Function Description - Viessmann VITOTRONIC300 Installation And Service Instructions Manual

Function Description

Boiler Water Temperature Control
Switching hysteresis, burner
ON
OFF
set
low heat
demand
ON
OFF
set
low heat
demand
ON
OFF
set
low heat
demand
78
average heat high heat
demand demand
average heat high heat
demand demand
average heat high heat
demand demand
Vitotronic 300, GW2B Installation and Service
(continued)
Permanent switching hysteresis
Code "04:0"
Heat demand-dependent switching hysteresis
The heat demand-dependent switching hysteresis takes
Time
the boiler load into account.
The switching hysteresis, i.e. the burner runtime varies
subject to actual heat demand.
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.
ERB50 function
Code "04:1"
Time
Subject to heat demand, values between 6 and 12 K
result.
ERB80 function
Code "04:2"
Time
Subject to heat demand, values between 6 and 20 K
result.