Refrigerator warms up when driving

[daytripper63]

I have a Dometic NDA1402 side x side refrigerator and anytime I travel it gets warmer, even when we don't open it. It does not matter if it is running on propane or if I run it on the generator. It does not matter if it is hot weather or cold. I just drove 107 miles in 76 - 85 degree weather and when I left outside temp was 85 and the refrigerator side was 33 and the freezer was 1 degree, when I reached my destination the refrig was 44 and the freezer was 21 degrees
I am in the air conditioning business and I have two temp probes so I can measure temps without opening the doors.
The frig is installed in the slide out and has the vents at both top and bottom to the outside, it also has two fans in the back to help dissipate the heat and they are both working.
Does anyone else have this problem and if so has anyone figured out how to solve it.

[daytripper63]

Update, I put a plug in the drain line to prevent warm air from going up the line when driving and the refrigerator and freezer both got warmer as usual when driving.
My trip was about 100 miles and temp went from 32 to 41 in the fridge and 1 up to 17 in the freezer, i think Doug is correct, I just have to figure out where the warm air is coming from when driving so now I plugged the drain hole from the inside of the freezer and the refrigerator and drove 17 miles in 84 degree outside temp (which is about 10 degrees hotter than my 100 mile trip home) And since I had to open the doors to tape shut the drain ports my starting temps were a bit higher 39.5 degrees in the fridge and 17.5 in the freezer. After 17 miles my refrigerator went up to 41 but my freezer temp dropped to 11 degrees so it looks like we are going in the right direction

[dougrainer]

Fiesta wrote:
My Bounder fridge (on the slide) got warm driving. Found kinked gas line hose when slide was in, OK out. Rerouted hose.

If the line was kinked, then the LP was probably not flowing and that would get a check light failure. The OP has no such failure code. Doug

[Fiesta]

My Bounder fridge (on the slide) got warm driving. Found kinked gas line hose when slide was in, OK out. Rerouted hose.

[dougrainer]

daytripper63 wrote:
Doug, the CU is original and I inspected the drain lines and do not see or feel any cracks or holes in the lines although I think I will replace them anyways soon. I put a plug in the drain line for the trip home and will see if that takes care of the problem. I was not aware that other rv fridges did not drain the same. If this works should I p-trap the drain line or do you have a better idea

If you look inside the freezer bottom you will see the drain hole. YES, always install the drain hoses with a P trap or loop. That way NO air can migrate back inside. IF you have the white plastic corrugated Dometic drain hose, from the age of the unit, that hose is probably brittle and leaking. Use regular rubber/clear type drain hose for replacement. Doug

[daytripper63]

Doug, the CU is original and I inspected the drain lines and do not see or feel any cracks or holes in the lines although I think I will replace them anyways soon. I put a plug in the drain line for the trip home and will see if that takes care of the problem. I was not aware that other rv fridges did not drain the same. If this works should I p-trap the drain line or do you have a better idea

[dougrainer]

daytripper63 wrote:
Thanks Doug, I suspected bad air over the top and bottom vents when driving since my awning arm sticks out about 3 inches and is about 5 inches in front of the two vents which would creat a lot of turbulence. So last night I got out the ladder and removed the upper vent cover and there was a lot of heat up there but the factory fans were not running so I installed a jumper wire to make the fans run constantly and the refrigerator cooled down faster the usual and I will see how it does on the way home tomorrow.
P.S. I almost went residential fridge a few weeks ago since it stopped working on me but I figured while I was pulling it out I much as well try turning it upside down before just replacing it and it started working again. I already did all the measurements to see what would fit but since it started working again I figured I would save my money for the moment.
Thanks I will let you know if it keeps temp better with the fans on, if it does I might relocate the fans up to the grill.

You are confusing the operation of the refer with your problem. LACK of ventilation or a air flow problem will NOT cause such a drastic interior temp rise after driving a few hours or even all day. Your problem is the refer is pulling in outside air. There are 2 ways for the refer to do this. The 1st is what I stated earlier. The 2nd(if the CU had been replaced) would be inadequate CU to the box sealed correctly. If it is the original CU, then this is not the case. IF the CU has been replaced, then this may be the case. On a correctly functioning RV refer you could turn it OFF and drive and probably have negligible temp rise in transit especially 20 degrees in the freezer. Remember, YOUR model is a rarity in that the Freezer has an outside egress for drainage of water and 99% of RV refers the freezer has no such hole. Doug

[chuckftboy]

I have also been in the refrigeration and air conditioning industry for a very long time and I think Doug nailed it. If the inside of the coach is at all negative going down the road, a lot of hot air will come in through a drain hose.
That one of the reasons there is a P-trap on your home a/c.

