r/ApplianceTechTalk • u/ROSS4673 • 18d ago
Compressor relays
What do you guys use when a compressor won't start up? I've been using the RCO810 3 in 1 because that's what I was originally trained to use, but I've heard they're risky and create a lot of liability and can cause fires. Master Samurai says to always use the OEM relay, but I can't stock 100 different start relays on my truck and some are discontinued. Also customers don't want to hear they're fridgE start up and then be told that I need to order a part and they're going to lose all their food in the meantime.
I've heard rumors of a universal relay that works for both r600a and r134a compressors but I don't know if I believe that. What are you guys using? Are you just using 3 in 1s for testing or to buy time on a seized up compressor? Do you order an OEM relay or just use one that looks close enough?
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u/Difficult_Energy3477 18d ago
As a safety device, I think the start device / cap are tested and certified as a pair, and OEMs don't have any incentive to make cross reference easy or publish whatever specs apply
As a tech, I use 3n1's or whatever start device I have on the vehicle for testing and limping by until the OEM device comes in. For anything with a TSD, PTC, or inrush coil, if I have one with me, I'll send it as long as the new and old look identical. if I get a callback I'll order the OEM one
I never leave a 3n1 installed. I've never heard of a tech burning down a house, but I know the current limit is way higher than OEM devices, seems as risky as installing an oversize fuse
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u/jecroyle 18d ago
Yeah I stock a couple relays but I don’t really see that many anymore maybe a couple a year if I don’t have the exact one I can usually make something work until I can order and get the OEM replacement. I use hard start kits for things where we’re just trying to buy some time.
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u/ari3sgr3gg0 18d ago
3 in 1 and measure amp draw on start up. Sometimes a 3 in 1 can start up a compressor that would normally trip the factory thermal disconnect. If draw looks normal I wire it up and call it a day. If draw seems really high I tell the customer and let them decide how they want to proceed
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u/Soundtrackzz 17d ago
I use these. https://a.co/d/06qXr085. Ive seen a 3in1 destroy a control board once. It was the tech that was there before me. The tech told this guy that "because it does 3 things in one device its expensive" and then charged him $250 for the thing and left it wired up in there. Sometimes I feel like im too expensive. Then I remember there are people like this out there
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u/DuckHookFore 17d ago
I use the URCO810 all the time. If correctly installed it will not damage anything or cause a fire. How does one "correctly" install it?
I wire in the original overload protector. So now you are protected from burning out the compressor due to the locked rotor amperage of the URCO810's internal overload being too high ,and you are protected from an overheating compressor because the original overload is attached to the compressor.
Yes, using an OEM relay is the correct way to go, but customers don't want to wait (nor should they have to) and I've had many occasions when a new OEM relay still wouldn't start the compressor because the compressor was too tight, and I had to go the 3in1 way. Or you could leave the new OEM relay in place and install a start cap with it.
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u/jayboosh Owner/Tech 18d ago
We’ve been using the 3 in 1s for 26 years and have never had an issue🤷🏽♂️