Ver
sion:
M
P4/
6 G
3
08/
01
/2024
31
3.4.
Troubleshooting
Work on the system which requires tools, must only be carried out by authorised
installation engineers!
Ensure the boiler is disconnected from the power supply before starting work!
What has happened
Possible cause
No or insufficient heat.
Control valves in the system are restricting the flow.
Incorrect adjustment of the bypass valve. Check and
adjust.
A setpoint that is too low has been set on the boiler.
Check and adjust.
The boiler triggers the
over-temperature
protection prematurely.
Check the settings for Temp guard level and
Temp guard type in Installation Settings/Advanced/Syste
Settings. Read more about Temp guard on page 29.
The boiler’s display and
indicator lights are
turned off.
Check the fuses and that the boiler’s control switch is in
the
on position.
The group fuses for the
boiler are triggered.
The immersion heater is broken. Check by checking the
insulation of the immersion heater. Measure between the
outgoing side of the circuit board relay and earth.
Manual operation - test mode
In order to test the boiler’s functions when troubleshooting, you can control the power steps,
the circulation pump and the buzzer alarm relay manually. Read more about activating Manual operation
on page 28.
Troubleshooting boiler temperature sensor
The boiler temperature sensor must not be connected to the circuit
board during resistance measurement.
Measurement points on the circuit board
Values
°C
kΩ
Vdc
°C
kΩ
V
°C
kΩ Vdc
5
141.9
4.7
40 30.0 3.7
75
8.2
2.3
10
111.6
4.6
45 24.6 3.6
80
6.9
2.0
15
88.3
4.5
50 20.2 3.3
85
5.8
1.8
20
70.3
4.4
55
16.7
3.1
90
5.0
1.7
25
56.3
4.2
60
13.9 2.9
95
4.2
1.5
30
45.4
4.1
65
11.6 2.7 100
3.7
1.3
35
36.8
3.9
70
9.7 2.5