17
Installation, Operation & Maintenance Manual
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Fault Finding Continued:
DECOMMISSIONING & DISPOSAL
Fault
Possible Cause
Remedy / Action
No heating or cooling
Temperature controller.
Contact controls specialist.
No air volume.
Inspect drive belts. Check motor winding
resistance.
Pressure switch failure.
Inspect fan pressure switch and tubing,
replace as necessary.
Refrigeration fault.
Contact refrigeration specialist.
Low heating output or Air
Volume
Compressor fault indication.
Contact refrigeration specialist.
Dirty filters.
Replace filters.
Defective Heat Recovery device.
Thermal Wheel:
Check wheel rotation.
Recuperator:
Check bypass damper closed on heating
demand. Replace if faulty.
Frost coil not operational (if
applicable).
Contact controls specialist.
Re-heat coil not operational.
Investigate operation of control valve.
Seasonal Shutdown
Before an extended period of non-use, it is recommended to reduce the system to
minimum
capacity using the regulation/control system, then set any dampers to run
in a recirculating arrangement (if applicable) in order to reduce risk of frost.
It is also advisable to close all control valves, then switch off any recirculating
pumps, followed by closing all fresh water and manual valves. Small empty spaces
suffer from a risk of frost, so it is a good idea to blow compressed air through them, if
available, until they are free from residue.
Allow the fan to run until all surfaces are dry. Switch off the mains switch and lock
everything up.
If the unit is not to be used for several months and the fan(s) have a belt (most non-
EC fans), then it is advisable to either slacken or remove the fan belt to avoid
tensioning damage during storage.
End of Life Disassembly
Before starting disassembly, the AHU and all built-in components must be
disconnected from the mains and all live connections removed by a qualified
electrician. Additionally, all media-bearing components must be completely emptied.
This must be conducted by a specialized company which can carry out the
professional disposal of water with antifreeze, and refrigerants.
The AHU can then be dismantled on-site into individual unit modules or into its
component parts. It is advisable for this to be carried out by a specialized company,
familiar with the environmentally friendly disposal of all component parts.
