Champion HR3-6, Operation & Maintenance Manual

12

GENERAL MAINTENANCE NOTES (CONT'D)

CENTRIFUGAL UNLOADER AND UNLOADER PRESSURE RELEASE VALVE: 

The centrifugal unloader Is operated by two governor  weights.  It is totally enclosed and lubricated from
the crankcase of the compressor.  When compressor starts, the governor weights automatically open
compressing the main spring, allowing the unloader pressure release valve to close. When the compressor
stops, the  main spring returns the governor  weights to normal position opening the unloader pressure
release valve and unloading the compressor.  This prevents overloading the motor when starting.  If air
continues to escape through the governor or unloader pressure release valve while operating, this is an
indication that the unloader pressure release valve is not closing tightly and may be held open by foreign
substance which has lodged on the seat. In order to correct this, remove the governor release valve cap,
giving access to unloader pressure release valve spring and ball.  Clean thoroughly and return parts in the
same order in which they were removed.  Loose drive belts can also cause unloader to leak by preventing
the compressor from reaching proper speed.  (See "BELTS" above.)

CHECK VALVE:

The check valve closes when the compressor stops operating, preventing air from flowing out of the tank
through the pressure release valve.  After the compressor stops operating, if air continues to escape
through the release valve, it is an indication that the check valve is leaking.  This can be corrected by
removing check valve and cleaning disc and seat.  If check valve is worn badly, replace same.

WARNING

Before removing check valve be sure all air pressure in unit is relieved and power is disconnected.  Failure
to do so may result in injury or equipment damage.

THE INTERSTAGE PRESSURE RELIEF VALVE 

is provided to protect against interstage over pressure and is

factory set for maximum pressure of 75 PSIG.

DO NOT RESET

If the pressure relief valve pops, it indicates trouble.  Shut down the unit immediately and determine and
correct the malfunction.  Inspect the head valves.  Serious damage can result if not corrected and can lead
to
complete destruction of the unit.  Tampering with the interstage pressure relief valve, or plugging the
opening destroys the protection provided and voids all warranty.

LUBRICATION OF COMPRESSOR:

Fill crankcase to proper level as indicated by oil sight gauge.  Keep crankcase filled as required by usage.