Refrigerator not getting cold enough

[Davis]

I have a Dometic RM3804 in my 91 34ft trailer. I have owned the trailer for 9 years and have had issues with refrigeration performance the whole time but this past weekend was by far the worst.I actually had to throw out the contents when we got home due to spoilage.
The refrigerator works fine in cooler temps but suffers during the summer.

The ambient temp was around 95 deg outside and the fridge was on 50-55deg and the freezer was 15 deg .

Things that I have done in the past to help with this are installing a roof vent exhaust fan and install a 12volt fan in the fridge that attatches to the coil to circulate the air .These two things seemed to help last year but not this year.Also I replaced the circuit board last year as well.

Is it possible that the cooling unit needs to be replaced ? I hate to replace the entire refrigerator due to having to modify the cabinet unless if that is the best solution. Any suggestions would be appreciated.

[slowmover]

Subscribed. Look forward to how a 21-yr old reefer can be diagnosed, maybe fixed. I had questions about the one in our '83 SS but sold it prior to a go-through.

Is the airflow from bottom to top still "strong"? Sealed sides, all that, done previously?

.

[Inland RV Center, In]

Originally Posted by Davis

I have a Dometic RM3804 in my 91 34ft trailer. I have owned the trailer for 9 years and have had issues with refrigeration performance the whole time but this past weekend was by far the worst.I actually had to throw out the contents when we got home due to spoilage.
The refrigerator works fine in cooler temps but suffers during the summer.

The ambient temp was around 95 deg outside and the fridge was on 50-55deg and the freezer was 15 deg .

Things that I have done in the past to help with this are installing a roof vent exhaust fan and install a 12volt fan in the fridge that attatches to the coil to circulate the air .These two things seemed to help last year but not this year.Also I replaced the circuit board last year as well.

Is it possible that the cooling unit needs to be replaced ? I hate to replace the entire refrigerator due to having to modify the cabinet unless if that is the best solution. Any suggestions would be appreciated.

Does the inadequate cooling happen on LPG or electric?

Andy

[Davis]

The cooling problem is on both LPG and electric but seems worse on LPG.

The cooling unit was replced bt previous owner back in 2000.

There is no blockage in airflow at the bottom access door or the roof vent. Although there is alot of open space in the cabinet behind the refrigerator in this trailer which some owners say could cause problems.

[Inland RV Center, In]

Originally Posted by Davis

The cooling problem is on both LPG and electric but seems worse on LPG.

The cooling unit was replced bt previous owner back in 2000.

There is no blockage in airflow at the bottom access door or the roof vent. Although there is alot of open space in the cabinet behind the refrigerator in this trailer which some owners say could cause problems.

The cooling should be the same regardless of the heat source. However, if the LPG pressure is low, or the burner orifice is partially clogged, then the cooling in the LPG mode would be less than the electric mode.

That is also assuming that the reefer was level, if not, then that can cause the same poor cooling.

If you have done everything by the book, then not what you want to hear, but the cooling coil is kaput.

Andy

[Davis]

Originally Posted by Inland RV Center, In

The cooling should be the same regardless of the heat source. However, if the LPG pressure is low, or the burner orifice is partially clogged, then the cooling in the LPG mode would be less than the electric mode.

That is also assuming that the reefer was level, if not, then that can cause the same poor cooling.

If you have done everything by the book, then not what you want to hear, but the cooling coil is kaput.

Andy

Thanks Andy,
I did adjust the regulator last year to 11 psi and that made a difference in the burner flame but still not cooling good on either power source.

If I wanted to replace the entire refrigerator unit is there a model available that would not require modifying the cabinet ?

[TouringDan]

Andy

By kaput, do you mean that the coil has lost its ammonia charge? If that is so, then I would think that it would not cool at all. If there is not a leak then there is ammonia in the coil and it should work. If there is a leak, then all the ammonia will leak out so there can be no refrigeration, I would think. I am not sure that there is not an air flow problem.

