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kas-fearless
09-08-2015, 05:56 PM
Purchased a used chest freezer today and want to check if the thermostat is working correctly.

Do i point my black and white wire on each of the points and do a resistance check?

What sort of reading am i looking for at room temperature and at freezing?

By turning the knob should the reading change and to what?

Thank you

Brian_UK
09-08-2015, 07:14 PM
Depends on the type of thermostat, if it's an on/off switch then the circuit is make or break.

install monkey
09-08-2015, 08:14 PM
switch it on its highest setting and stick a thermometer in it- or after a few days look for a thin layer of frost around the inside walls- not the bottom though

kas-fearless
10-08-2015, 02:11 PM
Depends on the type of thermostat, if it's an on/off switch then the circuit is make or break.

Its the type with the capillary tube, i have read online that you can test it with a multi meter but not sure how exactly or what readings im looking for??

Anyone know?

The Viking
10-08-2015, 02:24 PM
Capillary tube or not, it can still function in different ways.
If it is a switching thermostat (ON/OFF) then between the two terminals used for running signals to the compressor you will have a short circuit (0Ω) whilst the probe is warmer than set-point and when the probe is colder than set-point you will find it to be open circuit (>999Ω).

The big question remains...
Why do you think the thermostat is faulty?

:cool:

kas-fearless
10-08-2015, 02:28 PM
Capillary tube or not, it can still function in different ways.
If it is a switching thermostat (ON/OFF) then between the two terminals used for running signals to the compressor you will have a short circuit (0Ω) whilst the probe is warmer than set-point and when the probe is colder than set-point you will find it to be open circuit (>999Ω).

The big question remains...
Why do you think the thermostat is faulty?

:cool:


Ok thats sums it up. Will give it a test

And the answer to the big question is that the chest freezer is constantly running

The Viking
10-08-2015, 02:44 PM
OK,
With it constantly running, what is the temperature inside it?

(Normally capillary type thermostats fails because they loose the gas charge inside them and therefore thinks it is too cold and stop the compressor from running)

:cool:

kas-fearless
10-08-2015, 03:04 PM
OK,
With it constantly running, what is the temperature inside it?

(Normally capillary type thermostats fails because they loose the gas charge inside them and therefore thinks it is too cold and stop the compressor from running)

:cool:

Not sure about what temperature it is, dont have a thermometer but it is quite cold and frosting up. The freezer does not have a heater to melt the ice so have to manually do it quite often. Which is the reason for wanting to test the thermostat and probably change it

The Viking
10-08-2015, 04:01 PM
Please don't take this as a recommendation, I only searched Google...

The quickest way for you to see what is happening or indeed if anything it wrong with the thermostat:
Thermometer (http://www.nextdaycatering.co.uk/p-32241-hygiplas-multistem-thermometer.aspx?gclid=Cj0KEQjwl6GuBRD8x4G646HX7ZYBEiQADGnzupf2YeGzao-BGd1lYsEJLndRct0eKwyLLngKL-OB1yAaAnS38P8HAQ)

:cool:

Glenn Moore
10-08-2015, 10:23 PM
Hi kas
Some manufacturers thermostats go open circuit ( Compressor stopped) some go short circuit (Compressor runs constant) this helps to preserve the food stuffs when the stat fails.
You can get a cheap fridge freezer thermometer in your local supermarket for a couple of quid.
Most Freezer stats have 3 terminals 2 for the stop/start of the compressor and the third for fault light . Some have a passive signal some have an active signal, ie
Make sure the thermostat capillary tube is entered into the sensor tube a far as possible , as its the end 100mm of the capillary tube that's is the sensing point

install monkey
11-08-2015, 08:50 PM
have you got the fast freeze initited( bypasses stat and runs constant)- usually an orange light will be lit if so