Troubleshooting; Overview - Toshiba MMW-AP0271LQ-E Service Manual

8. TROUBLESHOOTING

8-1. Overview

(1) Before engaging in troubleshooting
(a) Applicable models
Super Module Multi (SMMS-i) models.
(Indoor units: MMW-APOOO, Outdoor units: MMY-MAPOOOO*)
(b) Tools and measuring devices required
• Screwdrivers (Philips, flat head), spanners, long-nose pliers, nipper, pin to push reset switch, etc.
• Multimeter, thermometer, pressure gauge, etc.
(c) Things to check prior to troubleshooting (behaviors listed below are normal)
NO.
1 A compressor would not start
2 A pump would not start
An outdoor fan would not start or would
3
change speed for no reason
4 A pump would not stop
The air conditioner would not respond to a
5
start / stop command from a remote controller
6 The water temperature dose not increase
(2) Troubleshooting procedure
When a fault occurs, proceed with troubleshooting in accordance with the procedure shown below.
Fault Investigate check code displayed
on interface P.C. board of header
unit
NOTE
Rather than a genuine fault (see the List of Check Codes below), the problem could have been caused by a
microprocessor malfunction attributable to a poor quality of the power source or an external noise. Check for
possible noise sources, and shield the remote controller wiring and signal wires as necessary.
Behavior
"E28" error
• Could it just be the 3-minute delay period (3 minutes after compressor
shutdown)?
• Could it just be the hot water module having gone thermo OFF ?
• Could it just be the hot water module put on the timer ?
• Could it just be the system going through initial communication ?
• Could it just be the outdoor unit under cooling operation ?
As the priority is usually given to operation of the indoor unit connected to
the same outdoor unit, the hot water module is in the waiting status
usually while the indoor unit works in cooling mode.
• Could it just be out of the water temperature using range ?
Hot water module is not possible to operat when water temperatue
above 60˚C
• Could it just be defrosting operation ?
• Could it just be defrosting or under oil (refrigerant) recovery control ?
• Could it just be the hot water module operation under external controller ?
• Could it just be the water flow rate is out of using range ?
Using renge of hot water module is rated ±15%
Investigate check code
displayed on interface P.C.
board of relevant follower unit
Any other fault
– 37 –
Possible cause
Check fault site or
faulty part