I was hoping that someone in this newsgroup might be able to help with this
problem. I recently inherited an old Sears 1hp air compressor from the
1970's -- (model 160.171140). It wasn't in great shape but since I don't
have one, I thought it would be great to fix up for the shop (this was back
when Sears/Craftsman made decent tools right?). Anyway, I ordered the
replacement parts from Sears at greatly inflated prices and they arrived
today. They are not identical to the ones that were originally on the
compressor, not that I expected them to. Most of the pieces worked out
ok--the check valve was identical, gaskets fit great, shut off and safety
valve is different but checks out (actually made of brass instead of the
original plastic!) but the pressure switch is giving me some trouble...
It is a Square D Pumptrol Pressure Switch (I have the model and specs if
that will help) and on the underside of the swich is attached a valve with
four threaded holes in it. The one on the bottom is where it attaches to the
shut off/safety valve, but I don't know about the other three? They are all
connected so the tank wont hold any air. Can I get some covers or plugs to
fill them all? On the old switch, there was a guage that showed the psi in
the tank but this new one does not. Should there be another valve or guage
threaded into the pressure switch? I'm a bit worried that if I simply plug
those holes, the motor won't know when to shut off? Is that how it works?
I would really appreciate any help you could give me on this problem. I
dread having to call sears for assistance since I don't really have half a
day to wait on the tele just to talk to someone who has no idea what they're
talking about so they can tell me that I need to schedule a service call!!
You can get plugs and even a gauge at Many hardware stores, Lowes,
Home Depot, Grainger, etc...
Bring the switch with you so you can select the proper parts, and
don't forget the teflon tape.
The switch should connect between the tank, the pump, a safety valve,
and the regulator. You have a regulator, right?
Yes, remarkably, the drain plug is absolutely fine. The problem was the
check valve leaking and the on/off turn valve did not close tightly. That
being said, I have already ordered the replacement parts (plus a few others
just to tidy things up). My question is concerning the shut off/safety valve
that has "too many holes".
I dont have that particular model but the manifold on mine has:
the pressure swtich on the top
the tank on the bottom
outlet hose in a lower hole on the side
tank shut off in a lower hole opposite the hose
pressure gauge in an upper hole
safety pressure-relief switch in the other upper hole opposite the
You'll have to look into the manifold and examine its internal
structure because it does make a difference where the parts are
screwed in. I sent it to Sears for repair once and they put
everything back together in the wrong spots. The pressure gauge read
the pressure in the hose, after the shut off valve, rather than the
pressure in the tank before the shutoff valve.
BTW, I found that the local ACE hardware store carries a complete line
of compressor parts.
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