Application Brochure

© 2007 A 279 - 12/07 2 of 4
Electrical
Application A 279-2
System Description: The Steam Control 279 regulates the indoor temperature based on firing time of the steam boiler.
The firing time of the steam boiler is based on outdoor temperature, condensate return temperature, user control settings
and indoor sensors. The condensate return sensor provides information to the control to determine when the boiler has
produced enough steam to reach the furthest radiator to start the boiler percent on time. The indoor sensor provides
indoor temperature feedback to prevent over and under heating of the building.
Mechanical
Concept Drawing: This is only a concept drawing, not an engineered drawing. It is not intended to describe a complete system, nor any particular system. It is up to the
system designer to determine the necessary components for and configuration of the particular system being designed, including additional equipment, isolation relays
(for loads greater than the control’s specified output ratings), and any safety devices which in the judgement of the designer are appropriate, in order to properly size,
configure and design that system and to ensure compliance with building and safety code requirements.
115 V (ac)
A5
S3S1 S2
S4
Outlet: DHW Water
Inlet: City Water
S5
279
A2
Zone 2
A1
Zone 1
A3
Zone 3
A4
Zone 4
S1, S2 = Indoor Sensors 076, 077 or 084
S3 = Outdoor Sensor 070
S4 = Condensate Sensor 071
S5 = DHW Sensor 082
A1...A4 = Air Vents
A5 = Main Air Vent
S1, S2 = Indoor Sensors 076, 077 or 084
S3 = Outdoor Sensor 070
S4 = Condensate Sensor 071
S5 = DHW Sensor 082
N
115 V (ac)
L
S4
S5
S2
S1
S3
Boiler
14
Sen
13
S1
12
S2
11
Sen
10
Sen
9
Sen
15
Sen
16
Sen
Do not apply power
279
N
52
Power
L
634 7
Boiler Com Com DHW Indr Indr Com Cdn Out
8
Alert 2Alert 1
High Low
1
Optional
Alert
Panel
Low
Alert
Optional
Alert
Panel
High
Alert