Freezer thermostat location

[BillKny]

We are in the middle of building a new super insulated freezer box.

When it is time to reinstall the evaporator, where is the best location for the temperature sensor for the digital thermostat? And why is your recommendation best?

Many of the mechanical thermostat sensors were mounted on the evaporator itself, or... it could be on a wall close to the evaporator... or as far from it as possible... or hanging in air somewhere in the middle. Up near the top? Down low? In the middle?

If it matters, the freezer will be used for freezing of fresh caught fish, and long term storage of miscellaneous cruising provisions and will be kept at about 0F. I have control over both the set point and the hysteresis of the controller, if that matters...

[sailjumanji]

I installed an Isotherm ITC Digital Thermostat kit on both the upright refrigerator, and the in-counter freezer. The freezer is rectangular-shaped box with an "L" shaped evaporator plate. I asked the service technician for Indel Webasto Marine, Italy, where to install the ITC thermostat. His answer:

"The manual of the ITC and SEC states quite clearly that the probe has to be installed opposite of the evaporator, just like you mentioned, and that the probe has to be installed 5 cm from the bottom (2 inches). See page 38 of the manual."

A follow-up question, I asked that I assume we will need to keep frozen food away from the thermostat grille? It probably needs to have clear access to air temp in the freezer compartment, and not be surrounded by frozen items? Or does it matter? His reply:

"The thermostat probe is designed to read the environmental temperature, so it will be better not to be covered by frozen items."

Here is where I installed it in the freezer. (I was doing some testing with frozen water bottles.) Works well. The ITC also has a metal sleeve covering the end of the thermostat wire, behind the plastic grill. How much of the thermostat wire end you expose/slide outside of that sleeve, will have a direct effect on sensitivity. Fully exposed, my freezer cycles on 3 deg F range. Enclosed fully, it cycles on 6 deg F range. (Because it is being shielded by the air temperature change in the box.)

Not sure why the one pic is posted sideways, but you can see ITC for fridge on top, and freezer on bottom. Probably best thing is visual confirmation that internal temp is ok, without having to open unit door! Oh, and our freezer can maintain temp at about 18-20 deg F, but that is about it. It doesn't have enough foam thickness to get colder in 85 deg F ambient temp, and it about to be swapped out for a box with 3 inches of foam.

[OzeLouie]

Originally Posted by BillKny

We are in the middle of building a new super insulated freezer box.

When it is time to reinstall the evaporator, where is the best location for the temperature sensor for the digital thermostat? And why is your recommendation best?

Many of the mechanical thermostat sensors were mounted on the evaporator itself, or... it could be on a wall close to the evaporator... or as far from it as possible... or hanging in air somewhere in the middle. Up near the top? Down low? In the middle?

If it matters, the freezer will be used for freezing of fresh caught fish, and long term storage of miscellaneous cruising provisions and will be kept at about 0F. I have control over both the set point and the hysteresis of the controller, if that matters...

Hi Bill,

Hopefully you are using a digital controller which can be remotely located with the sensor bulb flexible for locating in the freezer space.
Suggest leaving the temperature sensing bulb location flexible until the freezer is operative then look for the warmest location in the freezer cabinet. Controlling the freezer to required temperature from that point ensures that temperatures are always at the required minimum elsewhere throughout the cabinet.

Cheers Louie