Before Troubleshooting; Troubleshooting Procedure - Toshiba MCY-MHP0404HT-C Service Manual

9-1-1. Before Troubleshooting

Australian demand response model A1 series corresponds to DRED (Demand response enabling device) by
AS/NZS 4755.3.1.
DRM1 are executed as follows, upon directions from the power company.
Be sure to confirm they are not operated before usually troubleshooting.
Air conditioner demand response
Demand response mode
DRM1
D R M 2
DRM3

9-1-2. Troubleshooting Procedure

When a symptom such as the following table is found without a check code is not displayed on the remote
controller, there is a possibility that a demand operation or demand P.C. board is failed, therefore diagnose it
according to the following diagram.
Operating conditions of air conditioner
Each condition is within the operating condition,
but the compressor does not work.
Diagnosis when compressor does not work
Disconnect the
connecting wiring
of DRED.
Compressor works.
NO
LED of the demand
P.C. board is on.
YES
Remove wiring of
CN106 on DRED
P.C. board.
Compressor works.
YES
Exchange of
Demand P.C. board
Description
Compressor off
N t o a a v a l i b e l
Not available
Normal
YES
(Demand operation)
or DRED is failed.
Demand
NO
P.C. board is failed.
∗
Refer to next page
Indoor unit
NO
satisfies ON conditions
of the compressor.
NO
Indoor thermostat
is off.
95
YES
Inverter Assy
is failed *1
When a failure with *1 appears,
advance the diagnosis further according
to the basic service manual.