Toshiba MMU-AP0091H Troubleshooting Summary, Before troubleshooting, Troubleshooting procedure

9. TROUBLESHOOTING

9-1. Troubleshooting Summary

1.Before troubleshooting

1)Applied models

Super Heat Recovery Multi type models

(Indoor unit: MMX-APXXX, Outdoor unit: MMY-MAPXXXFT8)

2)Required tools / measuring devices

•Screwdrivers (Philips, Flat), spanner, longnose pliers, nipper, push pin for reset switch, etc.

•Digital multimeter, thermometer, pressure gauge, etc.

3)Confirmation before check (The following items are not troubles.)

No.	Operation	Check items
1	Compressor does not operate.	• Is it delayed for 3 minutes? (3 minutes after compressor-OFF)
		• Is thermostat OFF?
		• Is the fan operating or timer?
		• Is the system initially communicating?
		Heating operation cannot be performed under the condition that the outside
		temperature is 21°C or higher.
		Cooling operation cannot be performed under the condition that the outside
		temperature is –5°C or lower.
2	Indoor fan does not work.	• Is cold draft prevention control operating at heating mode?
3	Outdoor fan does not rotate, or	• Is it in low ambient cooling control?
	fan speed changes.	• Is a defrost operation being performed?
4	Indoor fan does not stop.	• Is the fan operating to remove residual heat after heating operation?
5	Start/stop operation on remote	• Is an auxiliary unit or remote controller being operated?
	controller is unavailable.
6	None	• Are the wire connections on the indoor units and remote controllers correct?

2.Troubleshooting procedure

When a fault has occurred, follow the procedure detailed below.

Trouble

Check the check display on the interface P.C. board of the header unit.

Check position or part in which trouble occurred.

NOTE) A malfunction of the microprocessor may be caused by power supply inconsistencies and external noise. If there are any noise sources, move remote controller and signal wires away from the noise sources or shield them.

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