Panasonic Urban Multi MX1R Series Service Manual page 448

PACD011001C2
[Defrosting operation]
The defrosting operation provides the following control functions.
Step at which
preparation mode
is activated is set
as upper limit.
PI control
INV
SVP
PI control
Outdoor EV
50 sec
Indoor EV
Operate all indoor unit EV as follows : 1000 pls (50 sec) → 0 pls (10 sec) →4-way
(unit with
valve switching →0 pls (15 sec ∗5)
thermostat ON)
Normal control
Outdoor fan
Indoor fan
4-way valve
Signal output during oil
return/defrosting operation
preparation
2 min
Defrost Defrost IN
preparation
flag
[Defrosting operation ending conditions]
When the following conditions are met, the defrosting operation ends.
However, when the compressor stops during a defrosting operation, if condition (Tb > 12.5°C) is not met at
the next compressor startup, the defrosting operation starts and a 10-minute counter is activated when the
software startup is completed.
Function UM Combination "MA1R Series" Using R-407C
Defrost out
∗7
20 sec delay
52Hz+OFF
2000pls
500(∗4)
According to ∗6
OFF
Defrost
When distribution pipe temperatures at all heat exchanger
outlets (during cooling operation) are as follows: Tb > 12.5°C
OR
When defrosting operation is conducted for 10 minutes
∗1
PI control
67Hz+OFF
20 sec delay
30 sec
LP protection control after
this point
SH control
according to
PI control ∗3
∗2
SH control
Normal control
Hot start
Exhaust from accumulator
Outline of Control
∗1
Accumulator discharge operation ending
conditions
1 minute or more after
completion of defrosting
operation
&
OR
OR
Elapsed time of 10 minutes
∗2
SH control by outdoor unit EV
PI control activated when SHS = 10
(initial opening degree: 200 pls
In the case of an LP retry, the next PI
control is provided at SHS = 5.
When condition ∗1 is met, the next startup
condition is reset to SHS = 10.)
∗3
When returning to normal outdoor EV control,
the PI control is provided at that opening
degree.
∗4
Opening degree of indoor unit EV during
defrosting operation
• Initial value: 500
• Next indoor unit EV opening degree (200-
2000) is determined based on (Th6 – Te < 15)
appearing time in previous defrosting operation
0 minute → +100
Less than 3 minutes → +0
3 minutes or more → –100
∗5
0 pls maintained after elapsed time of 15
seconds until LP < 0.2 MPa
∗6
Opens receiver solenoid valve for 60 seconds at
1 minute after the preparation mode is
activated.
However, the valve is closed when Th6 – Te < 0.
∗7
CU-8MA1XPK 52Hz + ON
CU-10MA1XPK 71Hz + ON
CU-16, 20MA1XPK 52Hz + ON + ON
DSHi>30
Th6 – Te>10
LP<0.1MPa
(V0807)
427