Troubleshooting Procedure; Diagnosis When Compressor Does Not Work; Diagnosis When Cooling/Heating Is Poor - Toshiba RAS-4M27S3AV-E Service Manual

11-6. TROUBLESHOOTING
RAS-4M27S3AV-A
1. Before Troubleshooting
Each model corresponds to DRED (Demand response enabling device) by AS/NZS 4755.3.1.
DRM1, DRM2 and DRM3 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
DRM2
DRM3
*1: E30m = total electrical energy (kWh) used by the all conditioner for all purposes (including compressors,
controls and fans) over a 30 min period.
*2: R = rated input electrical power of the air conditioner (kW) at rated capacity in the mode in which it is
operating during the demand response event (i.e. cooling or heating).

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.
No. Operating conditions of air conditioner
Each condition is within the operating condition,
1
but the compressor does not work.
2 Cooling/Heating of the room is poor

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
CN105 on DRED
P.C. board.
Compressor works.
YES
Exchange of
Demand P.C. board
Description
Compressor off
E30m ≤ R × 0.50 × 0.5
E30m ≤ R × 0.75 × 0.5
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.

Diagnosis when cooling/heating is poor

Disconnect the
connecting wiring
of DRED.
Cooling/heating
improved.
NO
Abnormal cycle
system, etc. *1
YES
Inverter Ass'y
is failed *1
When a failure with *1 appears,
advance the diagnosis further according
to the basic service manual.
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FILE NO. SVM-15073
Normal
YES
(Demand operation)
or DRED is failed.