PSI System Controls and Diagnostics
A500 User Manual
A500_UM_090115 Page 55 of 61
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Maintenance
The A500 does not require regular maintenance. However if the unit is operating in an
environment where there may be dust in the air, you should check the fan filter for blockage
periodically. It is normally sufficient to clean the filter without opening the unit using a vacuum
cleaner with small nozzle attachment.
The A500 is fitted with a 1.1 A automatically resetting positive temperature coefficient (PTC)
fuse in the 24 VDC input. No user intervention is required if the fuse operates due to over-
current. The fuse will reset when the over-current condition ends.