Application Brochure

1 of 4 © 2009 A 257 - 03/09
A 257
03/09
- Application Brochure
DHW Control 257
Mechanical
P1 = Boiler Pump 1
P2 = Boiler Pump 2
S1 = DHW Sensor 082
Electrical
S1 = DHW Sensor 082
DIP Switch Settings
Rotate = On
Application A 257-1
System Description:
The 257 stages 2 single-stage boilers in order to maintain the DHW Target temperature as measured by the DHW Sensor.
The boiler pumps operate off the boiler ignition control.
S1
P1
P2
DHW
Tan k
120 V (ac)
24 V (ac)
Class 2
Transformer
257
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.
Boiler 1 Boiler 2
24 V (ac)
N
R
C
120 V (ac)
Class 2
Transformer
L
S1
Rotate
On
Off
78
No Power
257
132
Heat 1Power
4 5
Heat 2 Com DHW
6
Sen SenRC