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.
1. Disconnect electrical power to pump.
2. Disconnect air supply and vent all air lines to
release pressure or vacuum.
3. Remove shroud, cylinder head and valve
components.
4. Remove cylinder and rings.
5. Clean all parts with water or non-petroleum based
solvent such as Gast AH255B Solvent. Do Not use
kerosene or ANY other combustible solvents.
6. Install piston seals, piston rings and rider rings on
piston. Locate ring joints approximately opposite
each other.
7. Use cylinder screws with washers to attach cylinder
to bracket. Tighten screws only until they are finger
tight.
8. Move pistons to top dead center position. Adjust
each cylinder flush with top of piston.
9. Torque cylinder screws to 150-160 in. lbs.
10. Replace valve components in original order.
11. Install cylinder head and head screws. The exhaust
ports have been marked on the cylinder heads by
omitting the ends of two of the fins. Do not
tighten screws at this time.
12 Install manifold nuts and seals on manifold. Insert
into cylinder head and manifold.
13. Torque head screws to 150-160 in. lbs.
14. Turn fan by hand to check that rod assembly is not
hitting head. If rod hits head, loosen cylinders and
adjust.
15. Install manifold and tighten manifold nut one-quarter
to one-half turn beyond finger tight.
16. Operate unit for 10 minutes. Tighten screws again.
17. Install fan shroud.
Gast will NOT guarantee field-rebuilt product
performance. For performance guarantee, the
product must be returned to a Gast Authorized
Service Facility.
Service Kit contents vary. Most contain head and
cylinder gaskets, valves, piston rings and seals, rider
rings and felt filters.
SERVICE KIT INSTALLATION
c
Disconnect electrical power supply cord before
installing Service Kit.
If product is hard wired into system, disconnect
electrical power at the circuit breaker or fuse box
before installing Service Kit.
Vent all air lines to release pressure or vacuum.
Failure to follow these instructions can result in
death, fire or electrical shock.
WARNING
Electrical Shock Hazard
Unit stalls after vacuum or pressure starts building
up in receiver:
1. Disconnect electrical power supply from unit.
2. Check that voltage from power source matches that
listed on nameplate.
3. Check wiring connections against diagram on
nameplate. Single voltage motors will operate only
at designated voltage.
Motor will not start:
1. Disconnect electrical power supply from unit.
2. Check that voltage from power source matches that
listed on nameplate.
3. Check wiring connections against diagram on
nameplate. Single voltage motors will operate only
at designated voltage.
4. Reconnect electrical supply to unit. Check that
power is on. If extension cord is used, check that it
is the correct size and length to adequately supply
power to the unit.
5. If unit will still not operate, contact your Gast
Distributor/Representative or a Gast Authorized
Service Facility.
Motor starts at 0 PSI but will not start under
pressure:
1. Replace the check valve.
2. Wait for the thermal overload switch to reset before
attempting to operate.
3. If unit will not restart, the thermal overload switch
may need to be replaced. If there isn’t a thermal
overload switch, the motor may be damaged and
requires service.
Motor starts intermittently:
1. Disconnect electrical power supply from unit.
2. Check points in the pressure or vacuum switch for
wear or dirt.
3. Check for dirt buildup or uneven wear.
4. Replace parts as required.
Unit cycles On-Off more often than when first
installed:
1. Check air receiver and drain water that has
accumulated.
Unit or motor is running more often than when first
installed:
1. Check system for air leaks. If new or different
pneumatic equipment has been added, the air
requirements may have changed.
2. Check and clean filters.
3. Check for buildup of foreign material on head.
4. Check valves and rings for wear and damage.
SPECIFIC PROBLEMS AND REMEDIES
