1Z721 Takes forever to build pressure

by Rad W.
(Massachusetts, Norfolk)

Speedaire 1Z721 compressor

Speedaire 1Z721 compressor

Hello


I have a 1981 Speedaire 1Z721- 60gal., 2 stage, 240v, 5hp with pump# 3Z180.

This year it started taking longer to build 100+ lbs to run air tools.

Now it only goes up to around 80-90lbs after 30= minutes or so.

Not sure if this is something worth fixing or if I should just replace the compressor pump.

Oil is OK, the air intake port with filter cover removed seems to suck in good. No air leaks or oil coming out anywhere that I can see so not sure if something is blown internal that can be fixed easily or if a big tear down would be required.

Can you advise where I should start on debugging this please and if parts are still available for this model?

Thank you very much.

Rad

Comments for 1Z721 Takes forever to build pressure

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Jun 11, 2016
filter
by: Doug in s.d.ca

Rad:

No doubt. maybe something like a lawnmower type thing, or paper.

You can probably retrofit the newer type if you want.

Jun 10, 2016
Air Filter Question
by: Rad

My compressor is obviously older 1981 with a plastic round baffle for an air cleaner. Did this unit have disc filters inside this baffle to clean the intake air? Nothing is in the plastic baffle now which opens up like it should have had inserts of some sort. I see pictures with a different air breather set up on newer replacements.

Jun 09, 2016
R15B pump
by: Doug in s.d.ca

There's some extraneous stuff, but your answer may be here from the manual:

EVERY 90 DAYS OR 500 HOURS MAINTENANCE
1.
Change crankcase oil. Use type and grade oil as specified in the section on "Compressor Oil
Specifications".
2.
Check entire system for air leakage around fitti
ngs, connections, and gaskets, using soap solution and
brush.
3.
Tighten nuts and capscrews as required.
4.
Check and clean compressor valves, replace springs, discs and seats when worn or damaged.
CAUTION
Valves must be reinstalled in original position. Valve gaskets should be replaced each time valves are
serviced.
5.
Pull ring on all pressure relief valves to assure proper operation.
GENERAL MAINTENANCE NOTES
PRESSURE RELIEF VALVE:
The pressure relief valve is an automatic pop valve. Each valve is properly
adjusted for the maximum pressure permitted by tank
specifications and working pressure of the unit on
which it is installed. If it should pop, it will be necessary to drain all the air out of the tank in order to reseat
properly. Do not readjust.
TANK DRAIN VALVE:
Drain valve is located at bottom of tank. Open drain valve daily to drain condensation.
Do not open drain valve if tank pr
essure exceeds 25 PSIG. The automatic tank drain equipped compressor
requires draining manually once a week.
PRESSURE SWITCH:
The pressure switch is automatic and will start compressor at low pressure and stop
when the maximum pressure is reached. It is adjust
ed to start and stop compressor at the proper pressure
for the unit on which it is installed. Do not readjust.
BELTS:
Drive belts must be kept tight enough to prevent
slipping. If belts slip or squeak, see V-belt
maintenance in preceding section.
CAUTION
If belts are too tight, overload will be put on motor and motor bearings.
COMPRESSOR VALVES:
If compressor fails to pump air or seems slow in filling up tank, disconnect unit from
power source and remove valves and clean thoroughly,
using compressed air and a soft wire brush. After
cleaning exceptional care must be taken that all parts
are replaced in exactly the same position and all
joints must be tight or the compressor will not function properly. When all valves are replaced and
connections tight, close hand valve at tank outlet for final test. Valve gaskets should be replaced each time
valves are removed from pump.
15
GENERAL MAINTENANCE (Cont'd.)
CENTRIFUGAL UNLOADER AND UNLOADER PRESSURE RELEASE VALVE:
The centrifugal unloader is operated by two governor weights. It is totally enclosed and lubricated from
the crankcase of the compressor. When compressor starts, the governor weights automatically open
compressing the main spring, allowing the unloader
pressure release valve to close. When the
compressor stops, the main spring returns the governor weights to normal position opening the
unloader pressure release valve and unloading the compressor. This prevents overloading the motor
when starting. If air continues to escape through the governor or unloader pressure release valve while
operating, this is an indication that the unloader pressure release valve is not closing tightly and may be
held open by foreign substance which has lodged on the seat. In order to correct this, remove the governor release valve cap, giving access to unloader pressure release valve spring and ball. Clean thoroughly and return parts in the same order in which they were removed. Loose drive belts can also
cause unloader to leak by preventing the compressor from reaching proper speed. (See "BELTS"
above).

Given it's a 1500 dollar pump, I'd check all this before giving up on it.

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