19
Refrigerant migration during the off cycle can result in a noisy start up. Add a crankcase
heater to minimize refrigeration migration, and to help eliminate any start up noise or
bearing “wash out”.
All heaters must be located on the lower half of the compressor shell. Its purpose is to
drive refrigerant from the compressor shell during long off cycles, thus preventing
damage to the compressor during start-up.
The crankcase heating start condition:
1.The crankcase heating start must meet two conditions:
A. Outdoor temperature
<
37.4° F.
B. Compressor stops working more than 3 hours.
2. Outdoor temperature
<
37.4° F and just connected to the power source.
The crankcase heating stop must meet condition:
Outdoor temperature
>
44.6° F or compressor start.
At initial start-up or after extended shutdown periods, make sure the heater is energized
for at least 12 hours before the compressor is started. (Disconnect switch on and wall
thermostat off.)
2
、
Crankcase heating zone description
●
Dial code SW5
:
Defrosting quit
According to outdoor coil temp.T3 is up to 18
℃
and lasts for 1 min. Or defrosting time
is up to 8 min.
●
Defrosting control choice
Dial code SW5 can adjust and set the time that enters and quits defrosting
In general, adjust dial code to ON can enhance the ability of defrosting.
●
Manual defrosting:
The system must operate in heating mode.
Enter into this mode after 5 min when system starts(It is suggest that stably running for
30 min, then enter )
Press Force button and hold for at least 6s to enter into defrosting.
It is suggest that manual defrost time interval is 15min above.
●
Start if crankcase heating zone can satisfy one of the 3 conditions,
1. First time to power on
2. In process of defrosting
3
.
Compressor stops running for 4h and the outdoor ambient temp. T4 once lower than
50
℉
.
Stop crankcase heating zone satisfy the following conditions
Air discharge temp. T5
≥
113
℉
●
Defrosting enter
The following 3 situations were determined to enter into defrosting:
①
Outdoor coil temp.
T3
<
1
℃
, and satisfy a certain correspondence of T4 ambient temp.
②
When operating time accumulates to a certain value. Because of ambient temp. T4
time settings are different, when T4<-5
℃
, cumulative time is 4h, when T4
≥
-5
℃
and T4
<
4
℃
, the cumulative time is 2h to determine.
③
When high pressure lasts low, the
situation that high pressure saturation temperature lower than 28
℃
lasts for 20 min
determines to enter into defrosting.
Defrosting choice
SW5-1
SW5-2
Remarks
ON
Operating time
shorten q0%
Defrosting time is
becoming longer
OFF
Normal
Normal
Default OFF
Remarks
Enter into the
situation
Quit situation
ON
OFF
1 2
8.1 COMPRESSOR CRANKCASE HEATER (CCH) (Heat pump only,
optional
)