T9901085-1-3 UK
Page 36 of 38
Fault Finding
If the Thermoscreens Heat Pump Air Curtain System does not operate as expected refer
to the fault finding table below:
Symptom
Possible Cause
Action Required
Air curtain
fans do not
operate
Electrical power is not switched on at
the Mitsubishi Electric Outdoor Unit
Switch on power to Mitsubishi
Electric Outdoor Unit and wait
for system to boot-up
Air curtain is not switched On
Switch on air curtain using the
PAR-W21 or PAR-30 Remote
Controller, BMS System or
Centralised Controller
Air Curtain fans are not wired to
operate, no wire link on fan terminals in
air curtain or a 3-Speed Fan Switch
Wire in the wire link or a 3-
Speed Fan Switch – see
Wiring Diagrams
Problem with air curtain fan motor(s),
internal wiring, controls or fan speed
door switch if fitted
Use wiring diagram to
investigate possible cause of
fault
Air curtain
discharge air
stream is not
heating or
cooling when
required
Air curtain has been running for less
than 15 minutes and is still warming up
or cooling down
Give system sufficient time to
reach operating condition
Weather Compensation Control:
Outdoor air temperature is not cold
enough for discharge air to be heated
This is normal and shows that
air curtain is saving energy by
working in Fan only mode
Discharge Air temp Control, or Inlet Air
Control or Room Air Control: Target
temperature is set incorrectly, i.e. too
low for heating or too high for cooling
Adjust the target temperature
on the Remote Controller,
BMS System or Centralised
Controller
The operating mode is set incorrectly,
i.e. set on COOL when heating is
required, or vice versa
Select the correct mode for the
conditions on the Remote
Controller, BMS System or
Centralised Controller
Air curtain will not COOL, if installation
allows (must have condensate disposal
system fitted)
Rectify condensate alarm
circuit which must be open
circuit for air curtain to operate
in cooling. Also check plug is
removed from CNX5 on PCB
Air Curtain filters and/or coil is dirty.
Service air curtain as
described in Section –
Servicing, Pages 33 to 35
Mitsubishi
Electric
system is
indicating an
error code
Error Code indicating condensate alarm
from condensate pump alarm system
Inspect air curtain condensate
tray and condensate pump,
service or repair if necessary
A variety of error codes can occur
because of a fault within the air curtain
Refer to Mitsubishi Electric
Service Manual to understand
fault, then inspect and repair
air curtain if there is a fault
If the Heat Pump Air Curtain system is still not operating correctly call for a Mitsubishi
Electric Service Agent.
