Failed '95 Dometic gas/elec Select switch - Solutions?

[Crank]

Sometime in the last year the Dometic RM2310 in my '95 Roadtrek Pop. stopped working on both 12v and 120v: it still works on propane. I am told by the service shop that the complex power source selector switch has failed: this diagnosis needs to be verified, there are other possibilities, I think. The complex replacement switches are no longer available from Dometic. I can limp along on Propane for a while, but I really value the 3-way power option.

I am wondering if it is practical (and advisable) to bypass the rotary switch which chooses between these functions for the 12v and 120v power sources, adding toggle switches (one would have to be careful not to have more than one power source on at once.) I have the wiring diagram.

I have already spent too many $$ fixing unforeseen problems on this RV to want to replace the refrigerator, unless a new one offers substantially better cooling in all modes.

My Dometic IS pretty anemic: if I got mine running again, fully serviced, and made all the improvements to it suggested by Red Rover*, I doubt it's performance would be that that much improved. (It gets up to 115*F here in S. NM, and although I head to cooler climes to camp, everything will likely be thawed by the time I arrive, and won't refreeze.)

One of Red's suggestions is to add an outside air scoop to create a ram effect to improve cooling. At what outside air temperature would this device become detrimental? I doubt 115*F would be helpful.

And is this mod. safe if cooling with propane while driving?) Some people never use propane while driving, suggesting at least a perceived risk.
* http://www.davewhitmore.net/RTModsImprovements%20to%20our%20Roadtrek%20190%20P opular%208-20-12.pdf

Dometic offers the RM2351 as a replacement for $600 + $150 shipping + installation, but I don't know if it cools any better than the one I have. Anyone familiar with it?

Is there something better? Must be absorption type, and run on at least 120v AND Propane. (The unit dimensions are about 29-3/4" hi x 20-1/2" w x 21-3/8" deep: no room fore something larger).

Perhaps this inquiry should be posted on a more general RV forum, if there is inadequate response here. (Not that in my experience Class B Forum folk lack in good suggestions!!! )

Thanks for any suggestions for repair or replacement.

[markopolo]

Re: the part - it would look something like this: Dometic Refrigerator Switch RM2410-2810 - Electrical Components - Refrigerator Parts - Refrigerators - RV Appliances

That's what I find for my 2410. This site - Laurelhurst Distributors Parts Breakdown - Dometic Refrigerators - seems to show the same part # for a 2310. It costs a bit too much to buy without visually confirming that it would fit.

[hbn7hj]

My suggestion is to replace it with an RM2354 3-way. You may need the door reversal kit and may have to change the DC wiring to handle 20 amps or so. The new one takes DC power (.5 amp?) to work so you need to allow for that. A 30 amp relay in the heater circuit controlled by alternator output would be convenient. No need to change anything when stopping for gas. You would have to do those mods yourself.
Harry 2003 C190P with an RM2354

[Crank]

hbn7hj, why do you suggest buying a new refrigerator (for over $800 shipped, door reversed, and installed)? Is it a significantly more efficient unit? That would be the only reason to upgrade, as I stated in my OP (unless the present problem is irreparable at reasonable cost, or not at all, of course). My present unit is 3-way so I should not need the wiring changes you mention.

I'd like to acknowledge a good suggestion, but I don't follow "A 30 amp relay in the heater circuit controlled by alternator output would be convenient." Which heater circuit [there are 2 in the refrigerator]? The alternator is only running when driving, and then it is powering the coach batteries, so how would this be useful?

My question was really about feasibility of bypassing the rotary mode switch IF it is really the problem and cannot be fixed.


MarcoPolo, thanks for the switch part number lookup and source suggestions. I did not find the exact right version in stock (2007432004B), but you are right - expensive!

[hbn7hj]

([QUOTE=Crank;49563]hbn7hj, why do you suggest buying a new refrigerator (for over $800 shipped, door reversed, and installed)? Is it a significantly more efficient unit?)

No, it is not a more efficient unit. The present one is old and could fail anytime from internal corrosion. May as well accept it and replace it. (Just an opinion)

You put a relay in the DC heater circuit so that when the alternator is off the relay is open. Otherwise every time you stop you have to go to the back and turn the refrigerator off to stop the high DC current drain.

