Groundsmaster 4500--D/4700--D Hydraulic SystemPage 4 -- 65
Procedure for Cooling Fan Circuit Test
1. Make sure hydraulic oil is at normal operating tem-
peraturebyoperatingthemachineforapproximatelyten
(10) minutes. Make sure the hydraulic tank is full.
2. Park machine on a level surface with the cutting
decks lowered and off. Make sure engine is off and the
parking brake is applied.
CAUTION
Prevent personal injury and/or damage to equip-
ment. Read all WARNINGS, CAUTIONS and Pre-
cautions for Hydraulic Testing at t he beginning
of this section.
3. Raiseandsupporthoodtogainaccesstofancontrol
manifold(Fig.54).Connecta5,000PSI(345bar)gauge
with hydraulic hose attached to test fitting in port G on
rear of manifold.
4. Start the engine. Move throttle to full speed (2870
RPM).
5. While monitoring the pressure gauge and using a
phototac to identify the cooling fan speed, disconnect
the w ire harness connector (white/violet and black
wires) from the proportional relief v alve solenoid at fan
controlmanifold(portTS).Bothfanspeedandpressure
should increase and stabilize after the solenoid is dis-
connected.
PRESSURE GAUGE READING TO BE approxi-
mately 3000 PSI (207 bar)
PHOTOTAC (fan speed) READING TO BE approxi-
mately 2800 RPM
6. Stop engine and record test results.
7. If pressure rises to approximately 3000 PSI (207
bar) but fan speed is low, consider that the fan motor is
worn or damaged. If pressure and fan speed are both
low, consider that gear pump P4 is worn or damaged
(see Gear Pump P4 Flow Test in this section).
NOTE: Ifpressureandfans peedarebothlowandgear
pump P4 flow proves to be correct (see Gear Pump P4
Flow Test in this section), suspect that seals in fan con-
trolmanifold areleakingorfaulty(seeFanC ontrolMan-
ifold Service in the Service and Repairs section of this
chapter) or that fan motor is worn or damaged.
8. When testing is complete, remove pressure gauge
from manifold fitting and reconnect wire harness to pro-
portional relief valve solenoid. Lower and secure hood.
1. Fan control manifold
2. Test fitting (port G)
3. PRV solenoid
Figure 54
2
1
3
Hydraulic
System
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