Toshiba Carrier MMD- AP0074BH2UL Service Manual page 29

Check function for operation of indoor unit (Functions at indoor unit side)
This function is provided to check the operation of the indoor unit singly without communication with the remote
controller or the outdoor unit. This function can be used regardless of operation or stop of the system.
However, if using this function for a long time, a trouble of the equipment may be caused. Limit using this
function within several minutes.
[How to operate]
1) Short-circuit CHK pin (CN71 on the indoor P.C. board).
The operation mode differs according to the indoor unit status in that time.
Normal time: Both float SW and fan motor are normal.
Abnormal time: Either one of float SW or fan motor is abnormal.
2) Restricted to the normal time, if short-circuiting DISP pin (CN72 on the indoor P.C. board) in addition to
short-circuit of CHK pin (CN71 on the indoor P.C. board), the minimum opening degree (30pls) can be
set to the indoor PMV only.
When open DISP pin, the maximum opening degree (1500pls) can be obtained again.
[How to clear]
Open CHK pin. While the system is operating, it stops once but automatically returns to operation after
several minutes.
DISP pin open(CN71)
Fan motor
Indoor PMV (∗) Max. opening degree (1500pls)
Drain pump
Communication
P.C. board LED
Short-circuit of CHK pin(CN71)
Normal time
DISP pin short circuit(CN71)
(H)
Min. opening degree (30pls)
ON
All ignored
Lights
– 29 –
(H)
Min. opening degree (30pls)
ON
All ignored
Lights
Abnormal time
Stop
ON
All ignored
Flashes