![](/images/new-backgrounds/1131911/131911399x1.webp)
4
4. Service procedures
(12) Checking procedure for each PC Board
The indoor and outdoor PCBs have functions to check the signal transmission and reception of the serial circuit and to check the microcomputer operation.
●Precautions required when checking
1.After turning off the power to the indoor (outdoor) unit, remove the
2.Short the CHECK PIN on the PC board of the indoor (outdoor) unit and turn on the power.
3.When checking the Outdoor controller, remove the compressor wiring from the compressor electromagnetic contactor.
Indoor controller: A lighted LED indicates normal. A blinking LED indicates abnormal.
Outdoor controller: Blinking LEDs (D11 and D22) indicate normal. If one of the LEDs (D11 and D22) goes off, it indicates abnormal.
When the microcomputer works normally, the relays are switched in sequence as below.
Indoor controller
|
|
| Output | ON time | ||||
|
|
|
|
|
|
|
|
|
|
| Indoor fan | Very high fan speed (HH) | 0.5 seconds | ||||
|
|
|
|
|
|
|
|
|
|
| Indoor fan | High fan speed (H) | 0.5 seconds | ||||
|
|
|
|
|
|
|
|
|
|
| Indoor fan | Low fan speed (L) | 0.5 seconds | ||||
|
|
|
|
|
|
|
|
|
|
| Indoor fan | Very low fan speed (LL) | 0.5 seconds | ||||
|
|
|
|
|
|
|
|
|
|
| Flap motor |
|
|
|
|
| 0.5 seconds |
|
|
|
|
|
|
|
|
|
|
| Drain pump |
|
|
|
|
| 0.5 seconds |
|
|
|
|
|
|
|
| |
Operation order | Electric heater | 0.5 seconds | ||||||
|
|
|
|
|
|
|
| |
|
| Operation signal | 0.5 seconds | |||||
|
|
|
|
|
|
|
|
|
|
| In a lump |
|
|
|
|
| 0.5 seconds |
|
|
|
|
|
|
|
| |
|
| Electronic control valve A | 0.5 seconds | |||||
|
|
|
|
|
|
|
| |
|
| Electronic control valve B | 0.5 seconds | |||||
|
|
|
|
|
|
|
| |
|
|
|
|
|
| |||
|
| Electronic control valve.A |
|
|
| 0.5 seconds | ||
|
|
|
|
|
|
|
| |
|
|
|
| |||||
|
| Electronic control valve | B |
| 0.5 seconds | |||
|
|
|
|
|
|
|
| |
|
| Outdoor controller |
| |||||
|
|
|
|
|
|
|
|
|
|
|
| Output | ON time | ||||
|
|
|
|
|
|
|
|
|
|
| Outdoor fan | High fan speed (H) | 0.5 seconds | ||||
|
|
|
|
|
|
|
|
|
Operation order |
| Outdoor fan | Low fan speed (L) | 0.5 seconds | ||||
|
|
|
|
|
|
|
| |
|
|
|
|
| 0.5 seconds | |||
|
|
|
|
|
|
| ||
|
|
|
|
|
|
|
| |
|
| Compressor | 0.5 seconds | |||||
|
|
|
|
|
|
|
|
|
SM830082
IV - 44