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7. FAULTFINDING
7.1 Introduction
Normally an operation fault will give an alarm in the display of the control panel. For
details, please refer to section 4 Controls in this manual.
7.2 Fault finding
Alarm
Service
Fan
Frost
Fire
HP/ LP
Compressor
1)
If the frost thermostat is manual, you have to reset the thermostat before starting the
unit. The thermostat is normally located on the upper deck of the unit near the heating coil.
2)
The fire thermostat must be reset before the unit is started again. Press the red button
on the thermostat to reset. The thermostats are located in the exhaust (70°C thermostat)
and supply (40°C) air.
3)
The HP pressostat has to be reset before the
compressor can start again. The red reset
button (1) is placed inside the unit, just above
the compressor.
Problem
Filter is dirty
Fan stopped
Valve not opening
1)
No hot water
Return air
temperature > 40°C
2)
Supply air
temperature > 70°C
HP pressure over
24 bar
3)
LP pressure under
1.5 bar
Cause
• Filter blocked
• Thermal overload
• Defect actuator
• Valve stuck
• Pump not working
• Boiler problem
• Fire in the building
• After heating coil not
working correct at low
air volume
• Fire in the unit
• Air volume too small
• Blockage in cooling
circuit
• Outside temperature too
high
• Leakage in the cooling
circuit
• Evaporator iced up
46
Action
• Change filter
• Wait until motor has cooled
down. Start the unit. If fan
stops quickly again
change/repair motor
• Change/Repair actuator
• Change/Repair valve
• Change/Repair pump
• See boiler manual
• Check reason for high
temperature in return air
duct
• Check heating coil controls
• Check air volume
• Check/repair cooling circuit
• Reset pressure switch
• Repair cooling circuit
• De-ice evaporator/check
de-icing function
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