[ VII Control ]
- 85 -
HWE1018A GB
-7- Defrost Operation Control
(1) Starting the defrost operation
The defrost cycle starts when the pipe temperature (TH3) at or below the value in the table below has continuously been de-
tected for three minutes after the cumulative compressor operation time of 50 minutes have passed (90 minutes when the
defrost prohibit timer is set to 90 minutes.).
If 10 minutes have passed since compressor start-up or since the completion of defrost operation, forced defrost operation
will start by turning on the forced defrost switch (DIP SW2-7).
Even if the defrost prohibit timer is set to 90 minutes, the actual defrost prohibit time for the next operation will be 50 minutes
if defrosting took 12 minutes.
In the multiple-outdoor-unit system, all of the outdoor units that are in operation go into the defrost mode simultaneously. The
unit(s) that is stopped at the time defrost operation starts remains stopped.
(2) Defrost operation
(3) Stopping the defrost operation
The defrost cycle ends when 12 minutes have passed since the beginning of the cycle, or when the pipe temperature (TH3),
in the following table, or above has been continuously detected for 4 minutes (when SW3-4 is set to OFF) or 2 minutes (when
SW3-4 is set to ON) that exceeds the values in the table below.
The defrost cycle will not end for two minutes once started unless one of the following conditions is met : Pipe temperature
reaches 25°C [77°F] and SW3-4 is set to OFF OR
*1
=25°C+TH7°C [77°F+TH7°F] and SW3-4 is set to ON.
*1 5°C [41°F] 25°C [77°F]
In the multiple system, defrosting is stopped on all units at the same time.
(4) Problems during defrost operation
If a problem is detected during defrost operation, the operation will be stopped, and the defrost prohibition time based on the
integrated compressor operation time will be set to 20 minutes.
Model
TH3
SW3 - 3 OFF SW3 - 3 ON
250 model - 10°C [14°F] - 5°C [23°F]
Compressor frequency Model Compressor frequency
250 model 65 Hz
Outdoor unit fan Stopped
SV1a ON
SV5b OFF (open)
21S4a OFF
21S4b OFF
SV9 OFF
LEV1 0 pulse
*1
*1. This value may be greater than 0 pulse depending on the 63LS and TH4 status.
LEV2 3000 pulses
Model
TH3
SW3 - 4 OFF SW3 - 4 ON
250 model 10°C [50°F] 5°C [41°F]
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