Thanks for the post!

There are a couple of reasons this could be happening. First, do you have the model# of your compressor? This would help greatly.

If it's a direct-drive unit, first check to make sure the Belt isn't split, torn or has come off of the 'flywheel'. This is the simplest reason the motor would be running yet the pump would not be.

Also, make sure to spray soapy water on all fittings and hoses to confirm you have no major air leak.

It's tough to say if it's a Pressure Switch problem because I'm not sure what the preset PSI ratings are for the unit without a model#. It could be that the unit never reached the preset PSI for the Safety Valve to blow off; typically Safety Valves are preset to blow off at around 20 to 30 PSI above the max PSI of the unit (which the Pressure Switch is set to cut the unit off at).

If you can reply with either the model# or even a photo of the unit, I'm sure we'll be able to narrow this down!

- MTR

Well the H1504ST model compressor does have a Belt, it's a very small, cogged Belt and it's very common for this Belt to snap and come off of the Crank Flywheel.
I would certainly check the Belt as that's most likely the problem.

If you click on the link below you can view the parts diagram for this unit and even a video which shows the Belt in an installation.

www.mastertoolrepair.com/husky-parts-h15...lb22e2ic9lh4gma7mdl0

Hope this helps...

- MTR