Frigidaire refrigerator not cooling enough (Condenser coil is cold!)

Hi @jayeff, Thanks for the quick reply with many details!

The tenant said "it stops occasionally". So that could be temp control thermostat problem.

I haven't open anything in the freezer yet. But I did hear the evaporator fan running, and my finger could feel the cold air blowing. It can also bring temp down to around 32F degree (from a thermometer put in the freezer). I think the evaporator fan was still running when I opened the freezer and put my finger close to the vent.

I will try open up and check evaporator coil's feeling next.

I still don't understand why that condenser stay cool when compressor was running and hot (good to touch by hand for a long time). I compared to my home fridge (good) and the good compressor feels hotter (may touch by hand but not for a long time) than the bad one.

Thank you!

@coolerst

Check if the freezer light and refrigerator light turn off when you manually operate each of the door switches withthe door open.

Usually the evap fan turns off when a door is opened as you don't want to blow any cold air out.

The way it does this is usually through the door switch i.e. door open light on fan off, door closed , light off fan on. This is of course as long as the compressor is running as well.

The condenser coils should feel warm as this is where the heat from the compartments, which is absorbed by the refrigerant in the evaporator unit, is released to the outside air, before the refrigerant then passes through the expansion valve which changes it to a gas again and it passes through the evaporator i.e. now refrigerant is literally freezing cold.

If the evaporator is not freezing cold - be careful not to get your fingers literally stuck to it - then there is a problem with the sealed system, compressor, evap unit, condenser, piping or refrigerant. The only way to know is to find out the pressures.

Sometimes a leak may be indicated if there is an oily residue on the condenser or the compressor. There is a special oil mixed in with the refrigerant to lubricate the compressor and if there is a leak then the refrigerant will escape undetected but the oil may leave a trace, but not always and not if the leak is where you can't see it.

Hi @jayeff ,

There is no freezer light. The refrigerator light does turn off when I manually push down the door switch.

I opened the back panel board in the freezer: the evaporator coil has a little ice and quite some frost (feels like snow). I can't really tell if the temperature on the evaporator coil is freezing cold or not (should be below 32F degree but not sure if may reach 20F or lower). The evaporator fan runs fine.

The ground/back does not show any leak of refrigerant.

Hi @jayeff

I tried to rule out temp control thermostat problem by bypassing it, directly shorting the 2 pins connected to temp control thermostat's output (just to see whether temperature may drop to low enough if running compressor for long enough time). But after the short, the compressor still stopped after ~40 min. Then waited another 10 min it did not restart again. I plugged out power cable and plugged in did not start compressor either. I checked the short of the 2 pins connected to temp control thermostat's output and they were fine. I removed the short and connected the 2 pins back to connected to temp control thermostat's output -> the compressor still did not run -> I thought I must have broken something, but then after 1 couple minutes, the compressor ran again!

So what's the proper way to force compressor always running? Looks like shorting temp control thermostat's 2 output pins is not enough. Does the small timer box (close to the temp control thermostat) need to be hacked as well? Thanks

Hi @coolerst

OK.

The temp control thermostat goes via the defrost timer, part #23 -shelves diagram.

This timer controls the duration of the defrost cycle. The defrost cycle usually occurs once every 8-10 hours and lasts for about 20-25 minutes.

During this time the compressor is turned off and the defrost heater under the evap unit is turned on to help melt the accumulated ice from the evap unit.

The evap unit is protected from being damaged by a bi-metal thermostat which operates at about 50°F (it is close to the heater and measures its temp rather than the ambient in the compartment) to cut off the heater. Once the defrost timer ends its time for the defrost cycle the compressor is restarted to drive the temps back down again. When the temp in the freezer reaches about 25°F the bi-metal thermostat releases, enabling the heater circuit to be ready for the next defrost cycle 8- 10 hours later.

The point of all this is to tell you how it works and that the problem may be a faulty contact in the defrost timer.

If you check the "wiring diagram" i linked in my answer, the Refrigerator Compartment section applicable to your model (as there are two shown - lower left side of diagram) is the one on the right of the two with the timer and not the one on the left with the ADC board.

This may help to show you how the temperature thermostat connects through the timer to get to the compressor, so it is either the thermostat that turns off the compressor when the set temp is reached and turns it on again when the temperature has to be colder due to doors being opened and cold lost etc OR the defrost timer turns it off to commence the defrost cycle and turns it on again at the end of the timed defrost cycle. It is no use running the compressor trying to cool things down when you are trying to defrost.

With most auto defrost refrigerators you will notice that the freezer temp is about 0°F when set temp is reached and during the defrost cycle it will go up to about 32°F to help melt the ice with the heater and then when the defrost cycle is over it goes back down to 0°F again. Usually it never gets above this as you don't want to start defrosting the food.