Mitsubishi Electric PUHY-P250YHM-A, Data Book

Page: 6 / 101

4
4
Fan control
The unit may be forced to operate in the heating mode to prevent cold draft when the return air temperature
(outside air temperature sensor reading) reaches 5˚C
[41˚F] or below. At the time of factory shipment, fan setting is
made so that the fan will stop during the defrost cycle and when there is a problem with the entire refrigerant
systems.
See below for switch settings and unit operation.
5
Sample operation patterns (supply air temperature control)
The unit will follow the operation control pattern below at the nominal air flow rate and the preset temperature of
22˚C
[72˚F] . Use it only as a guide. The range changes with the air flow rate and preset temperature.
6
Thermo-ON/OFF conditions (supply air temperature control)
*Settings in the shaded areas indicate factory settings.
Specifications
Forced heating
operation
Fan operation
during defrost
·
Forced heating
operation disabled
·
Fan stays on
when there is an
error. (The fan
stops when there
is a problem with
the fan or a
communication
error.)
·
The fan turns off
when the entire
refrigerant system
is in the defrost
cycle
·
Forced heating
operation enabled
·
Fan turns off when
there is a problem.
·
The fan turns on
during defrost
SW
SW1-7
SW3-4
Notes
When the return air temperature
reaches 5˚C
[41˚F] or below, the unit will
be forced to operate in the heating
mode to prevent cold draft regardless of
the actual operation mode setting.
If the return air temperature reaches
6˚C
[43˚F] or above, the units will
resume operation in the selected mode.
The fan will stop when there is an error,
regardless of the outside temperature.
Operation
OFF ON
*Operating the fan during the defrost cycle can cause cold outside air to be delivered into the room, and it can also
delay normal unit operation to be resumed after the defrost cycle is completed, both of which can greatly decrease
the room temperature.
Outside temperature
[˚F]
(˚C)
Cooling mode
Forced
heating
operation
Cooling Thermo-OFF
Fan mode
Heating Thermo-OFF
Heating operation
Cooling operation
Controllable Note 1
Controllable
Thermo ON/OFF
Thermo ON/OFF
Supply air
temperature rises.
Forced
heating
operation
Heating mode
Fan mode
<Cooling operation>
32 41 50 59 68 77 86 95 109
0 5 10 15 20 25 30 35 43
Note 1 Thermo-ON: Controllable; Thermo-OFF: Forced heating
Preset temperature
Thermo-OFF conditions
(
1
,
2
, or
3
)
Thermo-ON conditions
14 ~ 30˚C [ 57 ~ 86˚F]
1
Outside temp. < Preset temp.+0.0
2
Supply air temp. < Preset temp.-2˚C lasting for consecutive 10 minutes
3
15 or more minutes after startup AND Supply air temp. < Preset temp.-5˚C
Supply air temp. > Preset temp +2˚C AND Return air temp. > Preset
temp.+1.5˚C, AND at least 3 minutes have passed since Thermo-OFF
<Heating operation>
Preset temperature
Thermo-OFF conditions
(
1
,
2
, or
3
)
Thermo-ON conditions
17 ~ 28˚C [ 68 ~ 82˚F]
1
Outside temp. < Preset temp.+0.0
2
Supply air temp.> Preset temp.+5˚C lasting for consecutive 10 minutes
3
15 or more minutes after startup and Supply air temp. > Preset temp.+10˚C
Supply air temp. < Preset temp.-2˚C AND Return air temp. < Preset temp. -
1.5˚C AND at least three minutes have passed since Thermo-OFF