Determining The Boiler Set-Point - Viessmann VITODENS 100-W WB1B Series Installation And Service Instructions Manual

Correction

Determining the boiler set-point

Start-up and Maintenance
Outside temperature
Legend
Start-up and Maintenance
A Selector dial "tr" setting: 1
B Selector dial "tr" setting: 2
C Selector dial "tr" setting: 3
D Selector dial "tr" setting: 4
E Factory default
F Selector dial "tr" setting: 5
G Selector dial "tr" setting: 6
Fig. 72
Factory default
Troubleshooting
Room dependent control:
Outdoor temperature sensor not
connected
With no outdoor sensor installed, the
"tr" dial will provide a constant
temperature set-point for the boiler
based on the dial position selected.
Setting the dial between 1 and 6 will
provide a set-point value of 81º F to
178º F / 27º C to 81º C respectively.
The dot between 4 and 5 represents
the factory default set-point value of
140º F / 60º C.
Weather dependent control:
Outdoor temperature sensor
connected
With the outdoor sensor connected,
the boiler will automatically recognize
the sensor and switch the set-
point dial operation from constant
temperature calculated to outdoor
reset calculated.
Adjusting the "tr" dial will select
the heating curve corresponding with
the heating curve chart. The set-point
will be calculated from the design
boiler water temperature associated
with the heating curve selected, and
reset from the actual outdoor air
temperature. Setting the dial between
1 and 6 will select the corresponding
curve from the chart. The dot
between 4 and 5 is the factory
default curve.
Note:
Both the room dependent control and
the outdoor reset control strategies
require a closed contact at terminals
RT to generate a call for heat to the
boiler.
Setting the dial to "0" places the
boiler in freeze protection mode
regardless of the control option
selected or the contact position at RT.
69