Mitsubishi Electric City Multi PQHY-P72 Service Handbook page 122

Symbols
Part
(func- Notes
name
tions)
Ther- TH11
mistor (Dis-
charge)
TH6
(Inlet wa-
ter tem-
perature)
TH9
(Outlet
water
tempera-
ture)
THINV
THHS Heat sink
Inverter
heat sink
tempera-
ture
Solenoid SV1
valve Dis-
charge-
suction
bypass
SV4a-
SV4d
Heat ex-
changer
capacity
control
SV7a,7b,
7c
Usage
1. Detects discharge air temper-
ature
2. Provides high-pressure pro-
tection
0°C[32°F] : 698kohm
10°C[50°F] : 413kohm
20°C[68°F] : 250kohm
30°C[86°F] : 160kohm
40°C [104°F] :104kohm
50°C[122°F] : 70kohm
60°C[140°F] : 48kohm
70°C[158°F] : 34kohm
80°C[176°F] : 24kohm
90°C[194°F] : 17.5kohm
100°C[212°F] :13.0kohm
110°C[230°F] : 9.8kohm
1. Detects heat source unit inlet
water temperature
2. Operates the solenoid valve of
the heat exchanger for capac-
ity control
Water heat exchanger freeze
prevention
Controls the opening of the LEV
that regulates the refrigerant flow
to the inverter cooling heat ex-
changer
Controls inverter cooling fan
based on THHS temperature
1. High/low pressure bypass at
start-up and stopping, and ca-
pacity control during low-load
operation
2. High-pressure-rise prevention
Controls heat source unit heat
exchanger capacity
- 113 -
[ VI Refrigerant Circuit ]
Specifications
R = 7.465k
120
R = 4057
25/120
R =
t
1 1
7.465 exp
4057
393
R = 15k
0
R = 3460
0/80
1 1
exp
R = 15
3460
t
273
0°C[32°F] : 15kohm
10°C[50°F] :9.7kohm
20°C[68°F] :6.4kohm
25°C[77°F] :5.3kohm
30°C[86°F] :4.3kohm
40°C [104°F]:3.1kohm
R = 17k
50
R = 4170
25/120
1 1
R = 17 exp
4170
t
323
0°C[32°F] : 181kohm
10°C[50°F] :105kohm
20°C[68°F] : 64kohm
25°C[77°F] : 50kohm
30°C[86°F] : 40kohm
40°C [104°F]: 26kohm
AC208/230V
Open while being powered/
closed while not being powered
AC208/230V
Closed while being powered/
open while not being powered
Check
method
Resis-
tance
check
Resis-
tance
check
Continuity
check with
a tester