Champion R30D Operation Maintenance Manual & Parts List page 14

GENERAL MAINTENANCE (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.
Before removing check valve be sure all air is drained out of tank 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.
COMPRESSOR LUBRICATION: Fill crankcase to proper level as indicated by oil sight gauge. Keep crankcase
filled as required by usage. It is recommended that only Champlub recip lubricant be used. This is a 30-
weight, non-detergent industrial oil with rust and oxidation inhibitors specially formulated for reciprocating
compressors. Do not mix oil types, weights or brands.
MOTOR LUBRICATION: Long time satisfactory operation of an electric motor depends in large measure on
proper lubrication of the bearings. Bearing grease will lose its lubricating ability overtime, not
suddenly. Refer to the motor manufacturer's instructions for the type of grease and lubrication
intervals.
PILOT VALVE: The pilot valve actuates the head unloader mechanism to provide a means of stopping
or starting the compression of air by the compressor without stopping or starting the electric motor.
WARNING
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