5
VIEGA 1-800-976-9819
PI-16015-03/09
2 Control operation
2.1 General operation
When the Basic Heating Control is
powered up, the control displays the
control type number in the LCD for 2
seconds. Next, the software version
is displayed for 2 seconds. Finally,
the control enters into the normal
operating mode.
The Basic Heating Control uses a
floating action mixing or injection valve
to vary the supply water temperature
to a hydronic system. The supply
water temperature is based on
the outdoor temperature.
The maximum water temperature
setting in the Basic Heating Control
should not be used as a safety high
limit control. To protect floors from
high water temperatures in case of
main control failure or removal, use a
Viega Modulating Safety High Limit
Control (stock code 16116) on the
outlet injection valve of the
Injection Station.
2.2 Control Features
2.2.1 outdoor Reset
The Basic Heating Control calculates
a mixing supply water temperature
based on the outdoor air temperature.
The Basic Heating Control uses a
heating curve and optional indoor
temperature feedback from an indoor
sensor in this calculation.
2.2.2 Floating action
A 24 V (AC) floating action actuator
motor is connected directly to
the Basic Heating Control on the
Com, Opn and Cls terminals (7, 8,
and 9). The Basic Heating Control
pulses the actuator motor open
or closed to maintain the correct
mixed supply water temperature at
the supply sensor. The valve that
the actuator is connected to can
be either an injection valve (on the
Injection Station), a mixing valve, or
a diverting valve. A visual indication
as to whether the control is currently
opening or closing the mixing valve
is displayed in the LCD.
2.2.3 Warm Weather shut Down
The Basic Heating Control monitors
the outdoor temperature and shuts
off the heating system seasonally
when outdoor temperatures exceed
the WWSD setting. This reduces
energy use during the summer
when the heating system is not
needed and saves wear on system
components. To prevent the system
from seizing due to long periods of
no use, the circulator, actuator, and
valve are exercised periodically (see
below).
2.2.4 Exercising
The Basic Heating Control has a
built-in exercising function. If the
system pump or valve has not
been operated at least once every
3 days, the control turns on the
output for a minimum of 10 seconds.
This minimizes the possibility of
a circulator pump or valve seizing
during a long period of inactivity.
The Basic Heating Control ensures
that the mixing valve operates over
its entire range at least once each
exercising period. While the control
is exercising, the Test LED flashes.
Note: The exercising function does
not work if power to the control,
circulator, or valve is disconnected.
ContRoL oPERAtIon - CHAPtER 2
