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Room Occupied and Unoccupied
The Room setting is the desired temperature of the building .
When a programmable schedule is used, there are both Room
Occupied and Room Unoccupied settings available . When the
programmable schedule is turned off, only the Room setting
is available .
Indoor Sensor Not Installed
When an indoor sensor is not connected to the control, the
Room setting operates as a parallel shift of the heating curve .
This allows fine tuning of the heating system . If the Room set-
ting is set above the Indoor Design setting, the entire heating
curve is shifted higher, resulting in longer heat on times being
calculated . Similarly, if the Room setting is set below the Indoor
Design setting, the entire heating curve is shifted lower, resulting
in shorter heat on times being calculated .
Indoor Sensor
Installation of an optional Indoor Sensor will provide better
temperature control compared to no indoor sensor installations .
When installed, the control automatically adjusts the heating
curve up or down to so that the ambient air temperature
reaches the Room Target . If the ambient temperature exceeds
the Room Target by 1°F (0 .5°C), the control sets the Heat On
time to zero and turns off the steam boilers .
Indoor Sensor Options
The control is compatible with indoor sensor models 076, 077
and 084 .
The temperature accuracy within the building can be improved
by installing a square number (4, 9, 16, 25) of sensors wired in
series-parallel to the auxiliary sensor input .
28
A = Outdoor Start
B = Boiler Start %
C = Outdoor Design
D = Boiler Design %
Boiler Cycled
Boiler Cycled
A, B
80
70
60
50
40
Outdoor Air Temperature
80
70
60
50
40
Outdoor Air Temperature
Indoor Sensors 084, 077 and 076
To Indoor Sensor Input
- 100%
C, D
C, D
- 90%
- 80%
- 70%
- 60%
- 50%
- 40%
- 30%
On/Off
On/Off
- 20%
- 10%
- 0%
30
20
10
0 (°F)
- 100%
- 90%
- 80%
75%
75%
- 70%
65%
65%
- 60%
- 50%
42%
42%
- 40%
- 30%
- 20%
- 10%
- 0%
30
20
10
0 (°F)
Series - Parallel
Wiring
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