Defrosting Operation - Daikin SkyAir RZR-P Series Service Manual

SiUS281117
3.3

Defrosting Operation

Pc: High-pressure sensor detection value
Pe: Low-pressure sensor detection value
Tc: High-pressure equivalent saturation temperature
Te: Suction pipe equivalent saturation temperature
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 unit heat exchanger heat transfer co-efficiency
 Temperature of heat exchanger (Tb)
 Timer (2 hours at the minimum)
Parts Name Symbol
RZR18/24/32P
RZQ18/24/30P
Compressor

M1C
(INV.)
Outdoor unit

M1F
fan
Four-way
20S1 Y1S
valve
Electronic
expansion EV1 Y1E
valve (Main)
Solenoid
valve (Hot SVP Y2S
gas)
Solenoid
valve
(Receiver SVG Y3S
gas
discharging)
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
40
In addition, outdoor unit heat exchanger co-efficiency is derived from Tc, Te, and the
compressor load.
Electric Symbol
RZR36/42P
RZQ36/42P
M1C
M1F
M2F
Y1S
Y1E
Y2S

Indoor unit actuator
Thermostat ON unit
Stopping unit
Thermostat OFF unit
Thermostat ON unit
Stopping unit
Thermostat OFF unit
Defrost preparation
Defrost operation
operation
52 Hz 177 Hz
STEP 8 OFF
ON OFF
SH control 1400 pls
OFF ON
ON ON
130 seconds OR
Special Control
Post Defrost
operation
2-step increase from
52 Hz to (Pc – Pe >
58 psi) every 20
seconds
STEP 8
ON
200~400 pls
ON
OFF
 15 minutes  160 seconds
OR
 Tb > 51.8F  Pc – Pe > 58 psi
During defrost
OFF
OFF
OFF
500 pls
500 pls
500 pls
Function and Control