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© 2010
D 540 - 08/10
Heating Operation
Section A
Sequence of Operation
The thermostat operates the heating system to maintain the Set Room Heat
temperature. The H1 symbol is shown on the display when the thermostat is
heating. The heat can cycle on and off /- 1.5°F (1°C) of the Set Room
Heat temperature.
Freeze Protection
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The thermostat operates the heat whenever the room temperature falls below 40°F
(4.5°C), regardless of the thermostat mode.
Heat Terminal Unit
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When the thermostat is connected to a tekmarNet
®
reset control, the heat source
can be either hydronic or non-hydronic.
When the Heat Terminal is set to Hydronic, the thermostat uses indoor temperature
feedback to fine tune the water temperature and also synchronizes the start of a
heating cycle so that all thermostats start heating at the same time. This reduces
cycling on the boiler.
When the Heat Terminal is set to Other, the thermostat does not use indoor
temperature feedback. This allows the thermostat to operate non-hydronic heating
systems (example: furnace, electric baseboard, or electric fan coil), while remaining
connected to the tekmarNet
®
system.
Exercising
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When connected to a tekmarNet
®
reset control, and the heating terminal unit is set
to hydronic, the thermostat exercises the heat relay for 10 seconds every 3 days.
Exercising helps prevent zone valves or zone pumps from failing due to precipitate
buildup. During exercising, the thermostat shows “TEST” on the display.
Flushing
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The flushing feature is for open-loop systems that use a domestic hot water tank
as a heat source. Flushing ensures that fresh potable water is circulated through
the system once each day. If the thermostat is connected to a tekmarNet
®
reset
control with the Flushing feature turned on, the thermostat display will display the
“FLUSH” icon for the duration of the flushing operation.
Hydronic System Supply Pump
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When connected to a tekmarNet
®
reset control, the thermostat’s Supply Pump
setting affects how the primary pump or mix pump on the reset control operates.
When connected to the boiler bus, the primary pump is affected. When connected
to the mix bus, the mix system pump is affected.
If the thermostat operates a motorized zone valve or a zone pump, the Supply
Pump setting should be set to On.
