I have a small apartment fridge in my machine shop.
It is made in china and it was a garage sale buy, think I paid $30.
Magic Chef is the brand, but they are all made in china with a different
name slapped on them. It is 33" tall, I think they call it 4.4 cu ft size.
It will hold 24 beers/sodas, whatever. Serves my needs super well.
The other week I had a problem with it. So far it had been running
perfectly for 3 or 4 years. It was making a loud click and the compressor
was not coming on. The click was the thermal overload cutting out.
I went behind and felt the compressor, and it was super hot to the touch.
I figured the compressor was toast. So I remembered Lowes and HD sold
these small fridges, so I went online and looked at prices. HD had the regular
fair, and Lowes happened to be having a back to school or back to college sale.
They had my exact fridge, normal price $200 on sale for $120. Great I thought.
I was going to go out and buy it, but then I thought... Maybe I should check
the compressor one more time. I remembered that aside from the obvious
thermostat inside the fridge, they sometimes had a starting relay, as most
single phase motors need some way to activate the Start winding.
So on the back of the fridge is a wiring schematic, and there it was. Some
some component called a PTC Relay. I found it under a plastic cover, where
the wires plug on to the compressor. It was a plastic box, the size of an ice
cube. Kind of like an electrical plug that connects to the input pins of the
compressor, with something inside. It had a thin cover with a stainless steel
clip. I removed the cover and inside was some thin steel bent to form a
spring terminal affair. 2 of them actually, and in between the spring terminals
was a disc the size of a nickle. I wondered what it was. I grabbed my needle
nose pliers and pulled it out. It looked like sintered metal, and was silver or
some kind of solder coated on both sides. It was actually broken, with 1/3
or 1/4 of the edge broken off. I did not have high hopes of fixing it, but I
thought maybe polish it up and put it back together and see.....
The side where it looked like melted solder or silver plating, I took a file and
made it smooth again. I bent the spring terminals in the housing so they had
good tension on the disc, and I re-inserted the strange disc into the plastic
housing. I plugged it back on to the compressor. Then I tried the fridge.
I plugged it into the wall outlet, and it started up ! ! ! Great I thought.
I un-plugged it and waited a few seconds, and plugged it back in again,
and no luck, it just hummed like before. So I took the relay thingy apart
again, and the disc was super burning hot! Nothing I could do, so I put it
back together again and tried it. Well the fridge started up running again !
I left it to run, and just to see, I left it overnight.
The next day, the beer was cold and the compressor was fine. I felt it
with my hand, and it was only slightly warm. Great, I fixed it, but I was
leary about that disc with the broken off edge. I guess filing off the solder
and re-bending the spring terminal was the fix, but there was a part number
on the relay cover. It was P6R8MC. I looked it up on Google and they were
selling them on Amazon and Ebay. HuuH! I found a new one, same part
number, on Ebay for $5 and free shipping, from a USA seller. Great.
So I find out PTC relay means Positive Temperature Coefficient relay.
The disc is some mix of semiconducting elements, that pass current
when it is cold, and itself is resistive, so it heats up from the current, and
then as it gets hot, it conducts less, and severely limits and all but cuts off
the current flow. I am used to mechanical start relays, with a real coil
of magnet wire and contacts and such, that sense current magnetically.
I never seen a PTC device before.
But anyhow, my beer fridge works, and I have a new spare PTC start relay.
I will probably put the new one in, but so far it works. I am glad I diagnosed
the problem, instead of buying a new fridge and sending my old one to the
landfill. I hate this throw away consume consume consume society.
So happy I was not drawn in for the on-sale fridge at Lowes. For a little
thinking and diligence, my fridge is fixed. And a $5 part assures a permanent fix.
I hope my story helps some people here, should they ever experience a problem
with their fridge. If you called a repair man, it would likely cost $300 for them to
come out. And for a $200 fridge, no one would really do that.
-Doozer
