Mitsubishi Electric PUHZ-W50VHA Service Manual page 29

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
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
2 Low temperature
3 Defective water pump
4 Defective outdoor fan control
5 Overcharge of refrigerant
6 Defective refrigerant circuit
7 Malfunction of linear expansion
<Heating mode>
1 Reduced water flow
2 High temperature
3 Defective water pump
4 Overcharge of refrigerant
5 Defective refrigerant circuit
6 Malfunction of linear expansion valve
stage-e
stage-f
-19 -18 -16 -15 -13 -12
-18 -17 -15 -14 -12 -11
stage-a stage-b stage-c stage-d stage-e stage-f stage-g
Model
W50,85 63
Tcond
HW112,140 63
1 Leakage or shortage of
2 Malfunction of linear
3 Refrigerant circuit is clogged
-TH3 < 0: and
63HS
w Clogging occurs in the parts
4 Disconnection of thermistor
1 Disconnection or contact
2 Defective pressure sensor
3 Defective outdoor controller
Case
· Clogged filter
· Leakage of water
· Low-load
· Inlet water is too cold.
(clogs)
valve
· Clogged filter
· Leakage of water
· Over-load
· Inlet water is too warm.
(clogs)
stage-b
stage-c
stage-d
-11 -10 -8 -7
-9 -8 -6 -5
Ambient temperature (TH7)
61 59 57 54 51
62 61 60 59 57
refrigerant
expansion valve
with foreign objects.
which become below freezing
point when water enters in
refrigerant circuit.
holder.
failure of connector (63HS)
on the outdoor controller
circuit board
circuit board
29
Judgment and action
<Cooling mode>
12 Check water piping.
3 Check water pump.
4 Check outdoor fan motor.
5~7 Check operating condition of refrigerant
circuit.
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-a
-3 -2 [W50,85]
-3 -2 [HW112,140]
[ ]
48
51
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.