tekmar 538 Thermostat Installation - Manual (Page 15)

15 of 24 © 2011 D 538 - 12/11
Heating Operation Section A
Sequence of Operation
When using only a room temperature sensor, the thermostat operates the heating
system to maintain the Set Room Heat temperature.
When using only a floor temperature sensor, the thermostat operates the heating
system to maintain the Set Floor Heat temperature. In this case, the thermostat
does not try to control the air temperature. This is ideal for bathrooms and some
kitchen applications where the customer wants their feet to feel warm on the floor.
This is also ideal for garages so that the heating system is not affected by the
opening of the garage door in cold outdoor weather.
When using both a room temperature sensor and a floor temperature sensor, the
thermostat always maintains the Floor Minimum temperature, even when the air
temperature is satisfied. When the air temperature is below the Set Room Heat
temperature, the thermostat operates the heating system to maintain the Set Room
Heat temperature. The floor is never heated above the Floor Maximum setting in
order to protect the floor covering.
The H1 symbol is shown on the display when the thermostat is heating. The heat
can cycle on and off within +/- 1.5°F (1°C) of the Set Room Heat temperature.
Freeze Protection ---------------------------------------------------- ----------------------------------------------------
The thermostat operates the heat whenever the room or floor temperature falls
below 40°F (4.5°C).
Exercising ---------------------------------------------------------- ----------------------------------------------------------
When connected to a tekmarNet ® reset control, 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 ------------------------------------------------------------ ------------------------------------------------------------
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 --------------------------------------- ---------------------------------------
When connected to a tekmarNet ® system control, the thermostat’s Heat Supply
Pump setting affects how the primary pump or mix pump on the system control
operates. When connected to the boiler bus, the boiler system or primary pump is
operated. When connected to the mix bus, the mix system pump is operated.
If the thermostat operates a motorized or thermal motor zone valve, the Heat Supply
Pump setting should be set to On.