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Fault Finding
If the Thermoscreens Heat Pump Air Curtain System does not operate as expected refer
to the fault finding table below:
Symptom
Electrical power is not switched on to
the Mitsubishi Electric City Multi system
and at the local electrical isolator next to
the Thermoscreens Air Curtain
Air curtain
Air curtain is not switched On
fans do not
operate
Remote ON/OFF or ENABLE/DISABLE
wiring to terminals 3, A1 & A2 not wired
up correctly
Problem with air curtain fan motor(s),
internal wiring, controls or fan speed
door switch if fitted
Air curtain has been running for less
than 20 minutes and is still warming up
or cooling down
Air curtain is set to Fan-Only on PAR-
31MAA/U02MEDA Remote Controller,
BMS System or Centralised Controller
Target temperature is set incorrectly,
Air curtain
i.e. too low for heating or too high for
discharge air
cooling
stream is not
heating or
The operating mode is set incorrectly,
cooling when
i.e. set on COOL when heating is
required
required
Condensate Alarm circuit is open circuit
and air curtain will not COOL or HEAT
Air Curtain filters and/or coil is dirty.
Error Code 2503 indicating condensate
alarm from condensate pump alarm
Mitsubishi
Electric
system
system is
indicating an
A variety of error codes can occur
error code
because of a fault within the air curtain
If the Heat Pump Air Curtain system is still not operating correctly call for a Mitsubishi
Electric Service Agent.
T9901075-2-3 UK
Possible Cause
Action Required
Switch on power to all
components in the heat pump
system and wait for system to
boot-up
Switch on the air curtain using
the Remote Controller, BMS
System or Centralised
Controller
Wire terminals 3, A1 & A2
correctly – see Wiring
Diagrams
Use wiring diagram to
investigate possible cause of
fault
Give system sufficient time to
reach operating condition
Check schedule on Controller
and amend if necessary
Adjust the target temperature
on the Remote Controller,
BMS System or Centralised
Controller
Select the correct mode for the
conditions on the Remote
Controller, BMS System or
Centralised Controller
Rectify alarm circuit which
must be closed circuit for heat
pump system to operate
Service air curtain as
described in Section –
Servicing, Pages 33 to 35
Inspect air curtain condensate
tray and condensate pump,
service or repair if necessary
Refer to Mitsubishi Electric
Service Manual to understand
fault, then inspect and repair
air curtain if there is a fault
Page 36 of 38
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