tekmar 370 House Control User Manual
Page 15
Copyright © D 370 -06/99
15 of 20
Minimum Boiler Supply
Most boilers require a minimum operating temperature to prevent corrosion from flue gas
condensation. The
Min. Boiler Supply dial should be set to the lowest supply water
temperature at which the boiler can operate without causing the boiler flue gases to
condense. Consult the boiler manufacturer for recommended minimum boiler supply
temperatures. Some typical settings are given below. If a condensing or electric boiler is
used, the
Min. Boiler Supply dial can be set to Off.
Typical settings:
• Steel fire tube boilers . . . . . . 140 to 160
°F (60 to 71°C)
• Cast iron boilers . . . . . . . . . . 135 to 160
°F (57 to 71°C)
• Copper tube boilers . . . . . . . 135 to 150
°F (57 to 66°C)
Maximum System Supply
−
−
−
−
−
If the 370 is used in
Boiler mode, the 370 helps prevent the boiler supply water
temperature from rising above the
Max. System Supply dial setting. If the 370 is used
in
Mixing mode, the 370 helps prevent the mixed supply water temperature from
rising above the
Max. System Supply dial setting. The Max. System Supply dial should
be set to the maximum temperature allowed in the system loop. There are many
factors which may limit the allowable supply temperature in a radiant floor heating slab.
A few of these are provided below.
• Some tubing manufacturers recommend that their products not be maintained at
temperatures exceeding 140
°F (60°C). Consult the tubing manufacturer for
specific details.
• No where in the concrete should the temperature be maintained above 170
°F (77°C).
• The surface temperature of a radiant floor heating slab should normally not exceed
85
°F (29°C). The slab surface temperature is affected by the slab thermal resistance
and the supply water temperature to the slab.
Unoccupied Temperature
−−−−−−−−−−−
−−−−−−−−−−−
−−−−−−−−−−−
−−−−−−−−−−−
−−−−−−−−−−−
The
UnOccupied dial sets the desired indoor temperature during UnOccupied (Night
Setback) mode. When a Zone Control is used, the zones connected to the Zone Control
are not affected by the
UnOccupied dial on the 370. The Zone Control has its own
UnOccupied mode which is explained in more detail in the Data Brochure supplied with
the Zone Control.
Heating Curve
−−−−−−−−−−−−−
−−−−−−−−−−−−−
−−−−−−−−−−−−−
−−−−−−−−−−−−−
−−−−−−−−−−−−−
The
Heating Curve dial setting determines the number of degrees the supply water
temperature is raised for every one degree drop in outdoor temperature. The
Heating
Curve dial position can be calculated from the following formula.
design supply temperature – desired room temperature
Heating Curve =
desired room temperature – design outdoor temperature
Example: A system is designed to supply 120
°F (49°C) water when the outdoor
temperature is 10
°F (-12°C). The desired room temperature is 70°F (21°C).
120 - 70
°F (49 - 21°C)
50
°F (28°C)
Heating Curve
=
=
= 0.8
70 - 10
°F (21 - (-12)°C)
60
°F (16°C)
If the design supply water temperature is unknown, the
Heating Curve dial can be set to
a trial value using the typical design supply water temperatures given below.
Typical design supply temperatures:
• Hydronic radiant floors …......100 to 130
°F (38 to 54°C)
• Baseboard radiators …..........160 to 190
°F (71 to 88°C)
• Fan coils …............................180 to 210
°F (82 to 99°C)
DIP Switch Settings
−
−
−
−
−
Max. System
Supply
120
170
°F
220
130
°F
Off
165
Min. Boiler
Supply
100
70
°F
(21
°C)
40
(4)
100
(38)
UnOccupied
0.2
2
3.6
1
3
Heating Curve
Outdoor air temperature
50
(10)
30
(-1)
10
(-12)
-10
(-23)
70
(21)
3.6 3.0 2.4 2.0
1.6
1.2
0.8
0.4
1.0
0.6
90
(32)
WWSD
Point
°F
(
°C)
Supply water temperature
110
(43)
70
(21)
90
(32)
210
(99)
170
(77)
150
(65)
130
(54)
190
(88)
0.2
Settings