Notes On Selecting Equipments - Mitsubishi Electric PFAV-P250VM-E Data Book

3. Notes on selecting equipments

(1) Notes on using the Fresh Air Intake type units
1Fresh air intake type indoor units supply pretreated outside air into the room. This type of units are not designed to
handle internal thermal load. Use other types of air conditioning units (e.g., CITY MULTI system) that are capable
of handling internal thermal load in combination with the Fresh Air Intake type units.
<Fresh Air Intake type sample installation>
2The control mode is selectable between room temperature control and supply air temperature control. The default
mode is room temperature control. Install the supplied thermistor in a location that allows the sensor to measure
the representative room temperature.
3
·
Fresh air intake type units are intended to be used in an environment at a temperature of 0˚CDB
[32˚FDB] or above. If the units are operated in the fan mode at the temperature below 0˚C[32˚F],
condensation may form on the panel under certain conditions. Use caution so that the
condensation will not drip on appliances around the unit.
·
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. The fan will
stop during the defrost cycle and when there is a problem with the entire refrigerant systems.
The fan can be set to operate in the conditions above by making certain switch settings if a
Common items
sudden supply of cold air into the room during the heating season will not be a problem.
·
Note that untreated outside air may be delivered directly into the room upon Thermo-OFF. Use
extra caution when the outside temperature is low. Direct exposure to outdoor air may have an
adverse effect on health or cause food spoilage.
·
Fresh air intake type units are not equipped with a dehumidifying function. Take appropriate
measures to keep condensation from forming on the supply air grill and other parts that are
subject to condensation. Line the supply and return air ducts with insulation to prevent
condensation.
·
Install the thermistor that is supplied with the indoor unit. Check that Switch 7-2 is set to OFF.
·
Install the thermistor in a location that allows the sensor to measure the representative room
temperature.
Room
·
The unit will go into the forced Thermo-OFF mode when the return air dry bulb temperature
temperature
(outside air temperature sensor reading) is 21˚C[70˚F] or below during cooling OR 20˚C[68˚F] or
control
above during heating.
(factory setting)
·
The settable temperature range on the remote controller is as follows: Cooling 19 - 30˚C[66 -
86˚F]; Heating 17-28˚C[63 - 82˚F].
·
Indoor temperature and humidity can fluctuate greatly depending on the outside air load.
·
Connect the connector of the supply air temperature sensor that is built in on the indoor unit to
the control board. Turn Switch 7-2 to ON.
·
The unit will go into the forced Thermo-OFF mode and operate in the Fan mode when the return
air dry bulb temperature (outside air temperature sensor reading) is 14˚C[57˚F] or below during
cooling OR 28˚C[82˚F] or above during heating.
·
Supply air temperature may fluctuate, depending on the temperature/humidity of the outside air
or on other operating conditions. Units may go in and out of the Thermo-ON/OFF mode when
the following conditions are met: The difference between the outside temperature and the preset
Supply air
temperature is less than approximately 6˚C[43˚F] due to excess capacity. They may change
temperature
depending on the air flow rate and preset temperature.
·
control
Supply air temperature normally appears on the remote controller. When the unit operation is
not stable, this temperature may blink on the display and can be mistakenly interpreted as an
error. If this is a problem, change the setting to suppress the temperature display. Refer to the
section "How to use the remote controller" in the Instructions Manual for how to make the setting.
·
The settable temperature range on the remote controller is as follows: Cooling 14 - 30˚C[57 -
86˚F]; Heating 17-28˚C[63 - 82˚F].
·
Depending on the air conditioning load, outside temperature, and due to the activation of
protection functions, the desired preset temperature may not always be achieved.
Supply air temperature sensor*1
(Built in, not connected at the time of factory shipment)
Outside air damper
Fresh air intake type indoor unit
Outside air temperature sensor (built in)
3
Discharge air
Remote controller
(built in)
Temperature sensor*2
(supplied)
Indoor temperature controlling unit
*1 Enable to use the supply air
temperature control mode
*2 Enable to use the room
temperature control mode