Husky WL660900AJ will not turn on to maintain pressure.

by Benjamin
(Metropolitan DC)

Used WL660900AJ branded Husky. Will turn on and build to 90psi (and no more).

Once pressure drops considerably from use, pump will not turn on to fill the tank again. Manually switching the unit "on/off" does not effect this condition.

Have manually emptied tank (through tools and by use of release valve), opened drain plug. Closed drain plug and attempted to start unit again, unit will not turn back on.

Unit has power, verified at wall outlet and by jumping pump leads (pump will turn on this way).

Weather has since changed to bitterly cold. Unit has same conditions above but now has a significant leak once the unit has been switched to the "off" position.

Comments for Husky WL660900AJ will not turn on to maintain pressure.

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Nov 23, 2014
Won't restart
by: Bill

Benjamin, when the compressor stops at 90 PSI, is it because the pressure switch is tripping out?

It likely isn't the switch as you've indicated you've added a new one and the problem persists.

If it is not the pressure switch tripping out, then I would suspect that it's the motor thermal cutout reacting to heat in the motor, and that may indicate an issue with the run capacitor or the power supply over all.

If the pressure switch is not turning off the power at 90 PSI but the compressor still shuts down, then it were me, I'd be checking the capacitors. See the page how to do that on this site.


Nov 23, 2014
by: Benjamin

The compressor will not build to more than 90 psi, it shuts off at that point.

I replaced the pressure switch and check valve on the advise from a compressor shop. No difference has been observed. The unit still shuts off at 90 psi and will not restart if air pressure drops significantly from use/draining.

Nov 19, 2014
Husky WL660900AJ compressor
by: Bill

Benjamin, the question I have is why does it stop?

The Husky WL660900AJ has an upper pressure cut out at 150 or 155 PSI I believe so that's the pressure area where it should shut off on cut out.

You say it will build to 90 PSI and no more. Does that mean that the compressor stops at 90 PSI, or does it mean that it continues to run at 90 PSI but the pressure will go no higher?

If the compressor is shutting off at 90 PSI, that would suggest the pressure switch is the problem, but only if the pressure switch is tripping off. If it's the motor thermal cut out or the reset button shutting the compressor down at 90 PSI, then it's likely power related.

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