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MALFUNCTIONS AND CORRECTIVE ACTIONS
Malfunction
Fan does not run
Low air flow
from fan-coil unit
Fan-coil unit noisy
Fan-coil unit
does not heat
(sufficiently)
Fan-coil unit
does not cool
(sufficiently)
Fan-coil unit leaks
in the cooling mode
Room temperature
fluctuates
Possible causes
Fan coil unit not switched on
No power
Cabling not connected
The supply is stopped by the float switch
Low fan speed
Air ducting obstructed
Filter dirty
Hight fan speed
Low air discharge temperature
Air discharge system obstructed
Fan bearing defect
Filter dirty
Fan not switched on
Heating fluid not hot
Low water flow rate
Low setpoint temperature
Controller or sensor positioned near heat source
Filter dirty
Fan not switched on
Cooling fluid not cold
Low water flow rate
High setpoint temperature
Control located in cold air
(e.g. near door)
Filter dirty
Condensate tray dirty
Cold water lines not insulated
Unit not suspended horizontally
Condensate drain plugged
Condensate pump pumps no water
Condensation on air register
The control located at wrong place
(e.g. at doors or in the airdischarge area)
High heating fluid temperature
Independently controlled units
connected to same water line
(e.g. radiators with thermostatic valves)
Corrective action
Switch on fan-coil unit
Check fusing/mains power
Connect cabling (qualified person only)
Verify the float
Select higher fan speed
Clear air ducting, for unrestricted air flow
Replace or clean filter
Select lower fan speed
Increase temperature setting of control
Clear air discharge system
Call field service
Replace or clean filter
Switch on fan
Switch on boiler
Switch on recirculation pump
Vent heating system
Check pump throughput
Check water distribution
and reset pressure losses in different lines
Increase control setpoint temperature
Relocate the control
Replace or clean filter
Switch on fan
Switch on chiller
Switch on recirculation pump
Vent system
Check pump throughout
Check water distribution
and reset pressure losses in different lines
Lower control setpoint temperature
Relocate the control
Replace or clean filter
Clean condensate tray
Insulate cold water lines
Realign unit and suspend unit horizontally
Check condensate drain for sufficient slope,
clean and refill trap
Check power supply in terminal box and at pump
Check pump for dirt in the intake area
Check pump start-up
Check float switch for correct operation
Increase water flow temperature
Increase angle between air register stats and ceiling
Use coated air register
Increase fan speed
Relocate control to place where room temperature is representative
(remote from fan-coil unit)
Add or reset
maximum and minimum supply air temperature sensors
Reset boiler control
Split water supply;
if impossible use flow control valves on other units
and increase system pressure
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