Automatic Operation Of Pump For Freeze-Up Protection - Mitsubishi Electric CAHV-P500YA-HPB Service Handbook

[ VII Control ]
Control Method

-12- Automatic operation of pump for freeze-up protection

1. Purpose
This is a function to protect the water circuit from freezing up in winter.
2. Pump wire connection
blue
CN511
7 6 5
SV2
3. Natural freeze-up protection
The units will operate according to the dip switch SW2-1 on the control board as shown in the table below.
Dip switch settings
Control method
Details
HWE10060
LED2:CPU in operation
Contorol
power circuit
yellow
CN510
CN512
4 3 2 1 7 6 5 4 3 2 1 7 6 5 4 3 2 1
75 74 73 72 71 70
TB5
No-voltage contact output
Pump start conditions
Pump stop conditions
MB Transmission cable for multiple unit control
MA Measurement terminal for maintenance(M-NET)
TB6
CN52C
72C
red
CNDC
Pink
51P
52P
X20
X21
52P
PL
pump error
F2
ELB2
power supply
3N~
50Hz
380/400/415V
SW2-1 OFF
Natural freeze-up protection based
on both the outside temperature
and the water temperature
"Outside temperature is within ±1 ºC
of 1 ºC" OR "Inlet water
temperatureis within ±1 of 3 ºC "
"Outside temperature is more than
±1ºC of 3 ºC" OR "Inlet water
temperature is more than
±1ºC of 5 ºC"
- 88 -
B
TO SUB BOX TB3
A
M
MP
3~
H20 H21
X20 X21
L1 L2 L3 N
SW2-1 ON
Natural freeze-up protection
based on both the outside tem-
perature and the water tempera-
ture
Same as left
Same as left
GB