Optimum Fridge Cavity Temperature

[The_Breeze]

I built a set of thermostatically controlled fans to help move the air behind the fridge and out through the roof vent.

Does anyone know if there's an optimum temperature for within that cavity behind the fridge? I don't want the fans running needlessly 24x7 and hope for a balance between efficiency and practicality. Running fans 24x7 reduces their lifespan and needlessly draws down the battery (e.g. at night when it's cool).

Thanks.

I included pics below in case someone is looking for a solution and wants to consider this.

Measures 3.73"W(at widest point) x 24"L x .75"H - fits between coils and wall just above the bottom vent (only wall vent on my RV).

Fans, switch and thermostat purchased on ebay.

Positive wires marked with brown tape (weird setup)

PM me for more info if interested.

[Scubawise]

years ago on our little camper the tech installed a fan that if temp above 100 degress the fan kicked on and less went off

[Pete'sMH]

The one I installed only operates when the cooling unit is actively cooling. That’s the only time there is heat being produced that needs to be extracted. It’s not so much a function of how hot it is behind the fridge as it is of moving air (of whatever temp the air happens to be) over the coils that serve to dissipate the heat in the coolant.

[The_Breeze]

Thanks guys and you're both right. I just finished installing it and set it to 100 as Scuba suggested. It knocked the temp down 4d inside of 5min. I think this is going to work out. I put it together for about $10, maybe $11.

True test comes tomorrow in full sun.

[Bob Denman]

That looks like an outstanding solution.
Please let us know how the long term test works out.

[The_Breeze]

Mounted it last night. I'm amazed at the difference it makes. I think I'm gonna like this.

[Scubawise]

Looks great now you can survive in our old hometown Phoenix AZ..where the asphalt melts and you can fry an egg on the street

[Pete'sMH]

It looks like it will greatly restrict airflow though until the temp gets to your set point. My fridge heats the coolant up to about 180 degrees and needs it to cool down to about 90 before it enters the burner again. If you have reduced airflow you’ll be making it harder for the fridge to cool.

[The_Breeze]

Ok, I'll keep an eye on it. It tends to run all day during the day. It's 4PM, 96 in the shade, and the thermometer sensor sees 115 just on the other side of that board. That's up from 106 about 2 hours ago but it's stinking hot out there. The sensor is as close to the coils as I could get it and keep it secured to the board.

Will there be any indications other than internal fridge temp to know what you suggest is occurring?

[Scubawise]

we keep a thermometer hanging in the fridge amazon has them

[Scubawise]

here it is

[Scubawise]

this little device has saved our ASX many times.

[The_Breeze]

Originally Posted by Scubawise

this little device has saved our ASX many times.

Thanks. Have one and fridge holding steady at 40. 94 outside, cavity temp 98 as of 5PM. I think this is going to work well.

[Pete'sMH]

We purchased this (at about 2/3 the current cost!) and it works great. Can tell the fridge and freezer temp without opening the door. If you have an absorption fridge it is a worthwhile gadget.

[The_Breeze]

Originally Posted by Pete'sMH

We purchased this (at about 2/3 the current cost!) and it works great. Can tell the fridge and freezer temp without opening the door. If you have an absorption fridge it is a worthwhile gadget.

Sorry Bud. There's no 'this'. I think you meant to include an attachment? Thanks though.

[Pete'sMH]

Originally Posted by The_Breeze

Ok, I'll keep an eye on it. It tends to run all day during the day. It's 4PM, 96 in the shade, and the thermometer sensor sees 115 just on the other side of that board. That's up from 106 about 2 hours ago but it's stinking hot out there. The sensor is as close to the coils as I could get it and keep it secured to the board.

Will there be any indications other than internal fridge temp to know what you suggest is occurring?

If it was mine I’d take the power from the fridge control board so that your fans will run whenever the cooling system is running. But lacking that you could maybe put your temp sensor on or near the bottom of the cooling tubes so the fans will run if the temp of the coolant is higher than it should be as it returns to the boiler. I use the ARP fridge defender/controller with inside and outside fans and have my outside fan positioned so that it won’t restrict airflow but will still assist. It doesn’t take much help to assure good airflow as the cooling unit generates a good bit of heat and the hotter air already will be trying to rise. Notwithstanding, you’re probably fine with what you’ve got. It’s not rocket science.

[The_Breeze]

Originally Posted by Pete'sMH

If it was mine I’d take the power from the fridge control board so that your fans will run whenever the cooling system is running. But lacking that you could maybe put your temp sensor on or near the bottom of the cooling tubes so the fans will run if the temp of the coolant is higher than it should be as it returns to the boiler. I use the ARP fridge defender/controller with inside and outside fans and have my outside fan positioned so that it won’t restrict airflow but will still assist. It doesn’t take much help to assure good airflow as the cooling unit generates a good bit of heat and the hotter air already will be trying to rise. Notwithstanding, you’re probably fine with what you’ve got. It’s not rocket science.

I think we're on the same page. I wanted to 'assist' the natural updraft with the fans. I needed a constant 12v source to operate the thermostat and tapped into the control board power source.

I do notice the temp rises with the vent cover installed vs. removed. I did that to experiment with ventilation. It was 89 outside and the cavity temp rose to 115 with the cover installed. I also believe the fridge was running to cool the interior.

The temp sensor is in between the two fans and at the immediate edge of the board, right next to that coolant pipe.

I'll keep an eye on it. It may very well prove to be a failed experiment and I'm not beyond admitting that.

[Scubawise]

The Breeze proud of your work!

[Pete'sMH]

Originally Posted by the_breeze

sorry bud. There's no 'this'. I think you meant to include an attachment? Thanks though.

[attach]30799

[The_Breeze]

Originally Posted by Pete'sMH

[attach]30799

Thank you.