Mitsubishi Electric PUHZ-W85VHA Service Manual page 19

Abnormal point and detection method
Error Code
Freezing/overheating protection is working
(1) Freezing protection <Cooling mode>
Abnormal if plate heat exchanger pipe
temperature (TH6) stays at -5: or lower
for 10 seconds or abnormal if plate heat
exchanger pipe thermistor (TH6) stays at
-2: or lower and compressor operation
frequency is minimum for 5 minutes
after compressor starts operating for 6
minutes.
(2) Overheating protection <Heating mode>
Abnormal if condensing temperature of
pressure sensor (63HS) detects
Tcond. : or more and compressor oper-
ation frequency is less than or equal to
30 Hz. Detection is inoperative during
defrosting.
P6
Tcond
stage-g
-19
Pipe temperature
Abnormal if the following conditions are
detected for continuously 3 minutes after
compressor starts operating for 10 minutes.
1. Cooling mode
-TH7 [ 2: and
T
63HS
TH3-TH7 [ 4: or T
TH32-TH6 [ 0: and
Compressor operation frequency is 61Hz or more.
2. Heating mode
P8
-TH32 [ 2: and
T
63HS
TH6-TH32 [ 1: and
TH7-TH3 [ 1: and
Compressor operation frequency is 61Hz or more.
T : Condensing temperature of pressure
63HS
sensor (63HS)
Thermistor
TH3: Liquid temperature
TH32: Inlet water temperature
TH6: Plate HEX Liquid temperature
TH7: Ambient temperature
Abnormal pressure of pressure sensor
(63HS)
Abnormal if pressure sensor (63HS) detects
0.1 MPa or less.
UE
Detection is inoperative for 3 minutes after
compressor starting and 3 minutes after
and during defrosting.
<Cooling mode>
1 Reduced water flow
· Clogged filter
· Leakage of water
2 Low temperature
· Low-load
· Inlet water is too cold.
3 Defective water pump
4 Defective outdoor fan control
5 Overcharge of refrigerant
6 Defective refrigerant circuit
(clogs)
7 Malfunction of linear expansion
valve
<Heating mode>
1 Reduced water flow
· Clogged filter
· Leakage of water
2 High temperature
· Over-load
· Inlet water is too warm.
3 Defective water pump
4 Overcharge of refrigerant
5 Defective refrigerant circuit
(clogs)
6 Malfunction of linear expansion
valve
stage-d
stage-e
stage-f
-18 -16 -15 -13 -12
stage-a stage-b stage-c stage-d stage-e stage-f stage-g
Tcond 63 61
1 Leakage or shortage of
refrigerant
2 Malfunction of linear
expansion valve
3 Refrigerant circuit is clogged
-TH3 < 0: and
with foreign objects.
63HS
w Clogging occurs in the parts
which become below freezing
point when water enters in
refrigerant circuit.
4 Disconnection of thermistor
holder.
1 Disconnection or contact
failure of connector (63HS)
on the outdoor controller
circuit board
2 Defective pressure sensor
3 Defective outdoor controller
circuit board
19
Case
<Cooling mode>
12 Check water piping.
3 Check water pump.
4 Check outdoor fan motor.
5~7 Check operating condition of refrigerant
7 Check linear expansion valve.
<Heating mode>
12 Check water piping.
3 Check water pump.
45 Check operating condition of refrigerant
circuit.
6 Check linear expansion valve.
stage-b
stage-c
-11 -10 -8 -7 -3
Ambient temperature (TH7)
59 57 54 51 48
1 Check intake superheat.
Check leakage of refrigerant.
2 Check linear expansion valve.
3 After recovering refrigerant, remove water
from entire refrigerant circuit under vacuum
more than 1 hour.
4 Check temperature display on outdoor
controller circuit board.
Temperature display is indicated by setting
SW2 of outdoor controller circuit board.
Check the holder of thermistor.
1 Check connection of connector (63HS) on
the outdoor controller circuit board.
Check breaking of the lead wire for thermistor
(63HS).
2 Check pressure by microcomputer.
(Pressure sensor/ 63HS)
(SW2: Refer to 8-7.)
3 Replace outdoor controller board.
Judgment and action
circuit.
stage-a
-2
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