Sunday, January 9, 2011

Fridge repair: the case of heard what you want to hear

So I hope my fridge compressor isn't dead, thought it's retirement time overdue.

So I searched and found the usual cases that isn't the fault of the compressor.  The overload device is good and I hear the clicking sound, meaning it was protecting the compressor motor against large current.  The reason of overload is because the start relay (PTC) is faulty, turning on the start coil all the time, instead of changing over to the run coil only.

The PTC is an easy target for faults.  But I would think burning out, always disconnect is more common.  I can't imagine how it is always short.  The test make sense.  Put a light bulb in series and the bulb should flash momentarily.  That's how the start coil works and then shut off.  My bulb is always on so I hope I only need to replace the start relay.

Fortunately I find one online for some $10.  But I have to wait a few days for it to arrive, wasting time. I plugged it in and the same thing happened.

What I think you need a conventional bulb with high wattage to shut that thing off.  I happened to use a CF bulb.

Since I wasted a few days, I might just as well test thoroughly the compressor before I gave up the fridge.  All the resistance between terminals are of low ohm.  I only have an analogue meter since my student days so I hope they are several ohms and they add up in series.  The terminals are not shorted to the case.

To make sure I tried to start the compressor manually.  It's pretty easy if you can clamp onto the three terminals.  Unfortunately the terminals do not face the back, but face the sidewall with little space to get into.  Also the remaining space is partially blocked by copper tubes.  I have to buy a bank of insulated terminal blocks that cost me another $8.  Those that you can cut off into individual connectors and have screws to tighten wires.  I screw the connectors onto the terminals.  It's hard work because of the lack of access but it worked.  I also brought out the ground and power wires.  I also connect wires to bypass the overload device.

It wouldn't start.  With or without the start coil on, the overload device is always triggered into open circuit.  When I bypass the overload, large current caused sparks.

It's simple.  I should have believed my meter.  The terminals are shorted to each other - zero ohm.  Nobody mentioned that because when the compressor is dead, there's nothing to talk about.  So when ever power is delivered into the compressor for whatever reason, the current is large and the overload protection will be triggered.

The compressor itself cost about the same as a simpler fridge.  If you add in the labor cost, it will be the same as a new fridge with some tiny scratches on it.

Sunday, January 2, 2011

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.

Permeable paving update

My permeable pavement proved itself during the flood.  In my concrete paved area, tubes are laid underground to prevent flooding.  But drains can be blocked.  My permeable paved area dries quickly when the rain stops.

The drying paving technique doesn't work, using lime and sand dry mixture to fill the gaps.  They will never turn rock solid and starts to wear off slowly, better than soil though.

My next idea will be filling the gaps with pure wet lime first, and then sweep dry sand on top and squeeze into the gaps.  Filling the gaps with wet lime is quick, because without sand in it the tool will not be blocked easily.  Add dry sand on top is clean and easy.  Hopefully it works.

Unfortunately, my lime bag got penetrated during the flood.  They may or may not be working anymore.

Super flush and sparkle a great success

The little hardware used almost immediately earn it's worth.  The chlorine tablets for swimming pools are much cheaper, last for weeks each, and you can even find it in Albertsons's supermarkets.  The pungent chlorine odour for the first flush in the morning is gone.  The toilet bowl remains crystal clear.  When it's not so clear you know it's time to add tablets.

The dual flush conversion doesn't work.  Its because the toilet bowl (not the tank) do not fill up full every time.  Using siphon to continuously fill the toilet bowl isn't practical.  Too risky.

The dripper did get blocked after some weeks.  But it's very cheap.  Now I'm using those that can be opened up to unblock or to see what happened.

Critter home a success

The modified critter home is a great success, passing the winter flood, storm and cold with flying colors.

The insulation is great.  It's water proof.  And even water leaked from the tiny cracks in the roof, they are still held in place by tapes even when wet.  They don't get wet and still functions, and water didn't drip from the ceiling.

The flaps and magnetic closure were designed to keep warm from cold draft.  It also prevents rain storms that went horizontal.

Well before the severe weather, we put the home on a pile of paving slaps to raise the height.  We can use a big bucket under the litter opening to collect waste in one go.  The horizontal rotating/sliding door works well for it's simplicity.

The raised acrylic platform inside the home is good.  Dirt mostly fall down onto the floor level.  The acrylic platform is kept clean by newspaper on top, fresh every day.

The gap below the platform and above the floor is filled with compacted plastic bags from the supermarkets.  They are pretty warm.

Washing the home frequently is a bad idea.  Too much work and it takes time to dry.  Now the platform is mostly clean, if not you can  pile more newspaper on top for a day or two.  You can empty the dirt on the floor once a week.  The wet litter has to be emptied through the hole daily or every other day if the weather is bad.  Once a month or so I use the steam cleaner to clean the house thoroughly, without moving the whole thing.

The heater using broken soldering iron is good.  It's simple mounting near the top so the critter cannot play with it.  It's shielded with wood plates.  Now that I don't wash and move around the house the mounting and wiring is simple.  It will never overheat.  It may be too mild but a warm wall instead of a freezing wall makes a lot of difference.  You can always use a higher power soldering iron when not in use, taking the tip away.

Improvements: kids can do the upside down bottle, but will wet the place a bit.  Keep the wet area away from the dry area so it will not make a wet mess.  The gaps on the side of the platform could be sealed to control where the dirt collects.