Rm1350 refer not cooling

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Coopster8

Coopster8

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Joined
Dec 10, 2017
Posts
47
Hey all,
We are a proud owner of a 2009 keystone challenger, but we're finding out some little (big) problem. Our rm1350 isnt cooling.. the freezer is cold, but the refer is nicely maintaining 50 degrees, i checked the fans, they work, but never heard them come on. I drove it to the camp another camp site an hr away and guess what, it went down to 33? well in a couple hrs it was back to 50? .
Any advice/suggestion would be great
 
Clean the chimney?? How is this done?? Im sure i might find in youtube.
 
Climb up on the roof, take the top cover off.  Using a wire brush scrub the chimney.  Its just like a chimney sweep does for your home.  Follow by blowing all the debris out.  Carefully clean up the crud.  Before you start tape the burner orifice to protect it from being clogged.
 
Ok thank you, but everything i find on YouTube is if its not working on gas. I have put the thermostat outside to trick it, and it still don't lower in temperature below 50 or so, on gas or electric. I have put a fan on the back fins for a day and still don't drop. The freezer gets cold but the refer dont. I will clean chimney tomorrow, to see if that works. My chimney is dont go though the roof, since my refer is in my slide.
I have jumped the fans as well and ran for a day. The only time it stayed cool was going to new site. (33 degrees) i ran gas only, thinking its control board, still holds at 50 ?, 
 
That it cooled better while traveling is a pretty good indication of poor airflow. 

If the refer is installed in a slide there will be some luan panels to route the hot airflow out the side vents.  If that panel has come loose hot air could be pooling.

If it's not installed in a slide there may still be luan panels.

There will be a thermostatic switch attached to one of the fins on the cooling unit.  If it's not making good contact with the fin that could be part of the problem.  Are you sure the fan(s) are coming on?

Cleaning the chimney is good advice.  Anything, and we do mean anything that blocks the convection airflow is a problem.

Several people on here have added 12v computer fans to draw air through the system.  I'm one of them.  My 1201 LRIM is consistently 34-37F in the refer box and -18F in the freezers.  I used 4 fans and a 180F thermostatic switch to turn the fans on when needed.  My refer is in a slide.

Good luck with it.
 
I will install more fans and clean chimney today, also look for the luan panel as well, anything has to be better than what im doing now.. I will keep you updated on the status of the recommendations also the wind theory makes sense..
Hoping for the best
 
Ok.. 2 more powerful fans installed, i pointed them up towards the fins.. my refer is in the slide, but dont see any luan panel or anything that routes the heat out of my refer compartment. I by passed the thermostat on fins to see if that helps..
I work on chimney this weekend, but will keep you updated
 
From my experience trying to force air through the system is about half as effective as drawing it through with exhaust fans.  If you search on 'Muddypaws Mod' you find my old posts covering everything I did to my refer.
 
Another stupid question concerning my problem. The black tank on the cooling system, should it be warm to the touch, or hot to touch? Mine is hot to touch
 
The cooling unit uses heat to cool.  Yea, it makes no sense.  So yea it will be hot.  Again, like you have diacovered your issue is totally anmair flow issue.
 
Ok, i have been running new fans for about 5 hrs and no change, still 54 ? ill see in the morning, im currently running 2 3600rpm 1amp fans, i figured in 5 hrs it would of dropped some..
 
It should be VERY hot!  Like barely able to put your hand on it for more than a second or two.

Well DUH on my part!

If you're running on AC power it may be that one of your two heating elements has gone bad.  It's a simple matter to test them with an ohmmeter.  Check your manual for the proper resistance.  They're not horribly expensive or hard to replace.

This also would explain why it cooled better while traveling.  It's running on propane then.

See page 16 of this manual : https://www.manualslib.com/manual/766001/Dometic-Rm1350.html#manual
 
The boiler tank operates at about 350 F., so yes it should be extremely hot and the vertical tube above it also, though decreasing with distance.  The rest of the tubing on the return side should only be warm.

Muddypaws may have hit on the problem, i.e. a bad AC heater.  The RM1350 uses two 120v heaters in series, so in some failure modes you can lose heating capacity and cooling efficiency drops.  That would explain why it cools well on propane but not so well on 120v electric.  Try it on LP at the campsite and see how it performs.  If LP always works well, you can be confident that air flow, fans, etc. are all working as designed and that the problem is in the AC heater components. Note that low AC voltage to the fridge or a poor wire connection in the 120vac heater circuit would have the same effect.

http://bryantrv.com/docs2/docs/Service%20Manual,%20RM1350.pdf
 
Oms checked it and reading good, so now have it on l.p. for the night and see how it does.. crossing fingers
 
Did you verify the voltage at the element as well as ohms? There isn't much electronics between the RV's 120v outlet and the heater elements, basically just a relay that turns power on/off, but its conceivable there is a low voltage problem.
 
Still nothing, I oms checked heating elements, and it read 37.. which is good.. I'm going to more fans to exhaust today, instead of blow and see if that helps.. I want to thank everyone trying to help me troubleshoot this problem.. sounds like a air movement issue but it's just not bring it down any.. maybe ill just keep drive around to keep temp down..?
 
Yes, have even changed it.. 1st thing i did.. checked volts on elements.. 119.9 v? forcing air out now.. let's see how that goes.
 
Rather than shotgun the problem with more fans, run it in LP gas mode for a day. If it cools ok in LP gas mode, then air flow is not the problem and you need to look elsewhere.  Ditto with the thermister - same one is used whether electric or LP. 
 
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