T9901085-1-3 UK
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The air curtain can also be set up on site during commissioning to operate under
Inlet Air
Temperature Control
or
Room Air Temperature Control
and is then used with a
Mitsubishi Electric PAR-30 MAA Remote Controller. The following functions are available:-
On/Off control of the Mitsubishi Electric heat pump system
Mode change between Heating mode and Fan only mode, with Cooling mode also
available if enabled during commissioning and with a condensate disposal system
Capacity control of the Mitsubishi Electric heat pump system
Temperature monitoring of the inlet air entering the heat pump air curtain, or the room
air temperature at the remote controller
Signal for when the outdoor unit is in defrost mode so the defrost cycle auxiliary heater
(if enabled) can provide partial heat back-up during the few minutes of defrost.
Error signal for if the Mitsubishi Electric heat pump system has a problem
Refer to a Mitsubishi Electric agent if the air curtain is to be controlled via a Building
Management System (BMS) or Centralised Controller.
It should be noted that during heating mode, if the outdoor unit goes into its defrost cycle
during cold weather, the air curtain fans will continue to operate to maintain the all-
important air stream across the doorway. It is this air stream, particularly towards the top of
the doorway, which is so effective at stopping buoyant warm air from inside the building
escaping to outside and wasting energy and also in reducing airborne contamination.
The temperature of the discharge air can be low during the 6 to 7 minute defrost cycle
period that may occur every few hours under particular outdoor weather conditions but this
has rarely become an issue with the end user and is really only a perceived problem.
There is a defrost cycle auxiliary heater fitted in the air curtain which is disabled when the
air curtain is delivered. If there are concerns for a particular installation this defrost cycle
auxiliary heater can be enabled during site commissioning and this will maintain the
discharge air at a higher temperature during the defrost cycle. A 3-phase electrical supply
is then required to power the air curtain.
Point of Information:
If used, an auxiliary defrost heater may seem counter-productive for
a heat pump system. When put into context, however, the auxiliary heater fitted is of low
output for the size of the air curtain, it will just temper the discharge air and is only used for
a few minutes a day during a small period of the year. Tests at the Building Research
Establishment (BRE) test house on the heat pump air curtain system showed that even
with the auxiliary heater cutting in during defrost, as it has to during their EN14511
performance test, the annual seasonal COP was hardly affected.
Cooling is possible if the air curtain is modified during commissioning to operate under
Inlet Air Temperature Control
or
Room Air Temperature Control
. It will not operate in
cooling if set-up to operate under
Weather Compensation Control
or
Discharge Air
Temperature Control
, which is how the air curtain is supplied.
The air curtain is supplied with its cooling mode disabled, although an integral condensate
drain tray is fitted inside the air curtain so it could be used in cooling mode during warm
weather, if so desired. This should be decided at the design stage as a condensate drain
system will need to be installed if cooling is required and extended to a suitable drain by
the installer. The condensate can be drained by gravity by connecting suitable condensate
hose onto the 15mm drain pipe on the condensate drain tray inside the air curtain. If a
gravity condensate drain is not visually suitable it will be necessary to remove condensate
using a condensate pump, supplied and fitted by the installer. The condensate pump can
