Install Instructions

© 2015 554_D - 02/15
30 of 44
A Watts Water Technologies Company
Sequence of Operation
Heating Operation
Set Heat Temperature ------------------------------------------------
When using only a room temperature sensor, the thermostat operates the heating
system to maintain the Set Heat Room temperature. The “Heat On” symbol is shown
on the display when the thermostat is heating.
Floor Heating --------------------------------------------------------
When using both a room and a floor temperature sensor, the floor is heated at least to
the Floor Minimum setting. If the room air temperature requires additional heating, the
floor temperature is increased until the air temperature reaches the Set Heat Room
setting. At no time is the floor heated above the Floor Maximum setting. This protects
the floor covering. A combination of floor and air temperature sensors is recommended
for areas with south facing windows with large solar gains and to protect wood floor
from over heating.
Suggested Floor Maximum settings are 90°F (32°C) for tile, stone, or concrete floors
and 85°F (29°C) for wood floors.
Radiant Floor Baseload ----------------------------------------------
When the terminal unit is a Hydronic Radiant Floor (HRF1 or HRF2) and no floor
temperature sensor is installed, the thermostat can optionally provide baseload heating.
This allows the radiant floor to be heated even though the room air temperature is
satisfied. This is useful in areas where a radiant floor heating zone is overlapped by
an air heating system. The radiant floor heating is overwhelmed by the quick heat-up
rate of the air heating system, resulting in a radiant floor heating zone that rarely turns
on. The radiant baseload option allows the radiant floor to counteract the air heating
system by heating the floor at a reduced output even when the room air temperature is
satisfied. This is also useful in areas that experience large solar gains through windows.
The radiant baseload is automatically shut off in the summer by the Warm Weather
Shut Down feature.
Warm Weather Shut Down --------------------------------------------
When the outdoor air temperature exceeds the Warm Weather Shut Down (WWSD)
setting on the tekmarNet
®
main control, the heating system is shut off.
Freeze Protection ----------------------------------------------------
The thermostat operates the heat whenever the room or floor temperature falls below
40°F (4.5°C) even when the mode is set to off.