Haier HSU-18,22HVA103/R2(DB) Service Manual page 30

Among which: C:TA＜0℃，C=0.8
For area prone to frost, the value is set at 6 when unit leaves the factory.
Defrosting entry temperature control -15 ≤C×TA
Defrosting Time Interval
time interval between two defrosting cycles is 45 minutes.
Defrosting Operation
When defrosting begins, compressor will stop for one minute, external fan is running and 50s later,
four-way valve will be off.
When compressor starts, external fan will be off, compressor will run at 60Hz for 60s then move on to
target frequency of 80Hz.
During defrosting, compressor current and air discharge overheat protection features are effective.
During defrosting, if compressor shuts down due to activation of protection feature or due to
malfunction, it will resume after 3 minutes. In the unit is still within defrosting cycle, it will resume
defrosting and startup of compressor will be based on the rule for defrosting startup. (The unit will exit
defrosting mode and handle fault in the event of 3 consecutive restart failures.)
On entering defrosting, it must guarantee that compressor will operate for a minimum of 2 minutes in
defrosting mode before exit.
Defrosting Exit Condition
When one of the following conditions is met, defrosting operation will be switched to heating
operation.
（1）:Temperature of outdoor heat exchanger exceeds 7
（2）: Temperature of outdoor heat exchanger exceeds 12
（3）:Defrosting operation continues for 9 minutes.
When defrosting exit conditions are met, the unit will operate as follows
Compressor stops and external fan starts, 50s later, four-way valve will be on, 60s later, compressor
will operate as per startup process.
5.2.5 PTC Output Control
When outdoor unit is energized, PTC output value is 0, 10s later, output value is 1.
When compressor stops for 10 minutes continuously, PTC output value is 0.
On receiving compressor startup instruction, initial PTC output is 1, and compressor startup will be
performed 5s later.
5.2.6 System Protection Function
5.2.6.1 3 minutes stand-by time
Time interval between compressor shutdown and restart is set at 3 minutes to ensure that compressor
will only restart after 3-minute shutdown and initial energization valves are turned on to adequate
18 2 HVA103/R2(DB)
TA≥0℃，C=0.6
℃ －α≤-5℃
for 80s continuously
℃
℃ for 5s continuously
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