SAFETY INSTRUCTIONS
IMPORTANT!
Observe direction of flow. The bypass must
under no circumstances be closed or fitted with any shut-
off device.
IMPORTANT!
Continuous bypass operation without
releasing the water can cause the liquid to heat up which in
turn could damage the unit and endanger persons.
Possible preventive measures:
1. Limit the bypass duration (maximum temperature
160 °F [70 °C]); the duration is to be calculated by the
operator and in conjunction with the operating conditions.
2. Use fittings (e.g. thermal relief valve on water inlet) to
avoid heat increase.
SERVICE AND ADJUSTMENT
Servicing and adjusting work is only to be carried out by a
skilled tradesman.
to renew the piston rod seals and sleeves
Relieve the spring pack by means of the hand wheel (6).
Screw out the four inner hexagon screws (3). Remove the
spring guide (2) along with the spring plates (12) and hand
wheel.
CAUTION:
The hexagon nuts (7) are not to be
shifted from the set position. These are the locking
nuts to retain the maximum adjusting pressure.
Note
the sequence of the spring plates (12) for reassembling.
Push out complete piston assembly (13-22A) over the bypass.
Hold piston (14) with size 10 wrench and remove hexagon
nut (16). Take off cylinder, seal support (15), centering disc
(13), spacer ring (19) and guide ring (20) together with seals
from piston (14). Take note of the sequence for reassembling.
Check inner cylinder surface (17) and piston surface (14).
Check seals and replace as necessary. Dirt or damage will
cause seals to wear out quickly.
Grease all parts lightly with silicone before reinstalling.
Tighten hexagon nut (16) to 18.5 ft.-lbs. (25 Nm).
Center bypass valve seat (23) within casing and tighten to
111 ft.-lbs. (150 Nm) with valve plug (24). Thereafter, insert
complete piston unit from the above side. Fit spring guide
(2) and flange (2A) along with plate springs (12), tighten
inner hexagon screws (3) at 36 ft.-lbs. (49 Nm).
to check and replace valves
Screw out plugs (24 or 28), pull out spacer pipe (28)
underneath plug (24 or 28). Check whether the valve plate
(29) underneath or the piston (14) are worn out. Remove
valve seats (23) and check sealing surfaces and o-rings for
damage. Replace as necessary.
to adjust pressure
The spring packing is pre-tensioned by means of the hand
wheel (6) while the pump is running and the gun is open (in
the case of more than one gun, all guns have to be open)
until required operating pressure is reached. If adjustment
of the selected nozzle sizes is correct, no water will flow
through the bypass. The hexagon nut (7) is then to be
locked to the spring guide (2).
IMPORTANT!
If the nozzle hole is too small, on no account
is the valve to be adjusted to an operating pressure higher
than that of the pump. It is advisable in this case to install
nozzles more suitable for this purpose.
06/22 22980(R).INDD
©
Copyright 2022 Giant Industries, Inc.
Giant Industries, Inc.
900 N. Westwood Ave.
Toledo, Ohio 43607
419-531-4600
419-531-6836 Fax
www.giantpumps.com
22980 & 22980R
DIMENSIONS (INCHES)
WARNING:
This product might contain a chemical known
to the State of California to cause cancer, and birth
defects or other reproductive harm.
For more information go to www.P65Warnings.ca.gov
DEFECT
CAUSE
REMEDY
Valve switches on &
off repeatedly when
gun is closed
Gun Leaking
Repair/Replace Gun
Leak in
Discharge Line
Identify & Fix Leak
Seal Ring (22) leaks
Kick-Back valve is
defective
Replace Seal Ring.
Check valve seat
(23), valve plate (29),
spring (30) & o-ring
(25).
Leakage at spring
guide
Piston Seal (22A)
Leaking
Replace Seal Ring
(22A)
Cylinder o-ring (18)
leaks
Replace o-ring (18)
Switches to Bypass
while gun is open
Nozzle too small/Too
much water
Install larger nozzle
Bypass valve worn
Replace piston (14),
bypass valve seat
(23) & o-ring (25)
Pressure gauge
reading jumps when
spray gun is shut off
Valve activation
pressure is set
higher than operating
pressure
Turn hand wheel to
operating pressure
level and secure with
locknut (7)
Dirt in valve
Clean valve of any
deposits. Grease
parts before
reassembly
