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Climate Class 6100i / 6000i / 8100i / 8000i
2. Caution in checking printed circuit boards (PWB)
2.1. Non-insulated control circuit
The GND terminals of the low-voltage circuits (control circuits for microcomputer and thermistors and drive circuits for expansion valve and relays) on
the control printed circuit board (PWB) are connected to the compressor drive power supply (320-VDC negative terminal). Therefore, exercise utmost
caution to prevent electric shock.
If a measuring instrument used for the test is grounded, its chassis (ground) has the same electric potential as the 0-V probe. Since non-insulated cir-
cuits have the following voltage potential difference from the ground, connection of the grounding wire results in a short-circuit between the 0-V line and
the ground, thus allowing an excessive current to ow to the tester to cause damage.
If the sheaths of the thermistor lead wires or expansion valve lead wires inside the outdoor unit become damaged due to pinching by the front panel or
other metal parts or contacting a pipe, a high voltage can ow and destroy the circuits. To prevent these problems, carefully conduct assembly work.
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