Fujitsu AirStage AB12, Service Manual

Page: 49 / 199

Four-way valve 1 (4WV1) operates for "Cooling/heating selection" type only.
1. 4-way valve delayed switching
When the outdoor operation mode is Stop, 4-way valve 1 maintains its state and turns off 2 minutes 35 seconds later.
However, when the outdoor unit operation mode is switched from " Heating " to " Cooling ", this function
does not operate and the 4-way valve turns off at that point.
When the compressor satisfies the OFF ON condition when the operation mode is "Heating" (including immediately
after the power is turned on), 4-way valve 1 turns off for 5 seconds. Thereafter, 4-way valve 1 turns on and 3 seconds
later, the compressor starts.
However, except in the following cases:
Defrosting, defrosting end
Oil recovery in progress, oil recovery end
2. Restarting 4-way valve switching
Four-wave valve 1 is set according to the operation modes as shown below.
*1) 4-way valve 1 delayed switching control compatible
3. 4-way valve 1 setting by operation mode
ON
OFF
ON
OFF
Compressor
4-way valve 1
ON
OFF
Outdoor Fan
Operation example (Restarting 4-way valve switching)
3 mins ST 3 secs 5 secs
Compressor ON condition
4-way valve 1 control by operation mode
Cooling / Heating
selection type
Operation mode System type 4WV1
Cooling
Heating
Stop
OFF
ON
OFF*
5-5 FOUR-WAY VALVE 1 CONTROL
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