M thermal Mono
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202008
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Procedure
4.16.4
P1
High pressure switch connection or
pressure sensor connection on outdoor
unit main PCB is loose
1
Yes
Ensure the pressure switch is connected
properly
No
Pressure sensor has short-circuited or
failed
2
Yes
Replace the pressure sensor
No
The high pressure side is blocked, caused
by crushed or bent pipe or blocked EXV
3
Yes
Inspect the system and fix the error
No
The heat exchange is poor
4
Yes
Inspect the system and fix the error
No
The water flow rate is not sufficient in
cooling mode
5
Yes
Inspect the water system and fix the
error
No
Replace outdoor main PCB
Notes:
1.
High pressure switch connection is port CN31 on the outdoor unit refrigerant system main PCB (labeled 21 in Figure 4-2.2).
2.
Measure the resistance among the three terminals of the pressure sensor. If the resistance is of the order of mega Ohms or infinite, the pressure sensor
has failed.
3.
High pressure side blockage causes discharge temperature to be higher than normal, discharge pressure to be higher than normal and suction pressure to
be lower than normal.
4.
In heating mode check water side heat exchanger, water piping, circulator pumps and water flow switch for dirt/blockages. In cooling mode check air side
heat exchanger, fan(s) and air outlets for dirt/blockages.
5.
Check water pressure on the manometer. If the water pressure is not > 1 bar, water flow is insufficient. Refer to Figure 2-1.1.
Midea CAC Confidential
