I have a 3-way fridge (Dometic RML 8555) which has operated reasonably well for the last 2 years on 120 V or gas as long as the outside temperature was not above 90 degrees F. But in the last few months while still working normally when on shore power or stationary on gas operates poorly (on gas) or not at all (using the house generator for 120 V) when traveling. On gas, the fridge temperature will increase 5-10 F during a 3 hr. trip while on 120 V the fridge will increase 10-20 degrees during the same time period with outside temperatures in the 70's. Upon stopping, the temperatures will drop back to normal (35-40 F fridge) on either gas or 120V over a couple of hours.I have added an exhaust fan (130 CFM) in the condenser vent which does improve cooling while stationary but not during travel.I am looking for suggestions as to what would cause the fridge to operate normally when stationary but not while traveling. I am thinking about changing out the control board although I don't have any explanation on how the control board could cause this problem.Any suggestions would be appreciated.Mike

I'm not familiar with your exact model but if it has a vent on the roof, I would guess that while under-way the airflow over the roof is somehow preventing the normal convection airflow necessary to cool the tubes on the back of the fridge.

Travelin2 wrote:I'm not familiar with your exact model but if it has a vent on the roof, I would guess that while under-way the airflow over the roof is somehow preventing the normal convection airflow necessary to cool the tubes on the back of the fridge.This is a side vent installation and I thought the same thing - I was not getting proper air flow across the condenser. I tried adding an air scoop to the lower vent grill but that did not improve anything even though I know more air was entering the lower grill. Nothing has changed in the vent system or the fridge installation so it is hard to understand how the airflow would have changed in the last 6 months compared to previous 2 years.I cannot think of why the main control board would cause such a problem but I cannot think of anything else that would affect both 120V and gas.

mondmn70 wrote:Travelin2 wrote:I'm not familiar with your exact model but if it has a vent on the roof, I would guess that while under-way the airflow over the roof is somehow preventing the normal convection airflow necessary to cool the tubes on the back of the fridge.This is a side vent installation and I thought the same thing - I was not getting proper air flow across the condenser. I tried adding an air scoop to the lower vent grill but that did not improve anything even though I know more air was entering the lower grill. Nothing has changed in the vent system or the fridge installation so it is hard to understand how the airflow would have changed in the last 6 months compared to previous 2 years.I cannot think of why the main control board would cause such a problem but I cannot think of anything else that would affect both 120V and gas. If irc there should be no more then 1" between the back wall and the tubes, I would suggest you check this.

The condenser tube fins are less than 1/2 inch from the back panel of the fridge - is that the distance you are referring to? Nothing has changed on the installation or vent system since it was new (3 yrs) but this poorly operation when traveling has only occurred in the last 6-12 months. Any idea if the electronic control board could cause this kind of problem?

Refrigerator Issue | Good Sam Community

11 Replies

mondmn70
Explorer
Jun 09, 2016
I checked the condensate drain line and although I could not see it, I could feel the last 2-3 inches of it. The line was soft and flexible and appeared still be attached to the fridge - I could pull on it and it would stretch a little but seemed to be firmly attached.

However, there was no apparent "P" trap in the tubing in the amount I could feel and even if it has a trap in it someplace, I am not sure if the fridge is used enough that the trap would be full of water. So it is certainly a potential source of cooling loss for the fridge, but it's ID is only about 1/4 inch so not sure if the loss would be enough to account for the results I see. But it is easy to plug on the inside of the fridge to eliminate this as a possibility.

Thanks for the suggestion.
mondmn70
Explorer
Jun 09, 2016
WA4HTZ wrote:
Also, check the condensate drain tube which should be coming out of the lower vent. The cheap plastic tubing the manufactures use becomes brittle and breaks after 2 or 3 years and then you get warm air into the refrigerator. Go to www.rvrefrigeration.com (sorry, don't know how to post links yet) and look for a 3 part series of videos on replacing the condensate drain tube. These are very good. If you take the lower vent cover off, it is easy to tell if yours is cracked and falling apart. The bad news: you have to pull the refrigerator to replace it in most cases.

