7
VIEGA 1-800-976-9819
PI-16015-03/09
4 Boiler Control
4.1 Boiler operation
When the Basic Heating Control
determines that boiler operation
is required, the Boiler contact
terminals (5 and 6) close. While the
Boiler contact is closed, the burner
segment in the LCD is displayed.
4.2 Boiler Enable
(Boiler Enable 30% / Boiler Enable
10%)
The Basic Heating Control has
a DIP switch that allows for the
selection between a 30% boiler
enable and a 10% boiler enable.
In the 30% position, the Basic
Heating Control closes the boiler
contact when the position of the
mixing valve exceeds 30%. The
boiler contact remains closed until
the position of the mixing valve
reduces below 15%. This setting
would normally be chosen for low
mass boilers (copper fin tube, etc.),
or systems with low thermal mass in
the loop between the boiler and the
mixing valve (recommended for most
Viega applications).
In the 10% position, the Basic
Heating Control closes the boiler
contact when the position of the
mixing valve exceeds 10%. The
boiler contact remains closed until
the position of the mixing valve
reduces below 5%. This setting
is normally chosen for high mass
boilers (cast iron, steel fire tube, etc.)
or systems with large thermal mass
in the loop between the boiler and
the mixing valve.
BoILER ContRoL - CHAPtER 4
