Refrigeration compressors using single phase electricity, need start kits.
The low torque motors will not start under a load. They must have additional help.
When I first started repairing commercial refrigeration compressors, all of the grocery stores used Copeland compressors.
The condensing units had built in boxes bolted to the unit. Each box held a potential relay, a start capacitor and a run capacitor.
Follow along as I go on a typical service call.
Approaching a condensing unit I first notice the condenser fan motor running normally. But the cool air blowing off of the condenser tells me the compressor is not running.
Turning off the power, I grab my amp meter.
Now I'm ready!!!
With the meter clipped around one of the two compressor wires, I turn on the breaker. The reading immediately jumps to the lock rotor amperage (LRA) displayed on the data plate.
Two possibilities cross my mind. Either the compressor has internal damage or the start and run components are not working properly.
Not wanting to begin tearing into the compressor I start at the component box.
What do I look for???
Are there any burnt wires? How about fluid coating the capacitors? Is the run capacitor swollen? Does the start capacitor have its top damaged?
Always look for the obvious!!! Sometimes a single loose wire is all it takes. If I see a problem, I replace the part and try it again.
What if all looks normal??? It means nothing!!! One, two, or all three could still be defective and not show a thing. So how do I know for sure?
This is suppose to be the part where I tell you I reach for my capacitor tester. The problem is, I don't own one and never have!!!
My time and my customer's perishable product, are too important. I simply replace all three parts. Now I know!!! If the compressor still doesn't start, time to begin pulling the head. Something is likely seized or busted inside.
What's that you say? What if I'm out in the middle of no where without the exact run capacitor, start capacitor, or potential relay?
Carry a start kit for emergencies!!! By start kit, I mean a one piece potential relay-start capacitor. It easily plugs onto the run capacitor and fits different motor sizes.
Don't leave the start kit permanently installed! Always use the recommended factory replacements.
Run capacitors can be mixed and matched by paralleling two or more. Remember, a 10mf and 15mf in parallel equals a 25mf.
Do I hear one more question? What if I'm throwing away perfectly good parts??
Over the years I have had few call backs replacing all three. I've found that trying to salvage one or more parts, is not worth the effort.
Call backs hurt your reputation and the customer's product.
Don't sweat the little things, just get those refrigeration compressors
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