tekmar 261 Boiler Control - Manual (Page 7)

Copyright © D 261 - 0 3/09 7 of 20
Fancoil (3)
A fancoil terminal unit or air handling unit (AHU) consists of a hydronic heating coil and
either a fan or blower. Air is forced across the coil at a constant velocity by the fan or
blower, and is then delivered into the building space.
Default values: BOIL DSGN = 190
°F (88°C), BOIL MAX = 210°F (99°C),
BOIL MIN = 140
°F (60°C)
Fin–tube Convector (4)
A convector terminal unit is made up of a heating element with fins on it. This type of
terminal unit relies on the natural convection of air across the heating element to deliver
heated air into the space. The amount of natural convection to the space is dependant
on the supply water temperature to the heating element and the room air temperature.
Default values: BOIL DSGN = 180
°F (82°C), BOIL MAX = 200°F (93°C),
BOIL MIN = 140 °F (60°C)
Radiator (5)
A radiator terminal unit has a large heated surface that is exposed to the room. A radiator
provides heat to the room through radiant heat transfer and natural convection.
Default values: BOIL DSGN = 160
°F (71°C), BOIL MAX = 180°F (82°C),
BOIL MIN = 140 °F (60°C)
Baseboard (6)
A baseboard terminal unit is similar to a radiator, but has a low profile and is installed at
the base of the wall. The proportion of heat transferred by radiation from a baseboard is
greater than that from a fin-tube convector.
Default values: BOIL DSGN = 150
°F (66°C), BOIL MAX = 170°F (77°C),
BOIL MIN = 140 °F (60°C)
Section B3: Advanced
BOILER INDOOR (BOIL INDR)
The BOIL INDR is the room temperature used in the original heat loss calculations for the building. This setting establishes the
beginning of the
Characterized Heating Curve for the boiler zones.
BOILER DESIGN (BOIL DSGN)
The BOIL DSGN temperature is the supply water temperature required to heat the boiler zones when the outdoor air temperature is as
cold as the OUTDR DSGN temperature.
BOILER MAXIMUM (BOIL MAX)
The BOIL MAX is the highest water temperature that the control is allowed
to calculate as the BOIL TARGET temperature. If the control does target
the BOIL MAX setting, and the BOIL temperature is near the BOIL MAX
temperature, the MAX segment will be displayed in the LCD while either
the BOIL TARGET temperature or the BOIL temperature is being viewed.
At no time does the control operate the boiler above 248
°F (120°C).
BOILER MINIMUM (BOIL MIN)
The BOIL MIN is the lowest water temperature that the control is allowed
to use as the BOIL TARGET temperature. During mild conditions, if the
261 calculates a BOIL TARGET temperature that is below the BOIL
MIN setting, the BOIL TARGET temperature is adjusted to at least the
BOIL MIN setting. During this condition, if the boiler is operating, the
MIN segment turns on in the LCD while the BOIL TARGET or BOIL
temperature is being viewed. If the installed boiler is designed for low
temperature operation, set the BOIL MIN adjustment to OFF.
WWSD OCC
ROOM OCC
70
(21)
90
(32)
110
(43)
130
(54)
150
(66)
170
(77)
190
(88)
Outdoor Air Temperature
Supply W
ater
T
emperature
210 °F
(99 °C)
-20
(-29)
0
(-18)
20
(-7)
40
(5)
60
(16)
80 °F
(27 °C)
BOIL DSGN
BOIL MIN
WWSD UNOCC BOIL INDR
OUTDR DSGN
Boiler Characterized
Heating Curve
50
(10)
ROOM UNOCC
BOIL MAX