Installation and operating instruction
Oil condensing boiler WTC-OB 18-B
6 Operation
83311002 1/2018-03 La
54-132
6.9 Frost protection
Boiler frost protection
Flow temperature < 8 °C:
burner is operated at minimum load,
pump is in operation.
Supply temperature > 8 °C plus switching differential (parameter
32
):
burner switches off,
pump run-on is activated (parameter
41
).
Boiler frost protection also has a reaction on outputs MFA1 and VA1 if set as a
feed pump (parameter
13
,
14
,
15
).
When boiler frost protection is activated, the symbol
flashes in the display.
System frost protection (with external sensor)
External temperature < system frost protection (parameter
23
):
pump is activated every 5 hours. The power on time corresponds to the run-on time
of the pump (parameter
41
).
External temperature < system frost protection (parameter
23
) minus 5 Kelvin:
continuous pump operation is activated.
External temperature > system frost protection (parameter
23
):
continuous pump operation is deactivated.
The system frost protection also has a reaction on the outputs MFA1 and VA1 if set
as a heating circuit pump (parameter
13
,
14
,
15
).
With buffer control, the system frost protection has no affect on the boiler circuit
pump.
DHW frost protection(version W)
DHW temperature < 8 °C:
burner is operated at minimum load,
pump is in operation.
DHW temperature > 8 °C plus half switching differential (parameter
51
):
burner switches off.
The DHW frost protection also has a reaction on outputs MFA1 and VA1 if they are
set as circulation or DHW pumps (parameter
13
,
14
,
15
).
When DHW frost protection is activated, the symbol is flashing in the display.
