4
Replacing Diaphragm
1. Remove the two Phillips-head screws then the
retainer plate and diaphragm.
2. Install the new diaphragm, pattern side up for
compressors, pattern side down for vacuum
pumps,onto the connecting rod.
3. Replace the retainer plate and attach with two
screws. Torque the screws to 30 in. lbs. on DOA
and DAA units and to 12 in. lbs. on MOA and
MAA units.
Replacing Inlet and Outlet Valves
1. Remove the slotted machine screw that holds
each valve in place.
2. Clean the stainless steel valves with water.
Valves are interchangeable on DOA and DAA
units.
3. Replace the outlet valve or install a new valve so
that the retaining bar is near the machine screw
hole. The retainer bar holds the valve in place.
4. Replace the inlet valve or install a new valve so
that the notch marked on the valve is in the
lower right hand corner towards the inlet of the
air chamber.
4. Replace the head on the pump. Torque the socket
cap screws to 90-100 in. lbs. on the DOA and DAA
units and 30 in. lbs. on the MOA and MAA units.
Do Not replace the connecting rod or motor bearings.
Check that all external accessories such as relief valves
and gauges are attached to cover and are not damaged
before re-operating product.
If pump still does not produce proper vacuum or
pressure, send unit to a Gast Authorized Service Facility
for repair.
