22
TROUBLE CHART(Cont)
Trouble Cause Remedy
1) Failure to raise
load. (Cont)
1 h) Relief valve
setting incorrect
on double- acting
hoist only.
1h) See following.
1j) Pump will not pro-
duce pressure.
1j) See following.
When any work is to be done on body or hoist and body is fully or
partly raised, body must have both props securely set or be blocked
securely so it cannot fall. In addition, the HOIST control lever must
be in neutral with the hoist lever lockout engaged in the "lock" posi-
tion and the PTO disengaged.
REMEDY
Observe CAUTION above and check pressure in system.
1715 DA, 1721 DA, 1821 DA and 1824 DA-HD
The double-acting hoists have a relief valve in the system. Discon-
nect hose from base end of cylinder and plug cylinder port. Con-
nect hose to a 0-3000 psi (0-20 684 kPa) pressure gage. Run pump
at about 300 rpm. Place hoist control lever into RAISE position
and allow pressure to build up against the relief valve (only for a
few seconds). If pressure does not build up properly, adjust relief
valve. To adjust the relief valve, which is installed in the hoist con-
trol valve, remove acorn nut, and loosen jam nut. Use screwdriver
to turn adjustment screw clockwise to increase pressure, counter-
clockwise to decrease pressure. After adjusting to proper pressure,
tighten jam nut and replace acorn nut. If pressure still does not
build up properly, pump may be defective. Replace pump.
1715, 1721, 1821 and 1824 HD
The single-acting hoists do not have a relief valve. Disconnect hose
from base end of cylinder and plug cylinder port. Connect hose to
a 0-3000 psi (0-20 684 kPa) pressure gage. Run pump at about 300
rpm. Gradually feather control valve into raise position until pres-
sure gage reads the minimum pressure required for the specic
hoist being tested. If pressure does not build up properly, the pump
may be defective. Replace pump.
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