Dometic cooling capacity has decreased

[WesternHorizon]

1995 Class C with a RM2611

I bought it 5 years ago and the fridge has always worked well, but it did struggle last summer in 100 outside and 90 inside temps.

In the past few months I have used the RV very heavily. It seems like the cooling capacity has gone down.

Right now it is 88 outside and 85 inside, the fridge is on setting 5/5 (coldest), and it is holding just barely at 39F. Freezer is -6F. On propane.

It recovers overnight in 45F ambient temps, going down to maybe 32F with same setting.

AC power is a bit better but not much.

Wondering if the R717 (ammonia) could be a bit low? I very much doubt it has ever been touched in 24 years.

Thanks for any suggestions.

[WesternHorizon]

SidecarFlip wrote:

2oldman wrote:
90 inside, ugh. No ac?

Sounds like a sweatbox to me....

AC on full blast all day. It was quite hot outside, 110F+, at 6500 feet elevation.

Welcome to the future of the west.

[SidecarFlip]

2oldman wrote:
90 inside, ugh. No ac?

Sounds like a sweatbox to me....

[NRALIFR]

The OP said in his first post “AC power is a bit better but not much“, which suggests that when more BTU’s are put INTO the cooling unit, it performs better. Of course later he said it was “basically the same” on AC and LP.

Replacing the cooling unit is the second most expensive way to “fix” your problem, but assuming a quality unit is correctly installed you can pretty much count on better performance than the one you have now. I’d at least look at the other possibilities first though. You might find that you have more than one problem that’s degrading the performance.

:):)

[dougrainer]

His symptoms are classic for a partially blocked cooling unit. This happens over years when you ran the refer off level occasionally and you never notice the degradation of cooling until you need it to operate at 100 percent when it is warm/hot outside. Since it does the same on 120 and LP, he probably has a partially blocked cooling unit. Doug

[garyemunson]

Is the fridge in a slide? If so, it probably came with a factory installed muffin fan or two to help exhaust hot air out of the top of the fridge bay. They quit and you will have that problem. The ammonia charge never "gets low" in absorption fridges. A leak will empty it within a day and it will be dead. These replies pretty much cover every base...

[NRALIFR]

Almot wrote:
If it's -6F in freezer, it doesn't look like propane regulator gone bad. When mine had gone bad, it could barely keep 40 in FREEZER.

39 in fridge at 100 outside and 90 inside is pretty normal too. Especially when the sun is on that side. Check the fridge doors. Or slide that thermistor sensor on the fins up (or down, I don't remember).

It depends on how “bad” the regulator is. I replaced mine recently after noticing a drop-off in performance of the fridge cooling, particularly on LP. Here’s a link to the topic I posted about it.

Tech Issues Topic

:):)

[midnightsadie]

for that 90deg temp inside I think its doing a great job.

[Almot]

If it's -6F in freezer, it doesn't look like propane regulator gone bad. When mine had gone bad, it could barely keep 40 in FREEZER.

39 in fridge at 100 outside and 90 inside is pretty normal too. Especially when the sun is on that side. Check the fridge doors. Or slide that thermistor sensor on the fins up (or down, I don't remember).

[Old-Biscuit]

-6*F in freezer is great temp....but with temp setting on MAX COLD (5) food compartment temps should be cooler then 39*F
May have some blockage beginning to occur

Remove cover on lower circuit board in outside compartment
P2 connector....left side middle area ....2 WHITE Leads
Unplug the connector from circuit board......thermistor wires

Run fridge for at least 12 hrs on AC Element and recheck temps
W/O sensing from thermistor the fridge will run continuously
Temp in food compartment should get down to 32*F IF the food compartment High Temp Evap Coil is fully functioning


R717 is NOT used in absorption fridges ---used in straight concentrate form in compressor chiller units
RV Absorption is ammonia, sodium chromate, water & hydrogen gas (or helium in 2 no longer produced units) at 300 psi

Leak in cooling unit and NO ammonia/Hydrogen ....non-refillable

[2oldman]

90 inside, ugh. No ac?

[wnjj]

Make sure the door gaskets are good. Even a little air leak will cause a loss of cooling.

Close a dollar bill in the door and see how easy it pulls out. Try this all over the gasket.

[doxiemom11]

If you are not in the shade, that sounds pretty normal to me for the temps you have inside and out. The sun can make a huge difference. We found that our this past summer in NM - and if it's in a slide it's even worse.

[WesternHorizon]

Thanks but the LPG discussion doesn't explain why it is basically the same under AC power.

[enblethen]

I would not even spend the time on testing a regulator. Just replace it!

[NRALIFR]

Cleaning the burner and chimney is annual maintenance on an RV fridge. There is also a heat diffuser inside the chimney that should be checked. They tend to get the end burnt off of them over time. I would bet your LP pressure is low, though. You need a manometer to check it, either liquid or digital. If the LP pressure isn’t maintaining 11” of water column with the fridge running, you probably need a new LP regulator. As old as yours likely is, I wouldn’t even try to adjust it.

:):)