tekmar 257 DHW Control - Manual

1 of 12 © 2009 D 257 - 03/09
D 257
03/09
- Data Brochure
DHW Control 257
The DHW Control 257 is used for dedicated domestic hot water systems. The control operates two on/off boilers, or one
two-stage boiler to maintain the DHW Target temperature at the DHW Sensor. The control can operate in Proportional (P)
mode, or Proportional, Integral, Derivative (PID) mode.
Additional functions include:
Boiler rotation
Cumulative boiler run time hours
P or PID staging modes of operation
CSA and UL certified for use in the USA and Canada •
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DHW Control 257
Two Stage
Item
Dat
e Code
Power: 24 V ±10% 50/60 Hz 3 VA
Relays: 240 V (ac) 10 A 1/3 hp
tektra 906-11
Meets Class B:
Canadian ICES
FCC Part 15
Stage Mode Delay
Target DHW
Differential DHW
1 2 3 4
C R
7
Com
Sen
8
DHW
Sen
No Power
Signal wiring
must be rated
at least 300V
Made in Canada
Power Heat 1
5 6
H30
14
B
Heat 2
Rotate
On
Off
Input
Universal Sensor
Included
Output
Boiler
Output
Boiler
Input
24 V (ac)
Power Supply