8.5
Reduced output
Possible causes
Remedies
8.6
CH does not reach the correct temperature
8.7
No hot water (HW)
1. Tap flow < 2.0 l/min.
2. Replace the flow switch.
Flow switch does not switch.
1. Replace S3.
See burner does not ignite.
Burner does not ignite.
Yes
Burner does not come in on HW: S3 defect.
Yes
No
No
Yes
1. Check the wiring according to the
diagram.
No voltage on the flow switch (24 V).
Yes
No
Possible causes
Remedies
1. Check appliance and flue system
At high speed, the power has decreased
Yes
by not more than 5%.
for pollution.
2. Clean appliance and flue system.
Possible causes
1. Check the setting and adjust if
Room thermostat settings not correct.
Yes
necessary: set to 0.1 A.
No
1. Raise the pump setting or replace
the pump.
1. Check for circulation: at least 2 or 3
radiators must be open.
1. Adjust the power,
see Setting maximum CH power.
1. Descale or flush the heat exchanger
on the CH side.
No heat transfer due to scaling or pollution
in the heat exchanger.
Yes
The boiler power is not set well
for the system.
Yes
No
No
No circulation in the system.
Yes
Pump does not run well.
Pump setting too low.
Yes
No
No
1. Raise the CH temperature,
Temperature set too low.
see CH operation.
Yes
2. Check the outside sensor for
short circuit: remedy this..
Remedies
50