Table of Contents
3-way valve
B
A
B
AB
Thermistors
• Room temperature thermistor (TH1)
• Liquid refrigerant temperature thermistor (TH2)
• Flow water temperature thermistor (THW1)
• Return water temperature thermistor (THW2)
• DHW tank temperature thermistor (THW5)
• Zone 1 flow water temperature thermistor (THW6)
• Zone 1 return water temperature thermistor (THW7)
• Zone 2 flow water temperature thermistor (THW8)
• Zone 2 return water temperature thermistor (THW9)
Thermistor R0 = 15kΩ ± 3%
B constant = 3480 ± 2%
1
1
Rt = 15exp {3480 ( 273+t – 273 )}
0°C
15kΩ
10°C
9.6kΩ
20°C
6.3kΩ
25°C
5.2kΩ
30°C
4.3kΩ
40°C
3.0kΩ
• Boiler flow water temperature thermistor (THWB1)
• Boiler return water temperature thermistor (THWB2)
Thermistor R100 = 3.3kΩ ± 2%
B constant = 3970 ± 1%
1
1
Rt = 3.3exp {3970 ( 273+t – 273 )}
0°C
162.8kΩ
10°C
97.4kΩ
20°C
60.3kΩ
25°C
48.1kΩ
30°C
38.6kΩ
40°C
25.4kΩ
50°C
17.1kΩ
60°C
11.9kΩ
70°C
8.4kΩ
80°C
6.0kΩ
OCH570
Part Name
Motor
Indicator (red)
B
A
Release button
Valve
A
B
AB
(1) Check the movement of the red indicator. The red indicator normally points
to A in DHW mode and to B in Heating mode as shown to the left.
(2) If each indicator position is correct but the 3-way valve does not work prop-
erly, the motor may not fit onto the valve securely, so remove the motor by
pressing the release button, and reinstall it.
A
Disconnect the connector then measure the resistance with a tester.
(At ambient temperatures of 10 - 30°C.)
Thermistor
TH1
TH2
THW1
THW2
THW5
THW6
THW7
THW8
THW9
THWB1
THWB2
50
40
30
20
10
0
1000
900
800
700
600
500
400
300
200
100
0
-30 -20 -10
59
Check Points
Normal
Abnormal
4.3 - 9.5 kΩ
Open or short
40 - 100 kΩ
Open or short
-20 -10
0
10
20
30
40
Temperature (:)
0
10
20
30
40
50
Temperature (°C)
50
60
70
80
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