Sullair 750H - Page 89

SECTION 5 600H, 700HH, 750, 750H, 750HH, 825, 900H, 1050 USER MANUAL
89
Improper unloading with
an excessive pressure
build-up causing pressure
relief valve to open
Fluid charge lost from spring chamber
on inlet valve pressure regulating valve
is set too high
Add fluid to inlet valve spring chamber by
removing plugs in the top of the spring chamber
and filing with compressor fluid.
Some fluid may leak from the control regulator at
first but will stop leaking when fluid level in the
spring chamber equalizes.
Running blowdown valve pressure
regulating valve set too high
Readjust.
Leak in control system causing loss of
pressure signal
Check control lines.
Worn seals in inlet valve. Replace seals (kit
available).
Defective pressure regulating valves; repair valves
(kits available).
Inlet valve jammed Free or replace valve.
Restriction in the control system Check all control lines and components.
Ice and other contaminants could cause
restrictions.
Defective pressure relief valve Replace pressure relief valve.
Insufficient air delivery Plugged air filter Replace.
Plugged air/fluid separator Replace separator element and also change
compressor fluid and fluid filter at this time.
Defective pressure regulator Adjust or repair.
Engine speed too low Readjust engine speed.
Control air cylinder defective Replace cylinder.
Excessive compressor
fluid consumption
Clogged return line Clear orifice.
Leak in the lubrication system Check all pipes, connections and components
Separator element damaged or not
functioning properly
Change separator element.
Defective minimum pressure/check
valve
Repair or replace.
Fluid receiver tank overfilled Drain to proper level.
Compressor overheating Loose or broken fan belt Tighten or change belt
Dirty fluid cooler core Clean core thoroughly.
Dirty aftercooler Clean core thoroughly.
Dirty radiator core Clean core thoroughly.
Faulty thermostat element Change thermostat element.
Plugged fluid cooler tube (internal) Clean tube thoroughly.
Low receiver tank fluid level Refill.
Plugged compressor fluid filter Change element.
Table 5-2: Troubleshooting Chart
SYMPTOM PROBABLE CAUSE REMEDY