Vitotronic 300, GW2B Installation and Service
5693 982 - 04
78
Boiler Water Temperature Control
(continued)
Permanent switching hysteresis
Code “04:0”
Heat demand-dependent switching hysteresis
The heat demand-dependent switching hysteresis takes
the boiler load into account.
The switching hysteresis, i.e. the burner runtime varies
subject to actual heat demand.
Function Description
ERB50 function
Code “04:1”
Subject to heat demand, values between 6 and 12 K
result.
Switching hysteresis, burner
low heat
demand
average heat
demand
high heat
demand
Time
ON
OFF
set
Burner
low heat
demand
average heat
demand
high heat
demand
Time
ON
OFF
set
Burner
ERB80 function
Code “04:2”
Subject to heat demand, values between 6 and 20 K
result.
low heat
demand
average heat
demand
high heat
demand
Time
ON
OFF
set
Burner
Control sequence
Boiler goes cold
(set value
−
2 K)
The burner start signal is selected as the set boiler water
temperature minus 2 K, and the burner starts its own
monitoring program.
Note:
The burner start may be delayed by a few minutes
subject to the number of auxiliary circuits and the
combustion type.
Boiler heats up
The burner stopping point is determined by the shutdown
differential (coding address “13” in the “boiler” group.
