Help my fridge keep it's cool!

[clyne]

So, earlier this year I managed to get my hands on a second hand full size fridge that I can squeeze 8 kegs into. Life was good, pipes run, nice cold beers on tap.

However, a couple of weeks ago the fridge just stopped working. It's in my garage. Fine, I thought, I've had this problem with my previous fridge (which was a fridge/freezer combo), I'll just adjust the light so it's on permanently, giving off enough heat to keep the thermostat from cutting out. Only problem is the light inside this fridge is dead as well!

I've tried blasting both the inside and the rear of the fridge with hot air and unplugging the fridge/re plugging it in - all to no avail. I've left a tube heater running behind the fridge for 24 hours again to no avail. The fuse in the plug is OK. I've removed the housing from a connection box on the rear bottom of the fridge and can see voltage coming in from the mains and going out to what I assume is the thermostat inside the fridge.

Help! Is it just the cold (seems to much of a coincidence to me)? And if so what can I do to get my baby running cool again.

I'm tempted to just leave it given the cold(ish) temperatures this time of year - but they can fluctuate quite a but as well, today was around 13C (although inside the garage probably never made it that high), and I keep yeast in my fridge too so would really rather it kept running.

It's an Indesit (can't find the model, although it may be written inside somewhere - I've just not taken the kegs out yet). The thermostat board is manufactured by Whirlpool (2572 is the model written on it).

 

[Tanglefoot]

Most modern fridges and their coolants are designed to work at ambient room temperature, you'd be better off with an older CFC filled model - or insulate your garage.
I have a couple of fridges in my shed with no problem over winter but it's packed with celotex in the walls, floor and ceiling.

 

[clyne]

I guess what I don’t understand is why the light would also cut out? And where is the star if I wanted to try and warm it up/insulate it? It’s about 10C here at the mo so not really cold yet fridge still refuses to play ball.

 

[MashBag]

"

I'll just adjust the light so it's on permanently, giving off enough heat to keep the thermostat from cutting out.

So it runs continuously?

I have to say I am confused.

And why are you heating the back?

Frudge stat probes are normally on the inside... Cos it's the insure temp they control.

Is there an inkbird involved?

 

[tigertim]

Most domestic fridges only have one thermostat and that's the one which monitors the temperature of the internal compartment so, as long as the temperature in the fridge is above 4C, I would expect the compressor to start regardless of the ambient temperature.

It may sound obvious, but is the thermostat turned on? Whilst I'm not sure of the specifics of your fridge, many fridges have the thermostat control in the internal compartment where you can set a dial between 0 and 6. These, confusingly, don't represent actual temperatures; more "amount of cooling" with 6 being "maximum cooling" (i.e. cooler) and 1 being "minimum cooling" (i.e. warmer). Crucially, if you turn it to 0, not only does it turn the fridge off but the internal light will also cease to function. It's possible this knob could have been inadvertently rotated to 0 when you put a keg in or out of the fridge.

If you have power to the fridge and neither the internal light nor compressor operate, I would suspect that thermostat switch if your fridge has one.

ETA : just Googled the part number from your OP and see it's some kind of electronic thermostat rather than a boggo manual one so my steps above probably aren't valid. However, that's still the component I'd suspect first and at least want to eliminate before looking elsewhere. I'm not sure how proficient you are with electrics/electronics, but I would imagine bypassing it to force the fridge to come on as a process of elimination should theoretically be simple enough. Domestic fridges are not complex appliances

 

[MashBag]

Domestic fridges are not complex appliances

Good call.

You could prolly see where I was going with the inkbird.

 

[clyne]

Thanks @MashBag and @tigertim - that’s given me lots to go on. I’m going to have a play over the weekend (may get some help from the son who knows more about electrics/electronics than me!) and see what I can do. Will keep you informed of progress

 

[MashBag]

Try by-passing the stat first and let's see what happens. It should get flippin cold.

If it doesn't it is gas or compresser. Let us know - there is more.

If it does get cold, leave it bypassed and get an inkbird on it.

 

[gavp1979]

My fermentation fridge packed in earlier this year, before scrapping it I tried bypassing the thermostat as suggested above and bingo, works perfectly again now and gets colder than it ever did before for cold crashing. I was already controlling the temp with an inkbird so didn't need to do anything else, in your case you could probably just pass the inkbird probe through the drain plug

 

[Twostage]

My fermentation fridge packed in earlier this year, before scrapping it I tried bypassing the thermostat as suggested above and bingo, works perfectly again now and gets colder than it ever did before for cold crashing. I was already controlling the temp with an inkbird so didn't need to do anything else, in your case you could probably just pass the inkbird probe through the drain plug

Now THAT I'm going to keep in mind. Hadn't thought about it that way, I'm using a computerised thermostat to control a mechanical one. The fridge I use has an ice box at the top and I've removed it's door so I can get it down to about -2 which is enough for what I do. But it's good to know there is a way to push it further if needed and a get out of jail free card if the stat fails.

