barely below ambient temp..

Service guy came out - we checked and saw flame. The cooling fins are warm. The check light is NOT on.

He poked around and scraped some soot off and said that I should try again and make sure I had flame,

So....Pre-camping last week I loaded the fridge with bottles of water again. The odd thing is that the freezer (tiny, but internal to the fridge with a fold-down door) was really cold - icing up on the floor of the fridge. However, the fridge itself was not cold. I took the door off of the freezer and left the bottles inside, and sure enough, they got nice and cold - all on A/C

So, what the heck am I missing here. It seems I have flame. The A/C power is clearly heating the ammonia enough to chill the thing. And I have a freezer but not a fridge, but only on A/C. I rarely have A/C when camping,

I'd really love to avoid buying a new fridge but that is 1/3 of the reason my wife wanted another trailer (1/3 being bed off ground, 1/3 being shower)

I'm not home else I'd get the model of fridge.

Trailer is a 2015 Coachmen 16FB

If anyone has any ideas, I'd love to hear them.

[SidecarFlip]

midnightsadie wrote:
the taking apart and cleaning should be less than an hour U tube how to clean a rv refrig. its not hard. they were made to be removed and cleaned. DO NOT MAKE THE ORFICE HOLE ANY BIGGER.

Lets elaborate on that a bit.... soak the orfice in isopropyl (think thats ciorrec) alcohol and don't even think about sticking anything in the hole. Blow it out with air only. Some have a small piece of sponge inside that acts as a filter that will need cleaning too.

Have fun, be careful with the parts and take your time.

[midnightsadie]

the taking apart and cleaning should be less than an hour U tube how to clean a rv refrig. its not hard. they were made to be removed and cleaned. DO NOT MAKE THE ORFICE HOLE ANY BIGGER.

[cpachristopher]

He is not coming back for sure. I hadnt considered pressure. Ive got a spare regulator I'll have to try. Stove and water heater are acceptable for what it is worth,

So a good cleaning of the burner/flue/etc and check regulator. Sounds like a fun Saturday

dougrainer wrote:
If it works on 120 and not good on LP and the flame ".looks" OK. THE FIRST THING ANY COMPETANT TECH DOES IS VERIFY THE LP GAS PRESSURE. NOT doing that shows lack of knowledge and skill and I would not hire/use this part changer anymore. A 1 inch drop in LP pressure will have a drastic affect on the cooling capability and you will not be able to tell by the flame size/look. Doug

[pnichols]

I've noticed on our propane refrig that when running normally on propane, it's burner flame makes an audible roaring sound that can easily be heard outside when standing close to the outside ventilation grill, and can even be heard inside if I put my ear up to the cabinet wall where the refrigerator is mounted.

Last week my refrig quit cooling on propane, too (but cooling on 120 volt AC) - however there was still a flame in the burner when it was running on propane -> just too small of a flame, such that I could hardly hear it outside when standing close to the outside ventilation grill.

With the tip of a flat bladed screw driver I merely scraped the grey/black crud off around the slits in the tube where the propane comes out to burn and ... wa-la ... the flame became larger and it roared again. Our refrig now works fine on both 120 volt AC and propane!

[dougrainer]

If it works on 120 and not good on LP and the flame "looks" OK. THE FIRST THING ANY COMPETANT TECH DOES IS VERIFY THE LP GAS PRESSURE. NOT doing that shows lack of knowledge and skill and I would not hire/use this part changer anymore. A 1 inch drop in LP pressure will have a drastic affect on the cooling capability and you will not be able to tell by the flame size/look. Doug

[cpachristopher]

Wow - thank you all for the ideas.

It sounds like I have a little work to do this weekend!

Getting the burner out looks like a serious pain. Is it easier to pull the whole fridge out from inside the TT and clean it that way?



ETA - Running fully level.


ETA II - I've got to change my sig line!

[SidecarFlip]

midnightsadie wrote:
also it takes a good 12hrs or more to cool down these rv frig units. then load with cool or frozen goodies. my money is the burner needs a good cleaning. there not hard to do, just not much room to get it out of the hole.

Tell me about it. I have to physically remove the screws holding the upper louvered vent and then take a putty knife and pop it off the butyl tape before I can access my flue baffle and then clean the tape off and replace it and screw down the louvered vent again. A real PITA.

Not something that needs regular cleaning but it does need to be addressed every few years (depending on how much you run on propane).... I usually run 110 shore powered and propane when camping with no hookups. The 110 heating element isn't as efficient as the propane either. There is around a 50 degree temperature difference between the 110 heater and the propane, with propane being hotter and the hotter the boiler runs, the better the cooling is.

[jplante4]

Bird nest in the stack.

[midnightsadie]

also it takes a good 12hrs or more to cool down these rv frig units. then load with cool or frozen goodies. my money is the burner needs a good cleaning. there not hard to do, just not much room to get it out of the hole.

[SidecarFlip]

The boiler has a removable baffle (the wire handle is at the top), remove it and clean off the soot. If it's missing, that is your issue, the baffle has to be there to contain the heat from the flame.

Also, check the upper outside condenser (above the sloped tubes), is it warm, should be. The freezer cools first, then the fridge, always. You might need some auxillary fans to pull the air through the heat exchanger unit as well.

Finally, are you running the fridge level (within a half bubble on a mechanics level)? Ammonia fridges have to run in a fairly level position to work properly.

[justaboutretire]

I agree, check the burner. May not be a hot or big enough flame. Check the stack for obstructions. There should also be a thermocouple in the stack not sending the correct values to the refrig thermostat.
Does the control panel have indicating lights? Some models will blink a code of the problem while on gas or electric.
Bill

[midnightsadie]

fire your service guy. he should have taken the burner out cleaned it. and the stack ,even though you have flame does not make it enough it should have been cleaned.those little holes get clogged easy.