Service Manual

OUTDOOR TECHNICAL OVERVIEW

B-4

ENGLISH

Components

1. A replaceable 25A 250V rated ceramic fuse protects the outdoor unit electronics. The fuse would open if a power surge or

internal short in the outdoor unit occurred. This fuse is eld replaceable.

2. The Power Circuit Board (PCB) receives line voltage from the building power supply via a connection between the Line

Power terminal on the outdoor unit and the terminals P1 and P2 of the PCB.

345. The voltage that powers the indoor units connects to terminals P3 and P4. The Electronic Control Unit receives power

to operate via connections at terminals P5 and P6. The Compressor Module board receives power via connections at

terminals P7 and TERMINAL 3.

When power is available to the Electronic Control Board and the Compressor Module board, their respective GREEN LED

indicators will be ashing if the unit is in standby, or continuously lit if the system is running. If the GREEN LED is not lit, there

may not be power to either the PCB or the board receiving power from the PCB. (The Power Control Board does not have a

power indicating LED.)

6. There is a communication plug labeled CN-1 on the PCB. This plug connects from the PCB to the Electronic Control Unit

(ECU). If this cable is disconnected or loose, the system will generate a Code 6 module low or high voltage error. This error

will not be displayed in memory on the indoor unit wired controller.

Power Circuit Board (PCB)

The purpose of the Power Circuit Board is to lter out potential electrical noise before it reaches the outdoor unit electronic

circuits. All voltage to operate the outdoor unit circuits must pass through the PCB.