tekmar 374 Universal Reset Control - Manual (Page 7)

7 of 36 © 2009 D 374 - 03/09
BOILER CHARACTERIZED HEATING CURVE
The boiler(s) have a Boiler Characterized Heating Curve determined by
the following settings:
Boiler Design Temperature
The boiler design supply temperature is the supply water temperature
required to heat the building when the outdoor air temperature is as
cold as the outdoor design temperature.
Boiler Indoor Design Temperature
The indoor design temperature is the room temperature that was
used in the original heat loss calculations for the building. This setting
establishes the beginning of the boiler characterized heating curve.
Boil Room
The Boil Room setting is the desired room temperature for the building
and provides a parallel shift of the boiler characterized heating curve.
The room temperature desired by the occupants is often different from
the design indoor temperature. If the room temperature is not correct,
adjusting the
Boil Room setting increases or decreases the amount of
heat available to the boiler zones in the building. A Boil Room setting is
available for both the occupied (day) and unoccupied (night) periods.
BOILER TERMINAL UNITS
When a terminal unit is selected, the control automatically loads the boiler design temperature, boiler maximum supply temperature,
and boiler minimum supply temperature. The factory defaults can be changed to better match the installed system. If a factory
default has been changed, refer to section A to reload the factory defaults.
Terminal Unit High Mass
Radiant (1)
Low Mass
Radiant (2)
Fancoil
(3)
Fin-Tube
Convector (4)
Radiator
(5)
Baseboard
(6)
BOIL DSGN 120°F (49°C) 140°F (60°C) 190°F (88°C) 180°F (82°C) 160°F (71°C) 150°F (66°C)
BOIL MAX 140°F (60°C) 160°F (71°C) 210°F (99°C) 200°F (93°C) 180°F (82°C) 170°F (77°C)
BOIL MIN OFF OFF 140°F (60°C) 140°F (60°C) 140°F (60°C) 140°F (60°C)
Boiler Target Temperature
The boiler target temperature is determined from the boiler characterized heating curve settings and the outdoor air temperature.
The control displays the temperature that it is currently trying to maintain as the boiler supply temperature. If the control does not
presently have a requirement for heat, it does not show a boiler target temperature. Instead, “– – –” is displayed in the LCD.
Boiler Minimum
The boiler minimum is the lowest temperature that the control is
allowed to use as a boiler target temperature. During mild conditions,
if the control calculates a boiler target temperature that is below the
boiler minimum setting, the boiler target temperature is adjusted
to at least the boiler(s) minimum setting. During this condition, if
the boiler(s) is operating, the minimum segment is turned on in the
display when viewing either the boiler supply temperature or the
boiler target temperature. Set the boiler minimum setting to the boiler
manufacturer’s recommended temperature.
Boiler Maximum
The boiler maximum is the highest temperature that the control is
allowed to use as a boiler target temperature. If the control does target
the boiler maximum setting, and the boiler temperature is near the
boiler maximum temperature, the maximum segment will be displayed
in the LCD while either the boiler target temperature or the boiler supply
temperature is being viewed. At no time does the control operate the
boiler(s) above 248°F (120°C).
BOIL MAX BOIL DSGN
OUT DSGN
ROOM OCC
ROOM UNOCC
210
(99)
190
(88)
170
(77)
150
(66)
130
(54)
110
(43)
90
(32)
70
(21)
50°F
(10°C)
-20
(-29)
0
(-18)
20
(-7)
40
(5)
60
(16)
80
(27)
Outdoor Air Temperature
Supply W
a
ter T
e
mperatur
e
Boiler Characterized
Heating Curve
Boiler Characterized
Heating Curve
BOIL MIN
BOIL INDR
WWSD OCC
WWSD UNOCC
MIN Segment On
MAX Segment
On
MAX Segment
On