Haier MVAB009MV2AA Service Manual page 40

[18] The 4-way valve of 3-pipe valve box reversing failure
If the 4-way valve of 3-pipe
valve box is internal leakage
Check if the TC1 and TC2 of indoor
unit are normal, if the resistance is
right? If the connect well?
If the 4-way valve of outdoor
unit is internal leakage
Replace the driver module, if it is normal
If exceeds the running range of the
Adjusting the running range
Note: abnormity confirmation conditions
For MRVIII-RC system, the outdoor unit is running normally, when the 4-way valve of valve box is
power on and its connected heating indoor unit's parameter satisfy following conditions
• & • When 4-way valve of valve box is ON
• TC2 ≤ CT-20
• or
No
Yes
Yes
No
outdoor unit
Yes
o
C lasts for 5min
o
• TC1 ≤ 0 C lasts for 5min
• TC1 ≤ master unit Ps_temp+10
Adjust it correctly by after-sales
Yes
personnel on site.
No Adjust it correctly by after-sales
personnel on site.
No
Adjust it correctly by after-sales
personnel on site.
Yes
Replace the driver module
If the pressure difference between
high and low pressure less than
No
0.4Mpa before the failure occurs,
replace the inverter compressor
o
C lasts for 5min
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