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Haier 2U18MS2VHB Service Manual page 86

Ductless multi-split heat pump, outdoor/indoor, wall mount - highwall, 2'x2' compact cassette, 3'x3' large cassette, slim duct, mid-static ducted, medium static ducted, console
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Testing Communication Circuit
If an Error E7 occurs, perform the following test to determine
if the indoor control board is functioning properly to send data
to the outdoor unit.
Perform this test with the unit powered and all wiring
connected between indoor and outdoor unit.
Make sure all wiring between the indoor and outdoor unit
are correct. There should no splices between the indoor and
outdoor unit wiring connecting terminals 1 or 3. Make sure
wiring is correct, before performing this test.
1. Measure the DC voltage between terminals 1 and 3 on the
indoor terminal block.
2. The voltage should fluctuate between 8VDC and 23VDC.
The fluctuating signal indicates a good communication
path.
3. If the voltage does not fluctuate, and the wiring is good,
the indoor board is defective.
G-8
Testing
MID-STATIC DUCTED TECHNICAL OVERVIEW
Indoor Fan Motor Voltage Check
If The Indoor Fan Motor Does Not Run:
1. Remove the front cover and access the fan motor circuit
board connection.
2. Reset power and turn the remote control fan command to
Fan On mode.
Motor Test:
1. If the motor doesn't run, check for 310VDC between Pins 1
and 3. If it is not present, the indoor board is bad. If voltage
is present, continue on.
2. Check the voltage between Pins 3 and 4. The voltage
should be +15VDC. If it is not present, the board is bad. If
voltage is present, continue on.
3. Check for voltage between Pins 3 and 6. If no DC voltage is
present, the board is bad. If voltage is present, change the
motor.
1
3
Red
Black
White
DC Motor
Yellow
Blue
2
+310 VDC
DC Ground
+15 VDC
Signal
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