Pump Down Operation - Daikin VRV Inverter K Series Manual

SI-05C.BOOK Page 248 Monday, November 6, 2000 4:13 PM
Outline of Control

4.19 Pump Down Operation

When an outdoor unit is faulty, by fully closing both liquid and pressure equalizing valves and switching to
the service mode, you can conduct pump down operation (max. 1 hour) which purges refrigerant from the
faulty unit. When doing so, all indoor units are turned ON by thermostat. Refrigerant is discharged from the
low pressure line of the faulty unit by cooling with outdoor units that are not faulty up to low pressure
equivalent. Pump down operation is quit automatically after one hour. Just before quitting (when approx. 50
minutes elapse), shut the gas pipe's stop valve and then stop the outdoor unit. After another 10 minutes
passes, if the pressure in the outdoor unit doesn't exceed outdoor temperature equivalent pressure, the
process is complete.
4.19.1 Heat Pump System
Pump Down First fully close the liquid side and pressure equalizing side stop valves of the INV outdoor unit. The
Operation of INV execute low pressure control by setting indoor unit fan to L or off in accordance with the outdoor
Outdoor Unit temperature and No. 2 system outdoor unit suction pipe temperature.
Pump Down First fully close the liquid side and pressure equalizing side stop valves of the STD outdoor unit to be
Operation of STD
pumped down. The indoor unit fan is fixed at L tap.
Outdoor Unit
Normal cooling operation is executed by INV outdoor unit and STD outdoor unit 2 only.
Normal cooling operation is executed by INV outdoor unit and STD outdoor unit 1 only.
Outdoor unit operation is same as STD outdoor unit 1.
248
Step 1 : Operates No. 1 compressors only of STD outdoor unit 1 and 2.
Comp- Outdoor
ressor unit fan
INV outdoor
0 Hz + OFF H + ON
unit
STD outdoor
ON + OFF H + ON
unit 1
STD outdoor
ON + OFF H + ON
unit 2
l No. 2 outdoor unit liquid pipe temp.
l 5 minutes elapse
Step 2
: Operates all compressors of STD outdoor unit 1 and 2.
Comp- Outdoor
ressor unit fan
INV outdoor
0 Hz + OFF H + ON
unit
STD outdoor
ON + ON H + ON
unit 1
STD outdoor
ON + ON H + ON
unit 2
To pump down refrigerant of STD outdoor unit 1
Comp- Outdoor
ressor unit fan
INV outdoor
P I control H + ON
unit
STD outdoor
OFF H + ON
unit 1
STD outdoor
P I control H + ON
unit 2
To pump down refrigerant of STD outdoor unit 2:
Outdoor
Hot gas bypass
unit EEV
500 PLS ON
2000 PLS OFF
2000 PLS OFF
< 58 C
&
Outdoor
Hot gas bypass
unit EEV
500 PLS ON
2000 PLS OFF
2000 PLS OFF
Outdoor
Hot gas bypass
unit EEV
Low pressure
2000 PLS
protection control
500 PLS ON
Low pressure
2000 PLS
protection control
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SiE-05C
Indoor units execute
superheating control in this
mode.
STD outdoor unit 2 liquid
pipe temp. > 60˚C
(VF126)
Indoor units execute
superheating control in this
mode.
(VF170)
Functions PLUS Series