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SW5
Defrost Options
Manual Defrost (Heat Pump Only)
1. Demand defrost can start when the system has been
2. Press "Force" key during 6 seconds to initiate demand defrost.
3. Wait approximately 40 seconds to watch the initiation of the defrost cycle.
4. Once defrost cycle has started, the display will show "DF" .
5. Defrost test ends automatically and the display will show speed of operation.
6. If a second test is required, repeat Step 3 after 5 minutes has elapsed.
Compressor Crankcase Heater Description
The migration during the OFF cycle can result in a noisy startup. The use of a crankcase heater
(CCH) minimizes refrigerant migration, reduces startup noise, and reduces the wearing out of
bearings.
Crankcase heater must be located on the lower half of the compressor shell. Its purpose is to heat
the compressor during the OFF cycle and avoid the return of refrigerant to the compressor.
At initial startup, or after extended periods of inactivity, the crankcase heater must be activated
during a minimum of 12 hours prior to compressor operation, applying line tension to the system
but with the controller in OFF mode.
Crankcase heater operation is initiated:
1. When the application of line tension for the first time and compressor discharge temperature
2. During the defrost process.
3. When compressor stops operating during a period of 4 hours and outdoor temperature is
Crankcase heater operation ends:
1. When compressor discharge temperature is T5 ≥ 113ºF.
2. During heating mode and stops working during cooling mode.
MS-SVN052E-EN
ON
OFF
1
2
SW5-1
Operating time
ON
is reduced by
10%
OFF
Normal
Remarks
Enter defrost
operating in heating mode during a period exceeding 8 minutes.
is T5˂104ºF.
T4˂50ºF or T5˂104ºF.
SW5-2
Remarks
Defrost
extended by 60
seconds
Normal
Default
Cancel defrost
System Operation
21
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