Actuator Control; Temperature Setting Range - Mitsubishi Electric PU(H)Y-P250YGM-A Service Handbook

-2- Actuator Control

(1) LEV Control
• The degree of LEV opening is set to the initial degree depending on the condensing pressure at start-up.
• After the start-up, the degree of LEV opening is controlled every minute so that the superheat detected by
the thermistors TH22 (liquid pipe) and TH23 (gas pipe) of the indoor unit can be within a certain range.
• Depending on the operating condition of the outdoor unit, a control other than the superheat control described
above may be performed.
• W hen suction or discharge temperature nears the target temperature, superheat control value rises and
LEV opening narrows.
• The degree of LEV full opening/closing is 41 pulses.
(2) Fan Control
Whether the thermostat is ON or OFF, the fan stays ON except during operation stoppage.
Exception: Fan stops when problem with the fan is detected (Error Code 4109).
* Fan problems may be experienced in the following situations: Surge breaker trip (51F) or malfunctions
of sub relays (Z1, Z2, or Z3.)
(3) Float Switch Control
The unit makes an error stop when the contact point (B contact) of the float switch loses its contact
(i.e. loosened floated parts, disconnected wire, unfastened connector etc.) for more than 1 minute or longer.
(4) Indicator Lamp
Indicator lamps on the front side of the unit indicate the operation status of the indoor unit.
Power Supply Lamp (White) : Lit upon power ON. Extinguished upon power OFF.
Operation Lamp (Green)
Error Lamp (Red)
Inspection lamp (orange)

-3- Temperature Setting Range

The temperature range can be set between 19 C (14 C) and 30 C using the remote controller when the suction
temperature control (or the discharge temperature control) is performed.
* Depending on the operating conditions, target temperature and actual discharge/suction temperatures may
not match. For example, even if the target discharge temperature is set at 14 C, if the load exceeds the
capability of the unit, the actual temperature will not reach 14 C.
-4- Emergency Operation Mode
The emergency operation is an operation that operates the unit temporarily depending on the error types
described later. The emergency operation is run automatically when the following errors are detected.
(1) Starting an Emergency Operation
When the following problems are detected, the system runs an emergency operation, displaying error codes.
During this operation, near normal operation is run, ignoring the following abnormal operation data. (Some
of the actuator will run at a fixed state during this time.)
Chart: Types of errors in which emergency operation can be run
Thermistor Error
(2) Stopping the Emergency Operation
Emergency operation mode is stopped in the following situations:
When abnormal mode is reset
* How to reset an abnormal mode
• When the operation is stopped by the remote controller or by the external input
A different type of error is detected during emergency operation
* i.e. when TH22 error is detected during emergency operation caused by TH21 error
When emergency operation disabled error is detected
: Lit during operation. Extinguished during stoppage.
: Lit when errors are detected in each refrigerant circuit. Extinguished during
normal operation or after error reset.
: Lit when the inspection switch of the indoor unit is ON (during inspection).
Extinguished when the switch is OFF (during normal operation).
Types of Errors
TH21 Open/Short Detection
TH22
TH23
TH24
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Error codes
5101
5102
5103
5104
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