Husky H1506F stopped building pressure past ~15 psi, narrowed down to check or unloader valve

by John
(Wylie, TX, USA)

I’ve read through the majority of posts, so I’m sorry if I duplicate a question/answer here, but I need your help.

I have a Husky H1506F “pancake” compressor.

Husky H1506 air compressor

Husky H1506 air compressor

During regular use the motor made an odd change in noise, just for a second, sounded like something gave way, but then continued to run normally, except no more pressure built up. I think I’ve narrowed the problem down to either the check valve or unloader valve. So here is what my observations are:

1) Compressor runs air into the tank (not more than about 15 psi), and it holds for several hours once I turn the compressor off.

2) When the compressor is running there is continuous puffing air that comes out of the unloader line with the unloader valve removed. When the compressor is off there is no air escaping from the unloader line.

3) When the unloader valve is attached to the unloader line, the puffing air continues to escape through the valve release hole while the compressor is running.

4) How do you tell a defective unloader valve? I have a “condor” style straight unloader valve, and the actuator pin is depressed/not sticking out at rest (holding it in my hand). I’ve seen pictures of new unloader valves online and they show the pin sticking out, could I have a faulty unloader valve?

5) Although my tank will hold low psi air, it is possible I have a faulty check valve that is allowing higher pressure air to escape, but keeping in a lower psi?


Hey John. Thanks for taking the time to actually read some of the info on the site. Many folks just ask, and don’t realize that there are pages here with the answers already posted to their compressor problem questions.

If your unloader valve is dumping air all the time after the compressor stops, then that points to a leaky check valve.

When the compressor is running, is air being pulled into the air compressor via the intake port? You may have to remove the intake filter to check.

If air is being pulled in, pull the line from the pump to the tank (after dumping air). When the compressor is running, can you stop air from flowing out of the port to the tank by putting a piece of cardboard or plastic (not your bare hand) over it?

I’m thinking that you may have a valve or gasket failure based on what you have posted.

An update as a comment here would be appreciated.




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