Operation Details - Fujitsu WPYA100LA Service Manual

DEFROSTING OPERATION(FOR A UNIT HEAT EXCHANGER)
• Defrosting operation is controlled by the temperature of outdoor heat exchanger sensed by the thermistor and
the timer switch.
• Defrosting operation starts when the both of the following conditions are met at the same time.
a)35 minutes' of continuous run of the compressor after the start of heating operation or after the completion of
previous defrosting operation.
b)The temperature of the outdoor heat exchanger stays lower than -1.5°C continuously for two minutes.
• Defrosting operating is called off if either of the following conditions is met.
a)The temperature of outdoor heat exchanger rises to 19°C while 4-way-valve is ON.
b)12 minutes has passed since compressor turned ON.
Temperature of
outdoor heat exchanger
-1.5˚C
Compressor
Outdoor fan
4way valve
• Working condition of frost protection heater for expansion vessel
The heater turns ON if the outdoor temperature keeps below 3 degree for 1 minute.
The heater turns OFF if the outdoor temperature keeps above 5 degree for 1 minute.
Defrosting starts
19˚C
2min.
ON OFF
ON
10
sec.
50sec.
53sec.

OPERATION DETAILS

MAX 90Hz
ON
Max 12min.
– 5 –
Defrosting stop
OFF ON
ON
50sec.
53sec.