Mitsubishi Electric PUHZ-W50VHA-BS Service Manual page 51

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 min-
utes.
<Heating mode> (HW112,140V/YHA2)
Abnormal if inlet water temperature ther-
mistor (TH32) is 15: or lower, and the
following condition (1 or 2) are detected.
1. 1 minute has passed since defrost-
ing operation started and plate heat
exchanger pipe temperature thermistor
(TH6) stays at -6: or lower for con-
tinuously 30 seconds.
2. During defrosting operation and plate
heat exchanger pipe temperature ther-
mistor (TH6) stays at -16: or lower
for continuously 10 seconds.
P6
(2) Overheating protection <Heating mode>
Abnormal if condensing temperature of
pressure sensor (63HS) detects
Tcond. : or more and compressor
operation frequency is less than or equal
to 30 Hz. Detection is inoperative during
defrosting.
Tcond
stage-g
Tcond
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
-TH32 [ 2: and
T
P8
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.
Detection is inoperative for 3 minutes after
UE
compressor starting and 3 minutes after
and during defrosting.
OCH439H
(1) Freezing protection
1 Reduced water flow
2 Low temperature
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
2 Low temperature
3 Defective water pump
4 Leakage or shortage of refrigerant
5 Malfunction of linear expansion valve
(2) Overheating protection
1 Reduced water flow
2 High temperature
3 Defective water pump
4 Overcharge of refrigerant
5 Defective refrigerant circuit (clogs)
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
HW112,140V/YHA(2) 63
61
HW140VHA2R1-BS
1 Leakage or shortage of
2 Malfunction of linear expansion
-TH3 < 0: and
63HS
3 Refrigerant circuit is clogged
w Clogging occurs in the parts
4 Disconnection of thermistor
1 Disconnection or contact failure
2 Defective pressure sensor
3 Defective outdoor controller
Case
<Cooling mode>
· Clogged filter
· Leakage of water
· Low-load
· Inlet water is too cold.
· Clogged filter
· Leakage of water
· Low-load
· Inlet water is cold.
<Heating mode>
· Clogged filter
· Leakage of water
· Over-load
· Inlet water is too warm.
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
62 61 60 59 57
refrigerant
valve
with foreign objects.
which become below freezing
point when water enters in
refrigerant circuit.
holder.
of connector (63HS) on the
outdoor controller circuit board
circuit board
51
Judgment and action
(1) Freezing protection
<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.
4 Correct to proper amount of refrigerant.
5 Check linear expansion valve. Refer to 8-5.
(2) Overheating protection
<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 [W50,85VHA(R1)]
-3 -2 [HW112,140V/YHA(2)]
[ ]
48
51
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 9-7.)
3 Replace outdoor controller board.