Fridge repair

I never thought I came to this point, repairing my fridge.  I wanted to retire the fridge long ago, and now it's over 10+ years.  We called the repairman a long time ago for some simple problems that I don't remember or I never knew. 

Then last summer the fridge wasn't cool enough.  There is still a big opening gap when the door is closed.  It wasn't a problem with the gaskets or the mounting of the door.  I think it's the door that is warped.  I cleaned the dust and put in some weather seals at the door and the fridge seems to work.  I got two thermometer to monitor the temperature.  The fridge is within spec.  The freezer isn't but it's less than -10 so you can make ice and preserve frozen food and ice cream for a while. No big deal.

Then the fridge went completely dead.  I wanted a simple replacement but my wife wanted an expensive upgrade.  So I tried to repair it instead.

The most important component is the compressor, sealed with a motor in it.  If you don't stress it too much, it could last forever.  A new one cost less than $300 but you need a professional to reseal the system.

If the compressor doesn't run at all, while everything else works, it is more likely that the solid state start relay, that most new fridges uses instead of the good old wire wound versions.

If the compressor doesn't run but feels warm or hot, that's mean it may be alive.  If you hear clicks every minute or so, that means the overload protection is turned on, while the compressor tried to start repeatedly.

It turns out it's pretty easy to test which one is bad.  Unfortunately in my fridge, the components are plugged into the compressor at the side near to the fridge wall.  You cannot move the compressor to get to them because the copper tubes are rigid. 

This is what I do.  Imagine that the relay and overload protector is plugged into the compressor like an electric socket into a plug.  Indeed there are three terminals like an electrical plug from the compressor.  You can't see it but keep that in mind and you won't damage anything.

First prey off the cover.  You won't break anything, except maybe if the cover is plastic.  Old fridges have a large capacitor that could give you electrical shock.  New ones don't but I would use a metal tool or wire to short everything to ground first before touching anything.

Then you take off the three wires connected to the terminals.  Take a picture first if you will forget which one is connected to which terminal.  You need a piler or two to separate the terminals.

You unplug the overload device first, which has one terminal, like preying off a very tight electrical socket from the plug from the side.  You need force, but be careful to pull it straight out without damaging the legs by sidewards forces.  Then you pull out the relay, two terminals, in the same way.  Now you can see the three bare legs from the compressor.

The overload protector is OK if it's 0 ohm across it.  If not, it's probably toasted and smell of such.

The compressor is probably OK if any two of it's three terminals has about 0 ohm across them.  And any terminal is not shorted to the ground.  (Test the resistance between each terminal and the ground terminal somewhere on the compressor, or the copper tubes.)  If you have a digital meter, the terminals are like two resistor back to back.  The total resistance, in the order of a few ohms, should add up.
 
Contrary to many advice which looked identical, it's surprisingly easy to test the relay.  One guy suggested to put a light bulb in series with the relay.  When you apply power the bulb should flash on for a moment.  My bulb stays on so it must be bad.  Of course you have to understand what is in series and have the confidence to tackle live electricity, which in some countries will kill you.

To make sure that the compressor actually works, you can apply power to the compressor directly, and apply the start voltage using a switch.  I won't try that because the terminals are hard to get to.

Also on ebay the relay cost $11 and express shipping cost a few dollars more.  It cost a few more times in the shops if you can find it in stock.

The other things are easy, like the auto defrost timer.  You can access the timer in front of the fridge near the floor.  Just turn the dial and the timer will move on to defrost mode and then off, so you know if the timer is bad.