Compressor won't turn on.

10 years 6 months ago #454 by jgliebe3
Compressor won't turn on. was created by jgliebe3
80gal Husky with Condor MDR21 controller will not turn on. I checked all voltages and manually defeated the pushbutton interlock for the controller cover to no effect. Suggestions?

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10 years 6 months ago #455 by MTR-Admin
Replied by MTR-Admin on topic Compressor won't turn on.
Thanks for the post!

How are the Pressure Switch contacts? If they're corroded this can obviously cause it to not start. Then again it could also be the manual switch itself which actuates the copper contacts in the switch.

Do you hear a humming noise, or any sound at all when you attempt to turn it on?

- MTR

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10 years 6 months ago #458 by jgliebe3
Replied by jgliebe3 on topic Compressor won't turn on.
No noises whatsoever. Contacts are good and the MDR21 has no OFF-Auto switch on it like some have. The only way to "Energize" it is by shutting the breaker or plugging it in. It should go on at about 140# or so, but does not go on even when bled all the way down, as it is now.

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10 years 6 months ago - 10 years 6 months ago #459 by MTR-Admin
Replied by MTR-Admin on topic Compressor won't turn on.
It sounds like the Pressure Switch just needs to be replaced. It seems the diaphragm underneath the contacts is either damaged, sticking or has debris or corrosion inside which won't allow it to sense pressure accurately.

Also, do you hear the small Unloader Valve on the bottom bleed off the excess air pressure after the unit shuts off? It should dump or unload the excess pump head pressure for a few second after shut off. The 1/4" plastic (or copper) tube runs from this to the tank Check Valve.

If it's not unloading it could be the Valve itself isn't "unloading" the head pressure so when it attempts to restart, it can't overcome the pressure.

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10 years 6 months ago #461 by jgliebe3
Replied by jgliebe3 on topic Compressor won't turn on.
I do not remember hearing that ever; however, it is a noisy area, so it might have been doing that. Seems to me a good bet that the control switch is the problem. I take it that the unloader is different than the relief valve on the side of the control switch.

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10 years 6 months ago #462 by MTR-Admin
Replied by MTR-Admin on topic Compressor won't turn on.
Correct, the Safety Relief Valve will only go off if the unit pressurizes above what the Pressure Switch is set for (typically 25 PSI or so above Max PSI).

This small unloader valve needs to dump the excess air out of the transfer line and off of the pump head in order for the unit to restart.

Good chance it's this Valve, but the Pressure Switch comes with the Valve installed so this may be a safer bet.

- MTR

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