© 2013
400_D - 09/13
21 of 32
Sequence of Operation
tekmarNet
®
System
Section A
tekmarNet
®
is a family of products that use communication
to operate the HVAC system in a comfortable and efficient
manner. The House Control is the central component in
a tekmarNet
®
system and requires tekmarNet
®
2 (tN2)
Thermostats to be directly connected to the control.
The tekmarNet
®
4 (tN4) Expansion terminals can link the
House Control with other tekmarNet
®
components:
Wiring Centers 313, 314, 315, 316 - Add additional zones
tN2 and tN4 Thermostats - Add thermostats
tN4 Timer 033 - Adds 4 programmable schedules
tN4 User Switch 479 - Provides a system override for
vacations and holidays
tN4 Setpoint Control 161 - Control hot tubs, pools and
more
•
•
•
•
•
Boiler Temperature Reset Operation
Section B
Boiler Expansion Call
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Boil Exp
Calls
When a device connected to the tN4 Boil Expansion
terminals calls for heat, the House Control registers a Boil
Expansion call for hydronic heating on the boiler loop.
Boiler Target
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When there are no Boiler calls, the boiler target in the View
menu on the display will show ‘– – –’ to indicate there is
no requirement for boiler operation.
Once a Boiler Call is present, a boiler target is determined by
the control using the boiler heating curve (boiler minimum,
boiler design and outdoor design settings) together with
indoor temperature feedback from the thermostats. The
heating curve operates based on the principle that a buildings
heat loss increases with colder outdoor temperatures. The
calculated Boiler Target will be shown in the View menu
on the display.
Boiler Minimum
The House Control protects non-condensing boilers from
sustained flue gas condensation and thermal shock through
the Boiler Minimum setting. The boiler minimum is the
lowest temperature that the control is allowed to use as a
boiler target temperature. If the boiler is operating at the
boiler minimum temperature, the “MIN” segment is turned
on in the display when viewing either the boiler supply
temperature or the boiler target temperature.
Boiler Heating Curve
(70°F Outdoor,
Boiler Minimum)
Decreasing Outdoor Temperatures
Increasing W
a
ter T
e
mperatures
(Outdoor Design,
Boiler Design)
Boiler Maximum
The control has a fixed boiler maximum temperature of +
10°F (+5.5°C) higher than the Boiler Design setting for the
Boiler Heating Curve. When this occurs, the “MAX” segment
will display when viewing the boiler target or boiler supply
temperature in the view menu. The control will operate
the boiler so that the boiler supply temperature will never
exceed 210°F (99.0°C).
