© 2013
553_D - 04/13
32 of 48
A Watts Water Technologies Company
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.
A W HEAT WWSD setting is available to allow a forced air heating system to heat the
building while the radiant floor heat system is shut off during mild outdoor temperatures.
This is advantageous in the spring and fall when heating is required at night and cooling
is required during the day. As the outdoor temperature falls below the W HEAT WWSD
setting, the radiant floor becomes the primary heat source and the heat pump provides
supplemental heating.
Balance Point
-------------------------------------------------------
-------------------------------------------------------
An air source heat pump’s Coefficient Of Performance (COP) decreases with colder
outdoor temperature. This affects the heating output capacity of the heat pump to
heat the building. When the COP is equal to 1, the heat pump no longer provides an
economic advantage over electric heating elements or other supplemental heating fuel.
The outdoor temperature at which this occurs is known as the balance point. When the
outdoor temperature falls below the balance point, the heat pump is shut off and the
backup supplemental heat source is operated to heat the building. The 553 has the
ability for the balance point setting change based upon a programmable schedule. This
is useful in cases where the electrical utility offers different energy pricing throughout
the day.
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.
Two-Stage Heating
--------------------------------------------------
--------------------------------------------------
The 553 generally operates a radiant floor or baseboard as the first stage of heat and
a forced air heating system as the second stage. When an outdoor temperature sensor
is available, the 553 can change the order of the heat stages using the Radiant Floor
Warm Weather Shut Down or the Balance Point to operate the system as comfortably
and efficiently as possible. For additional control of the second stage operation, the
553 includes a time delay and a temperature differential setting. Both setting conditions
must be met before the second stage heat is allowed to turn on.
Warm Weather
Shut down
Radiant Floor Warm
Weather Shut Down
W2
Lockout
Balance
Point
Colder Outdoor
Temperature
