0020308119_02 Operating instructions 21
Symptom Possible cause Measure
Product does not start
up (no hot water,
heating remains cold)
The cold water stop
valve is closed.
▶ Open the cold water stop valve.
The product is
switched off.
▶ Restart the product. (→ Section 8)
The room temper-
ature/domestic hot
water temperature
has been set too
low and/or heating
mode/domestic hot
water mode has been
switched off.
1. Set the flow temperature.
(→ Section 4.4.1)
2. Set the domestic hot water temperature.
(→ Section 4.5.1)
There is air in the
heating installation.
1. Purge the heating installation (→ "Topping
up the heating installation" section).
2. If you are unable to purge the heating
installation yourself, contact a competent
person.
Heating will not start
(hot water generation
OK)
The external control is
not set correctly.
▶ Set the external control correctly (→ Control
operating instructions).