Davis

I would operate it on electric, and do some temperature measurements and look at an airflow problem.

15 degrees in the freezer sounds fine to me, but 50 is way to warm in the fridge.

I have had issues with my fridge also. Warm weather is tough. Mine works fine sometimes and other times, not so well. I just returned from 4 days of boondocking, and it worked fine. I checked the temperature one time and it was 37 degrees. The cream for me coffee was fine and the beer was cold. No need to buy ice. I did not check the freezer temp.
Good luck. You are not alone.

Dan

[azflycaster]

The RB2820 is very close according to this chart:
http://www.google.com/url?sa=t&rct=j...8ZW66Q&cad=rja

[ventport]

I would take off the top roof vent and look down the hole. In my 1964 Avion the factory riveted a screen on the inside of the trailer under the air shoot that ducts the warm air to the roof vent. The screen was about 90% plugged when I finally found it. I removed the screen and my 48 year old fridge works just great now.

[Davis]

I did remove the roof vent when I installed the exhaust fan. The screen was clear. I have even had a small electric fan at the bottom to push the air but that did not solve the problem.
At one time I was told that Airstream had too much dead air space in the rear of the fridge unit and that it would not vent properly that being said it would not matter whether or not I replaced the cooling unit or the refrigerator but there again I am not sure on that theory either.

I do know that it operates ok in cooler months and suffers greatly in the summer. It will maintain temps below 40 in the lower section when the ambient temps are below 85 deg.

Any ambient temp over 85 deg the refrigerator starts to get warmer in the lower section. All doors close good and door gaskets are intact. Have even tried the dollar bill drag technique and there was no problem.

Is there any way to check the cooling unit for flow problems ?

[mjdsquad]

I have a similar problem in that my unit cools fine on electrical, however on LP it starts to warm. Is there an adjustment for the LP burner on these systems?

[Davis]

Originally Posted by mjdsquad

I have a similar problem in that my unit cools fine on electrical, however on LP it starts to warm. Is there an adjustment for the LP burner on these systems?

Last year I had to adjust the regulator at the propane tanks to increase the pressure to 11 psi.and that helped the flame be a little taller.

[DKB_SATX]

Originally Posted by Davis

Last year I had to adjust the regulator at the propane tanks to increase the pressure to 11 psi.and that helped the flame be a little taller.

Not to be intentionally nit-picky, but for future reference of people reading this thread, the gas pressure on the output side of our LP regulators is usually specified in inches of water, NOT psi.

11 inches of water is about 0.4 psi.

DKB

[Davis]

Originally Posted by DKB_SATX

Not to be intentionally nit-picky, but for future reference of people reading this thread, the gas pressure on the output side of our LP regulators is usually specified in inches of water, NOT psi.

11 inches of water is about 0.4 psi.

DKB

My mistake . Sorry about that.

[Inland RV Center, In]

The LPG regulator should be set to 11 to 13 inches of water column pressure.

The somewhat higher setting works much better when traveling in mountains.

Particles of rust can float around in the reefer tubing system, and then find a small orifice to block or partially block, which then has a negative effect on the reefer's cooling ability.

2 door reefers have 2 separate coil systems, therefore one can work correctly and the other one not.

Andy

[mjdsquad]

Thank you for the excellent recommendations. I will check the vents and ensure the lp regulator is set to 11 to 13 inches of water pressure, then run the refer on lp again.

[ventport]

How about taking the refer out and tumbling it? I have read this will sometimes fix them when they quit entirely, will tumbling help when they cool but just don't cool enough?

[Inland RV Center, In]

Originally Posted by ventport

How about taking the refer out and tumbling it? I have read this will sometimes fix them when they quit entirely, will tumbling help when they cool but just don't cool enough?

The "tumbling" may or may not dislodge the particle of rust that is blocking an orifice within the system.

Should it happen to work, that would be great.

However, when that same particle may cause the issue again, becomes a question of "WHEN".

Most likely, it will happen at the very worst time, namely on a trip.

Andy