Fixed Fan-Output; Function Of Switches On The Outdoor Controller Board; Operation During The Power-On-Reset State; Time Shortening - Mitsubishi PU12EK Technical & Service Manual

6. Fixed fan-output

While the compressor is operating and the fan output step is indicated by LED, pushing SW2 fixes the fan output of that time.
The fixed fan-output can be released when either of the following conditions is satisfied.
1 SW2 is pushed again.
2 SW3 setting is changed.
3 The compressor stops.

7. Function of switches on the outdoor controller board

SW1 : Clears the check code memory (push-button switch)
SW2 : Switches the output state indication and the check code display (push-button switch)
SW3-1and3- 2 : Switches the output state indication items (dip-switch)
For further information, please refer to page 21.

8. Operation during the power-on-reset state

(1) When the circuit breaker is turned to ON, the microprocessor enters the power-on-reset state, which continues until the
direct current for the microprocessor control reaches 12V.
Then the microprocessor starts operation in the following order.
1 Each I/O port clearance
2 Function input
Function depends on jumper wires set beforehand in the factory.
Jumper wire
J1 Reversed phase sensor
J2 Not applied for series PU
J3 Crankcase heater control
Target temperature of outdoor
J4
coil temperature
3 Check for a reversed phase
4 Check for an open phase (with J1)
5 50/60Hz judgment
6 EEPROM data loading (check mode, and total time of compressor operation)
7 Coil temperature initial input
(2) If an open phase or a reversed phase is sensed, LED blinks every other second.
NOTE
If power is not supplied to the transformer and the microprocessor, the microprocessor does not work and can sense nei-
ther a reversed phase nor an open phase.
If a contact point of protective device such as the high pressure switch has already been opened in the power-on-reset
state, it is regarded as an open phase.
In this case, all LED are OFF.
9. 100% fan output
Fan output is fixed to 255 (100%) by shorting CN22. However, the fan stops during compressor OFF or defrosting operation.
Open circuit of CN22 enables the fan control to start.

10. Time shortening

Short circuit of CN21 shortens the time listed below.
1) Fan control period : 30 sec.
2) Three-minute time delay function : 3 min.
3) Compressor ON/OFF time for bypass valve ON/OFF : 30 min.
4) Compressor ON time to start other functions : x min.
Function
Sensed
Refer to 5 (1) on page 19.
86˚F
For heat pump units
3 sec.
3 sec.
x sec.
With jumper wire
30 sec.
20
Without jumper wire
Not sensed
Refer to 5 (2) on page 19.
95˚F
For cooling unit