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Daikin VRV III-S RXYMQ36 48PVJU Service Manual: Defrosting Operation

60 hz.
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SiUS34-907
3.3

Defrosting Operation

The defrost operation is performed to solve frost on the outdoor unit heat exchanger when heating, and the
heating capacity is recovered.
[Conditions to start]
The defrost operation is started referring following conditions.
 Outdoor heat exchanger heat transfer co-efficiency
 Temperature of heat-exchange (Tb)
 Timer (2 hours at the minimum)
In addition, outdoor heat-exchange co-efficiency is derived from Tc, Te, and the compressor load.
Outdoor unit actuator
Compressor
Outdoor unit fan
Four-way valve (Y1S)
Main electronic expansion valve (EV1) SH control
Subcooling electronic expansion valve
(EV3)
Hot gas bypass valve (SVP)
Ending conditions
* From the preparing operation to the defrost operation, and from the defrost operation to the operation after
defrost, the compressor stops for 1 minute to reduce noise on changing of the four-way valve.
Fan
Electronic expansion valve
Function
Defrost preparation
operation
Upper limit control
STEP 8
ON
0 pls
OFF
2 min.
Indoor unit actuator
Thermostat ON unit
Stopping unit
Thermostat OFF unit
Thermostat ON unit
Stopping unit
Thermostat OFF unit
Defrost operation
140 Hz Full load
OFF
OFF
480 pls
0 pls
ON
• 15 min.
or
• Tb>4°F
{
&
• Ts1 - Te<52°F
Heating oil return operation
Special Control
Post Defrost operation
2-step increase from
36 Hz Unload to
(Pc - Pe>58 psi)
every 20 sec.
STEP 8
ON
55 pls
0 pls
ON
• 160 sec.
or
• Pc - Pe>58 psi
OFF
OFF
OFF
416 pls
256 pls
416 pls
39

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  • cp shukla Feb 16, 2016 06:50:
    RXYQ18PAY6 service manual & vrv Fulform