Special Control
SiENBE18-621
70
Function
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)
$
Low pressure equivalent saturation temperature (Te)
$
Timer (2 hours at the minimum)
In addition, outdoor heat-exchange co-efficiency is derived from Tc, Te, and the compressor
load.
* From the preparing operation to the defrost operation, and from the defrost operation to the
operation after defrost, the compressor stops for 2 min. to reduce noise on changing of the four
way valve.
Outdoor unit actuator
Defrost preparation
operation
Defrost operation
Post Defrost operation
Compressor
Upper limit control
124 Hz Full load
2-step increase from
36 Hz Unload to
(Pc - Pe>0.4 MPa)
every 20 sec.
Outdoor unit fan
STEP8
OFF
STEP8
Four way valve
ON
OFF
ON
Main electronic expansion valve
(EV1)
SH control
480 pls
55 pls
Subcooling electronic expansion
valve (EV3)
0 pls
0 pls
0 pls
Hot gas bypass valve (SVP)
OFF
ON
ON
Ending conditions
2 min.
•
15 min.
•
Tb>11°C
•
Ts1 - Te<5°C
•
160 sec.
•
Pc - Pe>0.4MPa
or
&
{
or
Indoor actuator
During defrost
Indoor unit fan
Thermostat ON unit
OFF
Stopping unit
OFF
Thermostat OFF unit
OFF
BP unit electronic expansion
valve
Thermostat ON unit
SH control
Stopping unit
80 pls
Thermostat OFF unit
SH control
Summary of Contents for BPMKS967B2B
Page 1: ...SiENBE18 621 E Series Service Manual Applied Models Super Multi Plus Heat Pump...
Page 12: ...SiENBE18 621 List of Functions 1 Part 1 List of Functions 1 List of Functions 2...
Page 19: ...List of Functions SiENBE18 621 8 List of Functions...
Page 33: ...Specifications SiENBE18 621 22 Specifications...
Page 69: ...Refrigerant Flow for Each Operation Mode SiENBE18 621 58 Refrigerant Circuit...
Page 121: ...Indoor Unit SkyAir Models SiENBE18 621 110 Function...
Page 169: ...Instruction SiENBE18 621 158 System Configuration FTXS 20 25 35C Indoor Unit...
Page 371: ...Method of Replacing The Inverter s Power Transistors Modules SiENBE18 621 360 Troubleshooting...
Page 393: ...SiENBE18 621 vi Index...