Mitsubishi Electric CAHV-P500YA-HPB, Service Handbook

Page: 86 / 160

[
VII
Control ]
- 79 -
HWE10060 GB
[2] Operating characteristics and Control Capabilities
Outline of Control Method
-1- Operating characteristics
Function Component Symbol Control/
Detection
Ac-
tion
Unit Trigger condition
Unit
protection
Pressure
switch
High-pressure
switch
63H1 HP 63H1 ON MPa (2.95)
OFF MPa 3.85
High-pressure
sensor
63HS HP 63HS OFF MPa -
Low-pressure
sensor
63LS LP 63LS OFF MPa Œ
The low pressure has dropped below 0.06 MPa
within 30 seconds of compressor start-up.
Œ
The low pressure has dropped below 0.06 MPa
within 30 seconds of a defrost cycle.
Œ
During water heating, the low pressure has
dropped by 0.02 MPa after the air-side heat ex-
changer inlet temperature has reached -31ºC.
Œ
During water heating, the low pressure has
dropped by 0.02 MPa after the air-side suction
pipe temperature has reached -33ºC.
Œ
The outside temperature of 10ºC or above has
been detected for 20 minutes and the low pres-
sure has dropped below 0.06 MPa during water
heating.
Compressor overcurrent relay Compressor
current
OFF A 33
Built-in thermistor on the fan
motor (Stops the motor)
Built-in
thermistor on
the fan motor
ON ºC 90 15
OFF ºC 145 5
Thermis-
tor
Discharge refrig-
erant temp.
(Discharge temp.
overrise protec-
tion)
TH1
TH5
Discharge
gas temp.
OFF ºC
Œ
A discharge gas temperature of 120ºC or above
has been detected for 30 seconds while the com-
pressor is in operation. (Preliminary abnormal
stop)
If this happens three times, the unit will make an
abnormal stop.
Œ
If a discharge gas temperature of 125ºC or above
was detected, the unit will make an abnormal
stop.
Air-side HEX inlet
temp.
(vacuum protec-
tion)
TH4
TH8
Air-side HEX
inlet temp.
OFF ºC A heat-side heat exchanger inlet temperature of
-33ºC was detected.
Suction temp.
(vacuum and
freeze-up protec-
tion)
TH2
TH6
Suction gas
temp.
OFF ºC A suction gas temperature of -36ºC was detected.
Compressor shell
temp.
(compressor
floodback protec-
tion)
TH3
TH7
Comp. shell
temp.
OFF ºC A shell bottom SH temperature of 10ºC or below
has been detected for 40 minutes while the com-
pressor is in operation.
Inverter heatsink
temp
THHS INV. heat-
sink temp.
OFF ºC A temperature of 80ºC or above has been detected
for 10 minutes or a temperature of 90ºC or above
was detected.
Refrigerant
circuit
control
Liquid injection circuit LEV2
SV2
Discharge
gas temp.
ºC Injection is controlled by referencing the discharge
gas temperature.
Pump
control
Inlet (freeze-up protection) TH10
TH12
Water inlet ON ºC 3
OFF ºC 5
Outside temperature thermis-
tor
TH9 Outside
temp.
ON ºC 1
OFF ºC 3
Freeze-up protection circuit The pump turns on when the water inlet tempera-
ture has reached below the "ON" threshold AND
the outside temperature has reached below the
"ON" threshold when the compressor is stopped.