RV Fridge with No Temperature Controls

[JulieB888]

Hi all,
I just bought a brand new fridge for my RV, a two-way Dometic RM2351 and after I took it out of the packaging I realized that it has no temperature controls. It boggles my mind that Dometic would make a fridge without temperature controls because I know that my old fridge had to be turned way down n the winter and way up in the summer. The temperature controls were essential. Is this not the case with newer fridges?

The other thing is that it didn't come with a fan but the instruction manual says that it needs to have one installed. That makes no sense to me. Am I supposed to have a fan hooked up to my batteries? Won't it just drain them? I am hoping that the fan isn't really necessary. My old one didn't have it.

Thank you in advance for the feedback!

[JulieB888]

OK, so the fridge is finally installed but now there is a new problem. It seems to be draining my precious 12V power. I am full-timing off the grid so this is big problem. My old Dometic certainly didn't do that, but this one has fancy temperature controls which may be the problem. I have also noticed that it's not uncommon to hear it re-lighting the pilot light which apparently uses a lot of power. I know this because the other day my battery was low and the check light came on in front of the fridge; no matter how many times i pressed the power button on and off I couldn't clear it. All the other appliances worked, although the lights were kind of dim. Once I started the engine I managed the clear the check light.

Sigh. Are these fancy new fridges just impractical versions of the models? Has anyone else had this problem?

[Old-Biscuit]

Limp Mode

As suggested earlier by '2112' in his post
f the control can not read the temperature sensor and control the preset temperature, the control will run the cooling unit continuously at the energy source available

So either thermistor is not in clip on fin in food compartment, is not properly plugged into lower circuit board (P2) or is bad



HERE is an aftermarket fan kit.

Comes with 2 fans, mounting bracket(s), temp sensor (ambient air temp vs condenser fin temp), wiring, instructions etc.
And reasonably priced ----have seen them over $100


For illustration purposes only

[JulieB888]

I didn't see anything in the manual about installing a fan...that's why i say I have no idea where to even begin.

I think that I figured out why the DC wires that I used to connect to my old fridge weren't working. The negative was using the body of the vehicle as its ground, and the manual for my new fridge clearly says not to do that. Bummer. I guess I have to connect it directly to the battery then and route the wires though all the dangerous obstacle course of propane tubes, water connections, and storage bins.

[JulieB888]

Boy I really appreciate all the thought and effort you guys put into these responses. This new fridge is such a headache. It doesn't completely fit into the compartment where my old fridge used to sit, even though they are practically the same size, because the features in the back of the fridge don't fit into the curvatures in the compartment. Anyway, since I haven't fully installed it the top of the fridge has a 2 1/2 inch gap that needs to be insulated and the fridge door doesn't have a panel on it. Do you guys think that this things could cause the fridge to work in 'limp mode'?

[Old-Biscuit]

JulieB888 wrote:
No roof-vent so it seems the fan is necessary. I wouldn't have any idea of where to even begin with the fan and that thermostat.

As for the wiring, yes of course I plugged the positive into the positive and the negative into the negative. Yes two wires.

Circuit boards are sensitive to polarity....that is why I asked.

And w/o roof vent and being installed in a Roadtrek (curved wall) with lower/upper vents.......FAN required to improve draft flow.

Does sound like fridge is operating in 'limp mode'

[mkguitar]

I'd suggest that an $800 fridge- at this point is worth having a pro oversee the install.

at the very least to protect the warranty if there is an issue with the install/wiring etc which is affecting the operation.

Like others, I have read over the install instructions online and it seems pretty straight forward.
A basic understanding of how it works and what the fans do- how the venting helps or restricts operation etc is all in that manual

Mike

[2112]

From THIS manual I found this:

If necessary, adjust the thermostat by pressing the
Temperature selector button.
(RM2351, RM2451, RM2551, DM2652 &
DM2852: The temperature is controlled by a factory
preset temperature setting.)

It doesn't appear you have temperature adjustability but there is a thermistor connected to the cooling fins

The coffee freezing as you described indicates you are in Limp Mode. From the same manual:

LIMP MODE OF OPERATION
In the event of a failure of a major operating component, the control system will continue to operate the cooling system. RM2351, RM2451, RM2551, DM2652 & DM2852
If the control can not read the temperature sensor and control the preset temperature, the control will run the cooling unit continuously at the energy source available. The refrigerator will continue to operate in this mode indefinitely - or - until a new sensor is installed and the system reset.

I suspect either the thermistor is not in contact with the fin (the thermistor has to physically touch the cooling fin), the thermistor is not properly connected to the control board (P2) or the control board is not functioning properly.

As far as the fan you mentioned is concerned, this fan helps cool the external coil during hot summer months. Yes, it is advised to install this fan but lacking this function is not causing your coffee to freeze. The fridge is continuously running, over cooling the compartment.

Good Luck

[JulieB888]

But neither is the fridge in a slide out. Its in a Roadtrek van. But there is no roof vent, only an upper and a lower vent

[JulieB888]

No roof-vent so it seems the fan is necessary. I wouldn't have any idea of where to even begin with the fan and that thermostat.

As for the wiring, yes of course I plugged the positive into the positive and the negative into the negative. Yes two wires.

[Old-Biscuit]

Old fridge DC wires........just 2 wires?

Have you verified which wire is POSITiVE and which wire IS NEGATIVE?

Did you connect them POS to positive terminal and NEG to negative terminal on fridge?

The FAN is not complicated.......you removed and installed another fridge you can install connect a fan

BUT as I stated earlier.....if you have ROOF VENT and fridge clearances are correct you should NOT need the fan.
FANS are used when fridge is installed in slide outs

[JulieB888]

Now there's a new problem. I have 12V wires meant for my old three-way fridge. When I insert them onto my new 2-way fridge and turn it on and press the auto button which should make the fridge work on 110V it begins to make a clicking noise and it doesn't go away. HOWEVER when i take some wires and connect them directly to my battery and then to the fridge it works just fine. I would just leave it hooked up directly to the battery but the wires would have to be sitting next to propane line and city water connection and be passing through a storage unit on their way from the fridge to the battery. It seems pretty unsafe. I just cant understand why my 12V wires meant for the fridge make it behave that way.

[JulieB888]

Christ, that sounds like something you need to get a professional to do. I don't know why the fridge didn't just come with a fan built in

[Old-Biscuit]

JulieB888 wrote:
Wow thank you Old-Biscuit! That's actually the manual specifically for my model. The manual that came with my fridge was for dozen other models.

I have a lower access panel and an upper vent. But the sort of fan that you're talking about, the kind that is integrated into the fridge, sounds like it would be difficult to install. Where would i get it? Does it have a specific name?

If you have a 'roof vent' and fridge is installed following the required clearances then you shouldn't need the fan.

Installing fan/thermostat control/wiring/cut off switch are best done prior to installing fridge.
Can be done after install but fan location would have to be elsewhere

12V DC computer fan is better than the OEM fan

Thermostat is available on line (Dometic #3104133.016 On at 130*F fin temp Off at 115*F fin temp.... LINK

[dreed]

I don't like the idea of the new one. I do use the 12 option once in a while. I like the idea of the refer I have being simple. No ignitor board, something else to go bad. Also it needs 12 volts for the board the one I have now doesn't use a board. I hope mine lasts a long time......
Dave 04 Excel td