HAC 4500 Service Note 1201-022
Quantum Design
Service Note 1201-022, Rev. A0
1
November 2, 2011
Routine Outdoor Helium Compressor Maintenance
Instructions
Introduction
Every month of operation the outdoor compressor of the HAC4500 will need to be thoroughly
cleaned and serviced to ensure many years of reliable operation. This maintenance is best performed
by a trained Heat, Ventilation and Air Conditioning (HVAC) technician or building facility
personnel.
In practice, the HAC 4500 maintenance should be accomplished in approximately 1.5 hours and will
not require the PPMS EverCool II system to be warmed up. This Service note can be used as a
guideline for an HVAC technician to familiarize himself with the different routine maintenance
requirements of the HAC 4500 outdoor helium compressor.
Tools Needed
o
Medium size Philips screwdriver
o
Water Hose
Parts Needed
o
Spare 8-32 screws (zs-8csm.38tp)
I. Scheduling a maintenance event
In the PPMS EverCool II the most evident symptom that Cold Head maintenance might need to
be performed is that the system will not be able to maintain a constant liquid helium level.
II. Shutting down the system for Service Maintenance
The Outdoor Compressor unit maintenance should be scheduled every 2500 hours of operation
or when overheating of the compressor capsule is observed. The maintenance can be
accomplished in just about two hours and should not require the PPMS EverCool II system to be
completely warmed up.
1.
Set the system in standby mode from MultiVu by clicking Instrument
Æ
Shutdown
Æ
click
OK.
2.
Power down the indoor compressor by toggling the switch in the back of the indoor unit.
3.
Power down high voltage power by turning off the high voltage breaker. WAIT FOR 30
MINUTES BEFORE PROCEEDING TO THE NEXT STEP!! This will allow all the
capacitors in the compressor discharge to a safe level before opening the fuse bay.
