Frequently Asked Questions About Domestic Refrigerator Repair:
Shorting the start relay out for testing?
I've just finished reading the articles on your web site and I must say that they were excellent. Very interesting and informative with clear easy to read diagrams. I will probably be ordering your book.
I am a retired civil engineer (PE) and my education took me through some mechanical and electrical theory That was a long time ago but some of it remained with me. I do like to service my own appliances when I can, and am currently having a problem with my Hotpoint bottom freezer refrigerator, model # 1CBA215F4, which began life in 1964. It's still in excellent cosmetic condition and we use it as a second back-up refrigerator in the basement of our house. There appears to be no fan in this unit. There is no air connection between the freezer and the fresh food compartment. They are physically isolated from each other...it looks like the freezer is cooled by a plate (non-removable, although there are 2 sheet metal screws in it's face) at the back of the freezer compartment.
The problem is that when it tries to cycle on, there is a kind of buzzing rattle from the relay plugged on to the compressor, which lasts about 5 seconds and then the protector (a small cylindrical device wired to the relay (called the "guardette assembly") opens, so that the compressor cannot turn on. If left alone, this procedure will keep on repeating every 20 seconds or so, and of course there is no cooling...both freezer and fresh food compartment remain at room temperature.
My guess is that the relay is probably defective and I would replace it, except for one thing: prior to this no-cooling situation another problem developed about 2 years ago which we just lived with because, as I mentioned, it is a secondary unit. This problem was that the freezer would not get cold enough to freeze food unless the cold control was set such that the fresh food compartment got so cold that food started to freeze there. So we just stopped using the freezer. Now I'm wondering if the problem with the unit is something other than just a bad relay.
Also, I realize that the relay/protector unit will open in order to prevent more serious damage to another component, but because of how it is buzzing (which to me indicates rapid making-breaking of contacts) I suspect the relay itself is defective. I wish I could be sure before starting to buy replacement parts. Should I possibly just put line current across the 2 terminals on the compressor that the relay plugs into to see if the compressor turns on?
No!
Is this dangerous to the compressor?
Yes, if the compressor fails to start the windings of the motor will smoke inside the hermetic system causing what we call an acid contaminated system.
Nice fridge by the way. I've done a few compressors in these because for many years you couldn't buy them anymore. I see recently GE has come out with a modern version of this same design.
So what your compressor is doing is cycling on it's overload. This can happen because of a problem with the compressor itself or it may be the relay and overload. As far as testing to see if either are defective and trace down the cause, I find ohm and amp meter readings inconclusive in many cases. What I usually do is install a Hard Start Pack (in your case an RCO-410), and see what happens. Being in the business if it doesn't work I would just resell it the next time but in your case you might have to take the bite on the price as electrical parts are rarely returnable. The device has a capacitor on it which lowers the start amperage and is made for a solution to start older compressors like yours.
Your other problem that you had a few years back is likely due to a very minute leak somewhere in the system so it likely will get worse over the years. On these designs refrigerant first cycles through the coils in the refrigerator section then through the freezer. So if any refrigerant is missing the freezer then won’t be cold enough.
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