Dometic over cool solution

[SteveJ]

I have a 3 year old Dometic fridge without 12 volt operation, hence no thermostat. I've tried moving the thermistor around to adjust the temp with little success.

I ordered an Inkbird 12 volt thermostat.
https://smile.amazon.com/dp/B019I3YC..._0bI9Eb7VT3CDK

I use it to control the main power to the fridge, cutting power when it reaches 32. I set the temp differential at 2 degrees so it comes on at 34.

Wiring comes in through the drain hose.

It has worked well with ambient temps ranging from 38 to 99. Power consumption is .7 watts when engaged for cooling. Less when not cooling plus the fridge circuit board is not drawing any current.

Precise temp control for $15. Works for me.

[peteco]

Originally Posted by SteveJ

I have a 3 year old Dometic fridge without 12 volt operation, hence no thermostat. I've tried moving the thermistor around to adjust the temp with little success.

I ordered an Inkbird 12 volt thermostat.
https://smile.amazon.com/dp/B019I3YC..._0bI9Eb7VT3CDK

I use it to control the main power to the fridge, cutting power when it reaches 32. I set the temp differential at 2 degrees so it comes on at 34.

Wiring comes in through the drain hose.

It has worked well with ambient temps ranging from 38 to 99. Power consumption is .7 watts when engaged for cooling. Less when not cooling plus the fridge circuit board is not drawing any current.

Precise temp control for $15. Works for me.

Hi SteveJ,
Could you make a simple wiring diagram of your setup. Thanks.

[mkguitar]

yes details, diagram !


we have the 1,2,3,4,5 type temp selector and a better control to cease changes of overnight freezing would be great !


( I use the drain hose hole for the wiring to my internal circulation fan)



mike

[SteveJ]

Here is a diagram that is posted up at Amazon but pay no attention to the Earth wire and the neutral is 12v negative.



For operating the fridge disconnect the 12v supply at the connecting block on the fridge and route it to and connect as shown in the diagram to the far left terminal(circuit board power) and also to the cooling relay terminal set on the right. Run a ground wire as indicated from circuit board (-) to ground.

From the other terminal(far right) run a wire to the connector block of the fridge.

I mounted the control unit in the fridge, zip tied to the bottom of the top shelf covered with a plastic shield to prevent liquids running into it.

Do note that all of the indicator lights will go dark when there is no call for cooling as power is cut the fridge circuitry.

The rating of the relays is only 10 amps at 12 volts so using it to control the electric heaters is not an option. It can only be used to control the circuit board power. Given this, if your fridge has a 12 volt heater it would be best to disable it so it is not accidentally activated as this would likely fry the controller relay.

If the controller does malfunction it can be easily rewired to bypass it.

I had about 4 months of use with it until I sold the RT, it performed perfectly.

I did put another unit on our Safari for controlling a fan for the outside coils this past May and it is working well. I've not had to install a control for our current fridge as the Dometic stuff is working OK.

HTH.

[fwdanielson]

That's a nifty solution. Does the Inkbird come with a temperature probe or do you have to mount the unit in the fridge? I couldn't quite tell from the Amazon description

[SteveJ]

Originally Posted by fwdanielson

That's a nifty solution. Does the Inkbird come with a temperature probe or do you have to mount the unit in the fridge? I couldn't quite tell from the Amazon description

It does come with a waterproof probe.

I zipped tied the unit to the bottom of the second shelf with a waterproof cover over it.

The wiring was strung through the water drain.