Refrigerator not working on AC - ok on Propane

[wadingthroughlife]

Hey all, 

 

The RM 2400 in our 87 Sunrader doesn’t seem to be working on electric/shore power. 
 

The propane option seems to work fine. 
 

I’m not entirely sure if it works on 12v or how to check. 
 

I’m also not sure how or what to check on the shore power side for the fridge. All other functions seem to work on shore (water pump works faster, rooftop AC unit works..) 

 

I think this has been an issue for the last few trips in retrospect. I’d been using frozen gel ice blocks like you’d get in a delivered meal kit to aid in quicker cooking before a trip, then going to 12v in route, and gas when boondocked. I can’t say for sure if it’s been working on shore power for the last few trips. 
 

Any help is majorly appreciated, as we’re headed on a trip this weekend where we’ll be plugged in. I can run on gas if needed but I didn’t want to burn it all pre-cooling. 
 

 

Thanks in advance!

[wadingthroughlife]

I went back out, after checking it on gas, and swapped back over to electric. I hear it trying to work on the inside of the fridge and inside the exhaust grate as well as feel heat coming off the burner now. Maybe it’s a finicky dial? 
 

No cobwebs or bug nests initially visible.
 

I’ll report back in the morning to let y’all know if it’s actually cooling or not. 

[WME]

There should be wires coming out of the boiler stack. You can trace them, unplug them and use an OHM meter to check for continuity. 40-100 ohms, if its open then you need a new heater element. 

The element failure is not uncommon.

[wadingthroughlife]

Thanks so much! (As usual)

[wadingthroughlife]

Seeking confirmation on this being the replacement part in case it’s what’s bad. 
 

 

https://www.rvpartscountry.com/MC-Enterprises-Refrigerator-Cooling-Unit-Heater-Element-Use-With-Dometic-Refrigerator-Models-RM2300-RM2400_p_39365.html

Edited July 27, 2023 by wadingthroughlife

[WME]

NOPE, that is a 120v ac heater..

Try this...https://www.amazon.com/MC-Enterprises-0173737016MC-135W-12V-Refrigerators/dp/B01DCWNLS0/ref=psdc_155287011_t3_B00T371JGU

Edited July 27, 2023 by WME

[extech]

he is looking for 120v

[wadingthroughlife]

So perhaps

 

MC Enterprises 0173756016MC Heating Element for RM2300/2400 160W-120V Dometic Refrigerators https://a.co/d/7dGndpw

 

 

Edited July 27, 2023 by wadingthroughlife

[linda s]

This is the 12 volt heater but not exactly sure if you need any of them. These refrigerators don't make noise when they are trying to work. 

Cooling stack either gets warm or it doesn't on each power source. 

Dometic 0173735010 Heater 125Watt 12Volt - RV Parts Express - Specialty RV Parts Retailer

Linda S

[extech]

either of the 120v  ones you listed will work. doubt that yours works just a little. usually go no go

[wadingthroughlife]

So is there a separate 12v heater vs AC heater? Or is the 12v one WME and Linda listed for the 3way vs 2way fridge? I’ll try to locate a manual too. 

I’ll do more troubleshooting tonight too. 

 

Thanks y’all. 

[linda s]

A 2 way will only have a 120 volt heater and a 3 way will have separate 12 volt and 120 volt heaters. If your fridge is original 

I'm sure it's a 3 way

Linda S

[WME]

Yes there is a seperate heater for 120v or 12v. You said running on 12v in your orginal post, thus the 12v heater element link.

FWIW the 12v is for maintaining cool, not cooling. The 120v heater is 325w and the 12v is 130w

Edited July 27, 2023 by WME

[wadingthroughlife]

10 minutes ago, WME said:

Yes there is a seperate heater for 120v or 12v. You said running on 12v in your orginal post, thus the 12v heater element link.

FWIW the 12v is for maintaining cool, not cooling. The 120v heater is 325w and the 12v is 130w

I see the confusion - sorry.

 

I'm not super concerned with the 12v portion, but rather the 120 when plugged to shore.

 

I noticed the fridge not cooling when plugged in to our shore outlet at home to pre-chill the fridge ahead of our weekend trip. I wiggled the switch and thought it started working, as it got down to 60 degrees and I felt warmth on the boiler stack. However, this morning it was back to 80 degrees.

 

• I'll test the ohms on the heat element as WME initially mentioned, but is that still looking for 40-100ohms if it's the 120v element?
• Is the 12v heater element obviously different than the 120v element in the boiler stack?