You could bypass the switch. I would rather have a refrigerator that works like it is supposed to.

The downside of the new refrigerator, other than cost, is that it draws current to run it's computer even when it is on propane.

I wired mine so that the refrigerator can get power with nothing else connected.
Harry

[hbn7hj]

I live in Phoenix where 115F is not unknown. I have had the refrigerator box get above 50F but I have never had the freezer get above freezing. Maybe your old unit is not cooling as well as a new unit.
Harry

[eric1514]

Originally Posted by hbn7hj

...
You put a relay in the DC heater circuit so that when the alternator is off the relay is open. Otherwise every time you stop you have to go to the back and turn the refrigerator off to stop the high DC current drain...Harry

I took your suggestion you made a few months ago and did this.

http://www.classbforum.com/forums/f2...gain-5596.html

One of the most useful mods I've done.

[mkguitar]

sorry, my eyes glazed over at the post- did you check all the fuses?

my dometic has a fuse on the back side of the black plastic electrical box which is not easily seen.

are you sure that you are getting power?

Mike

[mkguitar]

Originally Posted by hbn7hj

I live in Phoenix where 115F is not unknown...

i have written on modding mine with extra fans and can count on 60F cooling below ambient on propane or AC power in the lower fridge portion parked here in phx.

freezer always freezes.

with the manual in hand check the internal sensor location on the fins, check the gas portion ( stack) is clean, clean electrical connections for full power to the fridge.

i have 3 fans on the external cooling fans- 2 wired to a switch, a 3rd wired to a heat sensor. and a small fan internal to the fridge

Mike

[JohnnyFry]

Judging from the reference in the MarcoPolo reply, it is a rather good switch design. It is of open construction so you can take it out and analyze how it works (or repair it as it could be dirty contacts). It ad that MP referenced indicated that the switch is available from 3rd parties.

As to the fridge efficiency; hot temps definitely take a toll but, even a good flow of 115° air will help because the condenser temp is hotter than that. Also, do your best to insulate all sides/top/bottom of the fridge and take care to plug air leaks from the hot side around the case of the fridge. I use AL metal duct tape for this job.

[WJones]

I'm a bit surprised that both AC and DC contacts in the switch would go bad at the same time. If the circuit diagram I'm looking at is correct, your unit uses a single thermostat for both AC and DC. If the thermostat fails, both of them would stop working at the same time.
The problem should be troubleshooted further to determine the exact problem: either a faulty thermostat or a defective switch. As mentioned previously, if it is the switch, perhaps it can be repaired.
William

[Crank]

Thanks for the many informative responses: I apologize for not acknowledging them before: I am not receiving notifications for some reason - do I have to subscribe to a post I initiated??? My preferences are set to receive them.

I have decided to take hbn7hj's advice and buy a new RM2354, in view of the age of the old one.

I have been thinking about the many complaints that Dometics don't cool well. I have not used the one I have: I am renovating a 1964 RoadTrek Popular, and I don't know how well the current reefer cooled.

I would not be surprised if they don't cool well in that model RoadTrek, because it only has one vent, and that is at the bottom of the reefer. There should be one at the top also, because heat rises and there is a lot of dead space for it to accumulate in.

Moreover it requires two vents for proper air circulation, one taking outside air in and the other exhausting hot air and that flow is likely to be sluggish. I plan to add the second vent, and any baffles that are necessary, and also install an extractor fan on the top vent to create a much more aggressive air flow, and better cooling. I may also add a smaller fan that draws outside air from the lower vent, and directs it across the cooling fins.

People who have added circulating fans often report excellent results, but they never say if they have dual vents: I expect that those who are the happiest with addition of a fan do have dual vents.

[BBQ]

Originally Posted by Crank

Thanks for the many informative responses: I apologize for not acknowledging them before: I am not receiving notifications for some reason - do I have to subscribe to a post I initiated??? My preferences are set to receive them.
::

Check your spam mail folder.

[RicaIii]

Hi...i am a new user here. As per my knowledge the new one takes DC power to work so you need to allow for that. A 30 amp relay in the heater circuit controlled by alternator output would be convenient. No need to change anything when stopping for gas. You would have to do those mods yourself.