38MGR-04SM Specifications subject to change without notice. 13
AUTOMATIC WIRING/PIPING CORRECTION
The unit is capable of automatically correcting a wiring/piping error. Indoor units do not have to be in the run mode. The outdoor temperature
should be above 41F (5C) to use this feature. Press the CHECK button on the outdoor unit PCB board for 6 seconds until the display shows
“CE” (“FA” may appear first – continue to press CHECK).
The outdoor unit takes control of the indoor units and adjust fan speed(s) according to the program. Setpoint display (if available) will be “76”
and outdoor unit will start the compressor and fan to dispense refrigerant to the indoor heads to determine piping setup versus physical wiring.
When the controller has adjusted control so that each indoor unit is synced to its piping port (approximately 5-10 minutes, depending on
temperature, unit size, etc.), “CE” is replaced with “00” on the display and the control program terminates.
NOTE: The indoor units will not automatically release from the “76” setting or return to previous control. Use the indoor
units’ remote controllers to restore them to normal function.
Fig. 13 — Automatic Wiring/Piping Correction
Indoor unit A
Indoor unit B
Indoor unit A
Indoor unit B
LED display
Check Switch
Terminal
block
Liquid/
Gas Pipe
B
A
B
A
Correct
Outdoor unit
Incorrect wiring
Terminal
block
B
A
Liquid/
Gas Pipe
B
A
Outdoor unit
Incorrect wiring
Terminal
block
B
A
Liquid/
Gas Pipe
B
A
Indoor unit A
Indoor unit B