Special Control; Startup Control - Daikin FCQ18PVJU Service Manual

Special Control

3. Special Control
3.1

Startup Control

On activation, the following control is performed to lighten the load of the compressor with liquid
refrigerant located at the compressor at startup. Also, the position of the four-way valve is
defined.
3.1.1 Startup Control in Cooling Operation
Actuator
Compressor
Outdoor unit fan
Four-way valve
Main electronic expansion valve (EV1)
Subcooling electronic expansion valve
(EV2)
Hot gas bypass valve (SVP)
Receiver gas discharging valve (SVG)
Ending conditions
3.1.2 Startup Control in Heating Operation
Actuator
Compressor
Outdoor unit fan
Four-way valve
Main electronic expansion valve (EV1)
Subcooling electronic expansion valve
(EV2)
Hot gas bypass valve (SVP)
Receiver gas discharging valve (SVG)
Ending conditions
21
Operation
Differential pressure control
High pressure control
OFF
1400 pls
0 pls
ON
OFF
• 230 sec.
• Pc - Pe>58 psi
or
(
&
• 45 sec.
Operation
Differential pressure control
STEP 8
ON
180 pls
0 pls
ON
OFF
• 145 sec.
• Pc - Pe>58 psi
or
(
&
• 15 sec.
SiUS28-902_a
Remarks
Compressor operating frequency
increases by 2 step / 20 sec. until
Pc - Pe>58 psi.
Initial fan speed is set to STEP 0.
1-step increase with Pc>305 psi
1-step decrease with Pc<261 psi
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Remarks
Compressor operating frequency
increases by 2 step / 20 sec. until
Pc - Pe>58 psi
⎯
⎯
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⎯
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Function