 

 

 

 

 

 

 

 

[Ctgriffi]

To answer your first question... If the 120V heater element is in fact rated for 325 watts, then you should be reading somewhere in the range of 44ohms on that element, plus or minus 10%.

Edited July 27, 2023 by Ctgriffi

[wadingthroughlife]

4 minutes ago, Ctgriffi said:

To answer your first question... If the 120V heater element is in fact rated for 325 watts, then you should be reading somewhere in the range of 44ohms on that element, plus or minus 10%.

The 2410 manual I've found online indicated:

 

AC Heating Element:

Amperage1.3

Ohm Resis. +/— 10% 92.3

Wattage160

 

 

AC COMPONENTS HEATING ELEMENT

To check a heating element, remove the heater leads from the terminal block and measure for proper resistance across the two leads.

You should obtain the following readings, plus or minus 10%

RM2410: 92

 

 

I dont see anything in the diagrams showing a separate 12v vs 120v heating element though. I need to physically look again, but alas at lunch at work.

[Ctgriffi]

Great, makes sense: if the AC element is only 160 watts (which sounds much more reasonable—my Norcold pulls about 170watts in 120V mode) then you're looking for an element resistance of ~90Ω.

Edited July 27, 2023 by Ctgriffi

[extech]

if you have  a12v heater also, there will be four wires coming from the stack. 2 for each heater

[wadingthroughlife]

3 hours ago, extech said:

if you have  a12v heater also, there will be four wires coming from the stack. 2 for each heater

Can you tell from this diagram if the heater is one unit or two separate? There are 4 wires. I just haven’t been able to take off the shroud and pull the elements. 
 

I do have proper voltage to the outlets box, but it was a little confusing on what to pull to check the continuity of the elements. 
 

Also, it seems like maybe, if this is possible, that I have an RM2400, not the 10? The manual says 2400 and I’m not sure where on the unit other than the face plate that matches, to check. 

Edited July 27, 2023 by wadingthroughlife

[extech]

yes they are 2 different heaters. one pair goes to 12v, the other to 120v.  the top picture is cut off, but should show where they go

[wadingthroughlife]

So I used an infrared thermometer and it was definitely warm on the boiler (maybe 95f as it’s insulated) and heating element (135f ish) but the fridge was a meager 68f, probably from the help of the ice blocks. It’d been running all day long on 120v shore.
 

Between checking it before bed last night at 60,  went totally back to 80f overnight.
 

I guess I thought the element would totally die not fizzle as was mentioned. I can lightly hear the system working from the back, but I wouldn’t really call it the death gurgle sound I’ve read about. 
 

I’m getting right at 120v at the fridge outlet, but I haven’t pulled the elements loose to check their connectivity. The board is also kind of nestled under a pretty inconvenient looking spot to check voltage there too. 
 

Here’s hoping the LP gas chills it overnight to prove it actually works overall. The temp on the insulated boiler stack is presently about 150f and close to 290 at the pilot light cover after a couple hours of running on gas. The whole system is running much hotter back there on gas than it was on shore. 

[linda s]

Is the freezer cold? If it is the fridge has a thermistor that can be adjusted. 

rv refrigerator thermistor adjustment - Google Search

Linda S

[wadingthroughlife]

10 hours ago, linda s said:

Is the freezer cold? If it is the fridge has a thermistor that can be adjusted. 

rv refrigerator thermistor adjustment - Google Search

Linda S

Well, it seems like maybe nothing is cold to be honest. Things seemed to be going the right way under my assumption the gas was doing the trick, but I did have the ice blocks in the fridge to speed things up still. I want to say last night it got down to mid 50s but back to 60 this morning. 
 

Does neither AC or Gas cooling lead toward thinking it’s the cooling unit? 
 

 

[extech]

i think it's toast. mine had leaked in the foam and never smelled. i think there are pictures here somewhere

[wadingthroughlife]

48 minutes ago, extech said:

i think it's toast. mine had leaked in the foam and never smelled. i think there are pictures here somewhere

Yippie, haha. Cooling unit or total replacement?

 

It's 2x the cost to replace, but is that genuinely worth it?