 

[tigertim]

It's worth mentioning that it's not generally a good idea to push refrigeration devices below their design temperatures.

The basic principle is that the compressed, gaseous refrigerant from the compressor passes through the condenser on the back of the fridge and condenses into a liquid as it rejects heat. This liquid then passes through a fixed metering device (i.e. a small hole) into the evaporator where it goes from a high pressure liquid into a low pressure environment, immediately flashing into a gas, absorbing heat. This evaporation from liquid to gas is what causes the cooling effect in the fridge compartment. The gas then returns to the compressor to repeat the cycle.

However, if the refrigerant passing through the evaporator is unable to absorb enough heat from the internal compartment before returning to the compressor (because the compartment is below the system's design temperatures), a proportion of it will return to the compressor as liquid; this is known as "liquid slugging". This is a problem because liquid is not compressible in the same way as gas is - a bit like getting water into a car engine. The result would be eventual compressor failure.

So although the design principle of fridges and freezers are largely identical, there are significant (but largely invisible) differences with the surface area and volume of the condenser and evaporator, as well as the length of the capillary tube metering device - and in some cases, the refrigerant type.

In summary, don't push a fridge lower than freezing point and if you bypass the internal thermostat to be replaced with an Inkbird or other external temperature control, don't attach its sensor to a full keg or other large thermal load in the fridge - it may take many hours or even a day to get that keg down to temperature and, if the compressor is running that whole time, the evaporator will end up well below freezing for an extended period. Occasional ice formation on the inside of a fridge is normal, but it's certainly not something you want to be aiming for.

 

[MashBag]

Good point.

 

[dtashmore]

how I read the initial problem is that neither the compressor or light are getting power, if the lamp is ok then the power is being lost at source, the lamp is not controlled by the thermostat but usually from a door switch. I would start by following the electrical connections from the plug through to the door switch, looking for a broken connection. I am not familiar with that fridge but the only other possibility is that it is a control board fault.

 

[gavp1979]

Although uncommon I have seen 1 fridge where the light does not come on unless the fridge is cooling, that also had a digital thermostat similar to the ops

 

[clyne]

So, I've been away for a couple of days at the weekend but still no further on. I've taken all of the kegs out of the fridge to ensure that I hadn't knocked anything. In the process I found the probe for the thermostat, so I know where that is. However, it may be a moot point, because I think the way I'm going to have to go is to bypass this stat and use an inkbird as mentioned to control the temp.

The big question I have is - how! :-) How do I bypass the thermostat? I've got pics of the control board and the wiring at the back of the fridge, but a bit of advice on how to override it and have the compressor run (I can live without the fridge light) would be brilliant.

One thing I did try was checking the continuity of the cable that goes from the wiring harness at the rear of the fridge up to the controller. I was expecting continuity but didn't find it. I thought I'd found the problem so ran a new cable (which then did test continuously) but to no avail. Still no working fridge. I also can't see how this cable could have been damaged - from what I can tell it runs from the wiring harness up the side of the fridge (which is the side with no holes drilled in it) and straight to the control board. Could there be an inline relay that would interfere with continuity?

Either way - next step is for me to try and override the thermostat to determine if the compressor is still running and I can at least do SOMETHING with the fridge other than get rid and replace it.

As always help much appreciated

 

[Rodcx500z]

Hi Glyne, i am only guessing here, on my my fridge which is a modern one about 2-1/2 years old you turn the thermostat nob up to full and just plug the inkbird in, i got this info on here hope this helps

 

[tigertim]

nob

How rude!

It's an Indesit (can't find the model, although it may be written inside somewhere - I've just not taken the kegs out yet).

Now that you’ve taken the kegs out, can you see the plate with the details and model number on? Having the model number may help locate a wiring diagram which would give more helpful information in terms of troubleshooting.

 

[clyne]

Still can’t find a model number even inside the fridge - here’s a couple of pics if that helps?

I

 

[Rodcx500z]

Mine is an indesit tall larder fridge, the dial is turned to full and plugged into an inkbird works a treat

 

[Rodcx500z]

Here’s a couple of pics