Defrosting Operation - Daikin CMSQ200A7W1B Service Manual

Special Control
3.3

Defrosting Operation

To defrost the outdoor unit heat exchanger while in Evaporator, the defrost operation is conducted to recover the
heating capacity.
[Start conditions]
Referring to the set conditions for the following items, start the defrosting operation.
• Heat transfer coefficient of the outdoor unit heat exchanger
• Heat exchange temperature (Tb)
• Timer (Set to two hours at minimum.)
Furthermore, the heat transfer coefficient of the outdoor unit Evaporator is computed from Tc, Te, and compressor
loads.
Outdoor unit actuator
Compressor
Outdoor unit fan
Four way valve
Main motorized valve (EV1)
Subcooling motorized valve (EV2)
Hot gas bypass valve (SVP)
Accumulator oil return valve (SVO)
Injection (SVT) (CMSQ200A7 model only)
Ending conditions
Fan
Electronic expansion valve
42
Defrost preparation
operation
Upper limit control
STEP7
or
STEP8
ON
SH control → 480 pls
0 pls
OFF
ON
OFF
170 sec.
Indoor unit actuator
Thermostat ON unit
Stopping unit
Thermostat OFF unit
Thermostat ON unit
Stopping unit
Thermostat OFF unit
Defrost operation
176 Hz
OFF
OFF
480 pls
0 pls
OFF
ON
OFF
• 10 min.
or
• Tb>11°C
During defrost
Defrost EV opening degree
Defrost EV opening degree
SiBE28-805
Post Defrost operation
124 Hz
2-steps increase/20sec.
till Pc - Pe>0.4 MPa
STEP8
ON
55 pls
0 pls
OFF
ON
OFF
• 10 sec.
or
• Pc - Pe>0.4MPa
OFF
OFF
OFF
256 pls
Function