[daytripper63]

Thanks Doug, I suspected bad air over the top and bottom vents when driving since my awning arm sticks out about 3 inches and is about 5 inches in front of the two vents which would creat a lot of turbulence. So last night I got out the ladder and removed the upper vent cover and there was a lot of heat up there but the factory fans were not running so I installed a jumper wire to make the fans run constantly and the refrigerator cooled down faster the usual and I will see how it does on the way home tomorrow.
P.S. I almost went residential fridge a few weeks ago since it stopped working on me but I figured while I was pulling it out I much as well try turning it upside down before just replacing it and it started working again. I already did all the measurements to see what would fit but since it started working again I figured I would save my money for the moment.
Thanks I will let you know if it keeps temp better with the fans on, if it does I might relocate the fans up to the grill.

[bullydogs1]

My coach has this same fridge in the slide...I mounted an exhaust fan in the top vent to pull air thru and it runs whenever on electric and I plugged the hole in the bottom of the freezer and it has helped tremendously.

[Ivylog]

Sorry, but I solved the same problem by going residential. NoCold 1200 not in a slide... factory two fans plus I added a third... all on a manual switch. Amish cooling unit, ARP control. Worked OK until three years ago when it became borderline while parked on a hot day. Unit started warming while traveling on both propane and elect. Plugged drain line and filled with water to check for broken line. Ran all three fans. Mounted scoop on outside vent to force more air in... nothing helped. Got tired of throwing good money in a bad product.

Found a 21 CuFt residential refer that came within 1/2" H of fitting. Added 4 AGM batteries, 1000W PSW inverter and 100A charger to power it and my Sat/DVR/TV because we boondock often.. Years ago I lowered the house battery rack making room for another rack and 4 more batteries. The 4 new batteries went in the engine area... two next the the two engine batteries and two over the transmission. You can find my DIY install here.

If you do not boondock often then you do not need more batteries for a residential as the engine 160Amp alternator is capable of producing the 8 amps need to run it off your inverter when traveling. Yes, 8 amps... 96 Watts.

[Mr_Mark1]

DSDP Don wrote:
I have to say that I don't always agree with "dougrainer", especially when it comes to changing over to a residential refrigerator, but in this situation I think he's right. His statement is not in his character, but I'm guessing he got aggravated. Not everyone has the room, money or camping style (boon docking) to change over to a residential refer. Some RV's are just to small to do it.

With that said, let's keep in mind that every time "dougrainer" comes on here, the OP is basically getting a free diagnose or "service call".

When I read this post, it wasn't the typical post about a refer not cooling. The OP documented exactly what was occurring with times and temperatures. I knew immediately it wasn't a fan issue and had no idea what might be wrong. My next thought, "dougrainer" needs to show up and he did. His diagnosis sounded spot on.

I think for the sake of free "service calls", we should respect his posts and keep him returning here for as long as we can!

No sucking up, just trying to keep a valuable resource around.

X2


I know it's easy to get irritated, we all have. At the end of a day, just let it roll off like water on a ducks back. 🙂

[lap527]

We have had same problem for 3 years. Our fridge works great parked. 2 weeks ago left home it was 30 degrees got to Chatanooga it was 54.6. Our temps rise 2.5-3.0 degrees per hour while moving. DH thinks a vacuum is being created by our front jacks so the lower vent can't pull in air. DH did make a plexiglass cover that covered half of the lower air vents and it did help. When we park we have to remove it. It is so frustrating. In addition we bought a 5day cooler. Some folks put ice in the fridge to keep temp down, others just pack cooler until they get to their destination. Personally, I am over it. It's just too aggravating. Good luck!

[DSDP_Don]

I have to say that I don't always agree with "dougrainer", especially when it comes to changing over to a residential refrigerator, but in this situation I think he's right. His statement is not in his character, but I'm guessing he got aggravated. Not everyone has the room, money or camping style (boon docking) to change over to a residential refer. Some RV's are just to small to do it.

With that said, let's keep in mind that every time "dougrainer" comes on here, the OP is basically getting a free diagnosis or "service call".

When I read this post, it wasn't the typical post about a refer not cooling. The OP documented exactly what was occurring with times and temperatures. I knew immediately it wasn't a fan issue and had no idea what might be wrong. My next thought, "dougrainer" needs to show up and he did. His diagnosis sounded spot on.

I think for the sake of free "service calls", we should respect his posts and keep him returning here for as long as we can!

No sucking up, just trying to keep a valuable resource around.

[dougrainer]

The NDA 1402 has 2 drain tubes for the evap fins. In the bottom back wall of the freezer side is a drain hole. Below the refer side evap fins is a drain pan and that also has a drain tube that goes out the back of the refer. They both combine to a T fitting with one drain hose. So, odds are from 8 years old refer, that white plastic drain line has deteriorated and you basically have a hot air egress into both sides of the refer. When in transit, these open hole/s will be sucking in hot air. Check those drain hoses. Also, if the hoses are in good shape(I doubt it), plug them off and then do your next test drive. This is the most common cause of temp rise in a Dometic refer while in transit. Doug