Lack Of Refrigerant Or Discharging Pipe Blocked; 4-Way Valve Reversing Failure - Haier 2U18MS2VHB Service Manual

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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[16] Lack of refrigerant or discharging pipe blocked

Discharge & suction temperature Td-Ts≥80°C 10 minutes
after compressor start. Error status locks if it occurs 3 times
in 1 hour.
Possible causes:
• Wrong sensor connection
• Lack of refrigerant
• The senor is bad
• The 4-way valve is bad
• The electronic expansion valve is bad
• Out of the operating range

[17] 4-way valve reversing failure

Indoor pipe & indoor ambient temperature Tm-Tai≥5°C
10 minutes after compressor started. Error status locks
if it occurs 3 times in 1 hour.
Possible causes:
• The 4-way valve is bad
• The PCB is bad
• The 4-way valve coil connection is bad
• The system pressure difference is too small.
J-24
Flow Charts
Topic Title
Is the sensor wiring correct
and firmly connected?
Is the system leaking, or
Is the resistance of the
Td and the Tcm sensors
Use the unit according to
the allowable operating
Is connection between the
4-way valve and PCB is good?
Is the 4-way valve coil
wiring firmly in place and
characteristics correct?
Is the system meeting
4-way valve reversing
conditions (Pd-
Ps>0.6Mpa)?
Is 208/230VAC Measured on
PVB CN5 PCB after 4-way
valve reversing conditons are
Is there air noise after 4-way
valve reverses, and the temp.
of connection pipes on 4-way
valve normal?
TROUBLESHOOTING & REFERENCES
Yes
Yes
lacking refrigerant?
No
No
within range?
Yes
Is there an Internal
Yes
leakage in the 4-way
valve?
No
Is the electronic
Yes
expansion valve over
throttled?
range of the unit.
No
Yes
No
Yes
Yes
Yes
No
met?
Yes
No
No
Correct wiring
Repair leak and recharge
refrigerant
Replace the
sensor
Replace 4-way
valve
Adjust the valve opening
Reconnect
Correct wiring or replace
Check if the
compressor is running
Replace
PCB
Replace 4-way
valve

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