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

Vitodens 100-W, WB1B Installation & Service
Boiler Connection

Determining the boiler set-point

Outside temperature
Legend
A Selector dial "tr" setting: 1
B Selector dial "tr" setting: 2
C Selector dial "tr" setting: 3
Start-up and Maintenance
D Selector dial "tr" setting: 4
E Factory default
F Selector dial "tr" setting: 5
G Selector dial "tr" setting: 6
(continued)
Factory default
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.
Troubleshooting
79