Page 26
Page 27
SERVICING AND MAINTENANCE
FAULT FINDING
1
2
3
4
5
6
7
8
9
10
11
12
13
14
1
2
3
4
1
2
3
4
1
2
3
4
5
6
7
8
1
2
1
2
3
4
5
6
7
8
9
1
10
2 3
4 5 6
J18
J20
J19
J3
J7
J8
J1
TS sensor
GND GND
IN OUT
T1 T2
1
2
CW sensor
1
2
Combined flow
and
HW temperature
sensor
L - Brown
PR61
E – G/Y
N - Blue
PW
M
-
PW
M
+
SP
ARE
Fuse
Dip
Sw
itc
h
1 2 3 4
To
DHW
pipe
All the these sensor inputs carry a
Voltage of 5V.
The max cable length is 1 meter.
The sensors connected to the control
Should be free from the appliance earth
Resistance
Resistance
Ohm
°C
±°C
Ohm
°C
±°C
309396
-40
1.7
334275
-36
0.9
171840
-30
1.7
47369
-6
0.1
98932
-20
1.6
26023
5
0.1
58879
-10
1.5
11000
23
0.6
36129
0
1.4
10500
24
0.6
22804
10
1.4
10000
25
0.6
14773
20
1.3
9500
26
0.7
12000
25
1.2
9000
27
0.7
9804
30
1.2
8500
29
1.4
6652
40
1.1
8000
30
1.5
4607
50
1
7500
31
1.6
3252
60
0.9
7000
33
1.7
2337
70
1.1
6500
35
1.7
1707
80
1.3
6000
37
1.8
1266
90
1.5
5500
39
1.9
952
100
1.8
5000
41
2.1
4500
44
2.2
4000
47
2.3
3500
50
2.5
3000
54
2.7
2500
59
2.9
2000
65
3.3
1500
73
3.7
1000
86
4.3
R-nominal
R-nominal
B-value
B-value
R-Tolerance
R-Tolerance
Tmin
Tmin
Tmax
Tmax
125°C
under 25°C±0.025*T °C over 25°C±0.05*T °C
Huba combined flow sensor and NTC 10k thermistor
Tasseron NTC 12k thermistor
12Kohm @25°C
B3740K
3%@60°C
150°C
Temperature
Temperature
-40°C
-40°C
Used on the store temperature sensors and the
cold water inlet temperature sensors
12Kohm @25°C
B4050K
HZ
l/min
HZ
l/min
20
3.4
95
17.1
25
4.4
100
18.0
30
5.3
105
19.0
35
6.2
110
19.9
40
7.1
115
20.8
45
8.0
120
21.7
50
8.9
125
22.6
55
9.8
130
23.5
60
10.7
135
24.4
65
11.7
140
25.3
70
12.6
145
26.2
75
13.5
150
27.2
80
14.4
155
28.1
85
15.3
160
29.0
90
16.2
165
29.9
flow rate determination
SERVICING AND MAINTENANCE
FAULT FINDING
Check for presence of overheat link
An overheat link connection should be present in connection Junction 7. If you are
fitting a new board the overheat link that is on the board just removed must be retained
as the newly supplied board will not have one fitted.
Check outputs from the PWM controller PCB to the pump
PWM pump power
Check 230V ac across Junction 8, L(10) to E(6) and L(10) to N(8) (live test)
Check for 0-15V ac across Junction 8, N(8) to E(6) (live test)
PWM frequency
Power on the unit
Set the multi meter to measure the frequency
Measure the PWM frequency produced by the board between pins 3 on J8 and pin 9 on J8
This can be between 100Hz – 5000 Hz (1000Hz nominal)
(Lab tested figure of 562Hz recorded in steady state conditions).
Duty cycle
Switch your Multimeter to ‘duty cycle or %’ then it will show a percentage from 0 to 100%.
This percentage is the command for the pump how fast it should run.
When you perform a small DHW tapping, the percentage will be low
When you perform a large DHW tapping, the percentage will be higher
PWM input signal [%] indications
• 0-7 Pump stops (Standby)
• 7-15 Pump runs at minimum speed (operation)
• 12-15 Pump runs at minimum speed (start-up)
• 15-95 Pump speed increases linearly from minimum to maximum
• > 95 Pump runs at maximum speed
