any fridge mechanics - help needed

Hoping somebody may be able to help .
I have been given an 80ltr 12 volt fridge / freezer that isn't working as it should and was hoping someone may be able to offer advice as may be the problem . Don't know the history of the unit as it was left at a friends house years ago and they were going to throw it out.
It is an older model called Icelander that only has a 12volt input not mains power . It uses a Domus T26K dc 12/24v R134a compressor .
Everything seems to be working in that I can set a temperature and the fridge compressor kicks in and starts to work . Takes a while to start to get cool inside but never gets down to desired temp . If I set it for -19deg it may get down to +4 or 5 deg after its left running overnight . Lowest i got it too was -2deg after setting it to -19 and running it for 12hours . Have tried everything I know to find the problem but I'm stumped .
Now thinking it needs regassing but not sure why gas would be missing and if so would it not get cold at all ?
Tried calling a few fridge repair places and as soon as I say its a 12 volt fridge they don't want to know about it even when I say all components are easy to get to like a normal chest freezer. I don't want to spend a lot of money on it but if the fault can be diagnosed/fixed it would be great. Any help would be greatly appreciated .
Cheers Paul


Posts: 5738

Date Joined: 18/01/12

 There could be a few things

Sun, 2017-05-21 11:22

 There could be a few things causing it but without gauges hooked up theres not a lot you can check except that the condensor fins are clear and have airflow thru them.

If ok there have a listen to the compressor when it is down to as cold as it'll go, may need to listen a while

If the compressor cuts in and out at all then it could be as simple as a faulty thermostat (if it has one) or low on gas so it cuts out on low suction pressure rather than set temp.
If the compressor keeps running continuously but doesnt cut out at all and doesnt get to set temp then it could be the compressor is worn out and so not pulling a low enough suction pressure.

Could also check that it is actually getting over 12 volts at the compressor, if it isnt for some reason then the compressor wont run at full speed and wont pull a low enough suction pressure.

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Date Joined: 09/11/06

Thanks Rob

Sun, 2017-05-21 11:41

Thanks Rob for the time to reply .
Condenser fins are clear and has a fan over them that works.
It has a thermostat and it works - if I change temp setting to what fridge is showing then it cuts out , if I then lower the setting fridge starts up again .
Do you know how I can check to see if I get 12v at the compressor? power goes into a box and then feeds out to fan/compressor etc . compressor has a 3 wire connector on it like any other compressor . Are these wires + and - plus something else ?

Posts: 5738

Date Joined: 18/01/12

Sorry about the delay, if

Sun, 2017-05-21 19:32

Sorry about the delay, if there is no 240 volt system in there, then use a multimeter and check whereever you can get at the wires, sometimes you can get the probe into the back of the plugs

Sounds like the thermo is working.

Im not familiar with those fridges but is it an evaporator plate type?
When it is running and cold feel if the plate/evaporator is significantly colder at the top than the bottom, especially if frosting only at the top

This is generally a sign its short of gas

____________________________________________________________________________

 Give a man a mask, and he'll show you his true face...

 

 

The older you get the more you realize that no one has a f++king clue what they're doing.

Everyone's just winging it.

 

t bone's picture

Posts: 351

Date Joined: 20/04/14

LPS

Mon, 2017-05-22 07:11

 As Rob mentioned, being a 12vdc only system makes it a bit easier to chase thigns with a multimeter.

If you have access to, or mates have got a little clamp meter (with the DC current function), it might also pay to check the current draw and see how it lines up to the nameplate or specs of compressor. Would be another option to determine if freon levels are low without putting a set of gauges on. A lot of those little systems are sealed, so ya need to install piercing line clamps or something just to get the gauges on. And after a while they alwways end up leaking anyhow. 

 

The 3 wires to the comp would most likey be (as you assumed) the "+" and "-" then the 3rd being a grounding bond to the chassis of compressor.