29
NOTE : Opening increases and decreases to be in the target discharge temperature during operation.
Opening
completely
Positioning
Power ON
Initial opening
Standard opening
Remote
controller
ON
➔
Operation
Thermostat
OFF
Standard opening
Thermostat
ON
Opening in stop
Operation
Opening in stop
Remote
controller
OFF
Opening
completely
Remote
controller
ON
➔
Positioning
Standard opening
Operation
Time
LEV opening
Initial opening
Initial opening
Open
Close
(2) LEV time chart
SERVICE FUNCTIONS
10
10-1. COMPULSORY DEFROSTING MODE FOR SERVICE
By short circuit of the connector JPDS and JPSG(MUH-A18WV)/ JPG1 and R871(MUH-A24/A30WV) on the outdoor deicer
P.C. board, defrosting mode can be accomplished regardless of the defrost interval restriction. (Refer to page 37 or 38.)
Defrost thermistor RT61 must read below -3°C.
10-2. CHANGE IN DEFROST SETTING
<JRF> When the JRF wire of the deicer P.C. board is cut, the defrost interval time will be changed.
<JRG> When the JRG wire of the deicer P.C. board is cut, the defrost temperature will be changed.
(Refer to page 37 or 38.)
E1
Jumper wire
JRF
JRG
Model
Change point
Defrost interval time changes from 40 minutes to 15 minutes.
Defrost start temperature changes from -3
:
to 0
:
. (MUH-A18WV)
Defrost start temperature does not change.(-3.0
:
)(MUH-A24/A30WV)
Defrost finish temperature changes from 3
:
to 10
:
.(MUH-A18WV)
Defrost finish temperature changes from 3
:
to 15
:
.(MUH-A24WV)
Defrost finish temperature changes from 13
:
to 15
:
.(MUH-A30WV)
E1
E1
MUH-A18WV -
MUH-A24WV -
MUH-A30WV -
MUH-A18WV -
MUH-A24WV -
MUH-A30WV -
E1
E1
E1
TROUBLESHOOTING
11
11-1. Cautions on troubleshooting
1. Before troubleshooting, check the following:
(1) Check the power supply voltage.
(2) Check the indoor/outdoor connecting wire for mis-wiring.
2. Take care the following during servicing.
(1) Before servicing the air conditioner, be sure to first turn off the remote controller to stop the main unit, and then after
confirming the horizontal vane is closed, turn off the breaker and / or disconnect the power plug.
(2) Be sure to turn OFF the power supply before removing the front panel, the
cabinet, the top panel, and the electronic control P.C. board.
(3) When removing the electronic control P.C. board, hold the edge of the
board with care NOT to apply stress on the components.
(4) When connecting or disconnecting the connectors, hold the housing of the
connector. DO NOT pull the lead wires.
MUH-A18WV -
MUH-A24WV -
MUH-A30WV -
E1
E1
E1
3. Troubleshooting procedure
(1) First, check if the OPERATION INDICATOR lamp on the indoor unit is flashing on and off to indicate an abnormality.
To make sure, check how many times the abnormality indication is flashing on and off before starting service work.
(2) Before servicing check that the connector and terminal are connected properly.
(3) If the electronic control P.C. board is supposed to be defective, check the copper foil pattern for disconnection and the
components for bursting and discolouration.
(4) When troubleshooting, refer to the flow chart on page 30.
Lead wiring
Housing point
OB322-1.qxp 03.11.13 4:06 PM Page 29
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