I just purchased a switch to repair my old sears 1.5hp compressor.
The original problem I had was there was a leak in the diaphram as
well as once the topend shutoff was reached (at 150psi) it would leak
air rapidly. If I interrupted the power before it reached shutoff it
would only leak from the diaphram and not have the rapid leak. I
requested a new part from sears and installed it. This solved one
problem, the diaphram no longer leaks, but I have kept the problem
where once it reaches shutoff (at 150psi) it leaks until the motor
fires again. If I interrupt the power while it is leaking it will
eventually stop leaking around 135 psi. Do I have a 2nd bad switch?
Have I not connected things correctly?
A friend of mine gave me this air compressor for free. I know that
generally things are worth what you pay for them but that did not
deter me. I have a small hot-dog air compressor and this is a pretty
substantial move up in compressors. The switch is new from Square-D
although I purchased it for double its cost from sears (hindsight gets
me every time). I noticed that the power cord from the wall is not
grounded and that the new switch has a small screw for that ground.
In other reading I have learned that the rapid leak from the switch
after shutoff is expected. This leak releives pressure but should
stop immediately. Generally most of the operation of the switch is a
mystery to me, if anyone cares to explain how the switch operates at a
level not requiring electrical engineering training I would enjoy the
Thanks for your thoughts!
17 years ago