(East Yorkshire UK)
I have a large OLD compressor 2.5hp on about 200ltr tank, has been great, but last problem was either the start OR run capacitor failed… can’t remember which but that was changed and all has been great.
OK for about a year of occasional light use but now the it runs fine for anything up to 4 or 5 mins then the thermal cut out pops.
it will restart again within a matter of seconds but trips again after about 1 min.
I have done the troubleshooting checks and tests and proved ok, the mains supply 20 amp feed, no leaks on dump valve, pressure switch ok, still trips with the compressor belt removed, will with repeated resets (possibly 3 reset) will get up to 140 in main tank.
There also appears to be no excessive heat anywhere on motor or coils.
Am I right in assuming it could simply be the thermal trip switch that is poorly??
If so is it the black button itself that is the switch. Can I test it off the comp?? What rating will I need?
Many thanks for any help. Mike (UK)
Motor n stuff
Did you recheck the caps?
The thermal cutout may also be measuring overcurrent, which could be caused by bad run cap…
If that’s not it, then can we get pix of the blue box, inside and out (label)?
Question about testing capacitors
Excuse my ignorance but can you tell me in layman’s terms how to test the capacitors?
Do they need to be tested/ checked in situ or will they test the same if removed from the compressor?
Also is there any way to test /measure the thermal switch? Thanks, Mike.
Testing caps is discussed on these pages.
It’s not real easy to find, so try this link:
Follow the directions carefully.
Pretty much any meter (V.O.M.) will do the job, if it has a resistance function.
Most everything is covered, you want to use the site map to actually find some of it.
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