 

The Dometic 2-way (not sure 12v is really needed for our use) RM2351RB1f is about $1250 to the door presently at Camping World, but it seems no door panels are available (Could harvest from the old fridge for similar aesthetic). I'm also not sure how well the gas connection on a new fridge is going to line up, and there will be some minor shimming and trimming to do, since it's slightly smaller.

https://www.campingworld.com/dometic-americana-3-cu.-ft.-two-way-absorption-compact-refrigerator-right-hinge-108156.html

 

The cooling unit is about $600 with shipping/core/tax etc. I should probably do both heating elements too, as they seem to fall apart in repair videos I've seen. (Add $70 each for both the 12v and 120v) ~$750

I'm a little intimidated at replacing the unit, mainly getting all the bits back in the right place.

https://atcoamerica.com/products/cooling/#catalog

 

 

If both were the same price, what would all here do?

[linda s]

I had my cooling unit replaced the same year I bought my Sunrader. 2005? Still works perfect.

Linda S

[Scott iv]

If cost was the same I would go brand new. But know yourself. Are you able to disassemble the new fridge if needed to get it into your camper? Or remove parts of the camper to get it in? Or would having someone come get it in there and connected to the gas and dc be an additional cost. 

[extech]

i'm a fixer, so would definitely repair the old one cause i'm also cheap. either way you have to remove the old one.  not that hard- remove fridge door, disconnect lines and wires, remove mounting screws, remove passenger seat, take it out passenger door

[Ctgriffi]

If you can find a decent size match, you could also try going the apartment-style or mini-fridge route. It will work on 120V AC only, of course, but you can also run it off the coach battery (or alternator) via a fairly inexpensive inverter. Not a great solution if you're a boondocker, maybe, but doable for other kinds of camping.

[wadingthroughlife]

Thanks yall. The deed is done. Want to keep this thing capable for boondocking and slightly modernize with less finicky controls. Going with the Dometic 2 way. 

[linda s]

Don't let Camping World put it in. They will over charge you and their reviews Atlanta suck. Back in the day when I was still

stupid, I went to the Camping World near my home and tried to buy some simple glazing bead for my windows. The service department 

didn't know what I was talking about even after I showed them. Told me I had to buy new windows. I found it myself in 10 minutes online. You can do this. Check YouTube for videos.

Linda S

[wadingthroughlife]

6 minutes ago, linda s said:

Don't let Camping World put it in. They will over charge you and their reviews Atlanta suck. Back in the day when I was still

stupid, I went to the Camping World near my home and tried to buy some simple glazing bead for my windows. The service department 

didn't know what I was talking about even after I showed them. Told me I had to buy new windows. I found it myself in 10 minutes online. You can do this. Check YouTube for videos.

Linda S

Ouch! I definitely intend to install solo. I'm hoping the toughest part is physically removing the old and then shimming and trimming the new one in. 

 

 

Thanks for all the help, all. I'll post about the install. I think I still owe a general posting about the rig too.

[Scott iv]

Unless you plan to try to resell the old, you can just do what it takes to get it out; disassemble up to and including sawzall. May just slide out the door after you remove the fridge door. The original 3 way fridge in my Escaper came out the door once i removed the fridge door and fridge door brackets. I may have had to remove the pilot light cover to but nothing too dramatic. 

[AtlantaCamper]

I'll throw a reply on this thread partly to say hi to wadingthroughlife because I'm also in an '87 Sunrader in Georgia (downtown Atlanta).  HI, you have a local person if you ever need hands on info/assistance.

on the general fridge issue, I replaced the cooling unit a few years back and I've been happy with it.  I only use propane.  It's just easier for me to not be switching fuel sources.  My 12v and 110VAC heaters do work, but I never use them.  It uses so little propane that it's not worth changing to AC imho.  So the cheap way to go about this is to just forget about the AC heater and just use it as it is on propane.  Is that a realistic option for you?    My impression from the quick review of the thread is that the fridge generally works on propane, just not on AC.  I had to take my heater core apart to get the 12v and 110vac heaters to work by making sure they had good contact with the ammonia boiler, which was a kind of pointless task considering I never use them now...

 

 

[wadingthroughlife]

Hi All, 

I am replacing the 3-way with a 2-way, but there’s still a 12v connection question I have on the new one for lights, board, and the fan it has.
 

I’m asking because there is a white and black wire coming down from the area above the fridge to the 12v cigarette plug? that had also connected into a molex plug of the old one aside from the 12v positive and negative that came from the front of the truck. Black from above was into the red from the truck battery. White was into a separate molex with the other white from the truck with the red. 
 

I’m not sure if I should or could tie those in to this new fridge. Or connect up to a different 12v supply while I have the chance. The fridge manual says not to run other outlets or appliances off the fridge. 

Old pic on top, new below

 

Thanks so much to everyone for the help. 

Edited August 12, 2023 by wadingthroughlife