That is a very good suggestion. I have not checked the drain as a potential source of heat intrusion into the fridge, but it would seem logical that if this is cracked or broken, it would allow more air (heat) into the fridge when traveling.
mondmn70
Explorer
Jun 09, 2016
Dr Quick wrote:
Have you checked the "flame"? Sometimes dirt or scale can fall on the flame outlet and interfere with the flame. Make sure that it is working properly.
Also wind inside enclosure, could be interfering with flame. On my previous trailer I had to wrap come aluminum foil around flame enclosure, otherwise it would blow out when moving. The problem actually developed a few year after I got trailer.

I don't think it is wind interfering with the flame since I have the same result on 120 V (running the generator). The flame has a cover which would make it difficult to respond to wind but I could try wrapping the cover with foil to see if this improved the operation when traveling on gas.
midnightsadie
Explorer II
Jun 09, 2016
I though my flame was nice and blue and the right hieght ,BUT after cleaning the burn system it sure made a huge difference.
WA4HTZ
Explorer
Jun 09, 2016
Also, check the condensate drain tube which should be coming out of the lower vent. The cheap plastic tubing the manufactures use becomes brittle and breaks after 2 or 3 years and then you get warm air into the refrigerator. Go to www.rvrefrigeration.com (sorry, don't know how to post links yet) and look for a 3 part series of videos on replacing the condensate drain tube. These are very good. If you take the lower vent cover off, it is easy to tell if yours is cracked and falling apart. The bad news: you have to pull the refrigerator to replace it in most cases.
Dr_Quick
Explorer II
Jun 09, 2016
Have you checked the "flame"? Sometimes dirt or scale can fall on the flame outlet and interfere with the flame. Make sure that it is working properly.
Also wind inside enclosure, could be interfering with flame. On my previous trailer I had to wrap come aluminum foil around flame enclosure, otherwise it would blow out when moving. The problem actually developed a few year after I got trailer.
mondmn70
Explorer
Jun 09, 2016
The condenser tube fins are less than 1/2 inch from the back panel of the fridge - is that the distance you are referring to? Nothing has changed on the installation or vent system since it was new (3 yrs) but this poorly operation when traveling has only occurred in the last 6-12 months. Any idea if the electronic control board could cause this kind of problem?
grizzzman
Explorer
Jun 09, 2016
mondmn70 wrote:
Travelin2 wrote:
I'm not familiar with your exact model but if it has a vent on the roof, I would guess that while under-way the airflow over the roof is somehow preventing the normal convection airflow necessary to cool the tubes on the back of the fridge.

This is a side vent installation and I thought the same thing - I was not getting proper air flow across the condenser. I tried adding an air scoop to the lower vent grill but that did not improve anything even though I know more air was entering the lower grill. Nothing has changed in the vent system or the fridge installation so it is hard to understand how the airflow would have changed in the last 6 months compared to previous 2 years.

I cannot think of why the main control board would cause such a problem but I cannot think of anything else that would affect both 120V and gas.

If irc there should be no more then 1" between the back wall and the tubes, I would suggest you check this.
mondmn70
Explorer
Jun 09, 2016
Travelin2 wrote:
I'm not familiar with your exact model but if it has a vent on the roof, I would guess that while under-way the airflow over the roof is somehow preventing the normal convection airflow necessary to cool the tubes on the back of the fridge.

This is a side vent installation and I thought the same thing - I was not getting proper air flow across the condenser. I tried adding an air scoop to the lower vent grill but that did not improve anything even though I know more air was entering the lower grill. Nothing has changed in the vent system or the fridge installation so it is hard to understand how the airflow would have changed in the last 6 months compared to previous 2 years.

I cannot think of why the main control board would cause such a problem but I cannot think of anything else that would affect both 120V and gas.
Travelin2
Explorer
Jun 09, 2016
I'm not familiar with your exact model but if it has a vent on the roof, I would guess that while under-way the airflow over the roof is somehow preventing the normal convection airflow necessary to cool the tubes on the back of the fridge.