Application Brochure

3 of 8
- Application
Boiler Control 256
A 256-2
05/00
Copyright ©2000 A 256-2 05/00
Mechanical
Note: This is only a concept drawing. The designer must determine whether this application will work in his system and must ensure compliance with
code requirements. Necessary auxiliary equipment, isolation relays (for loads greater than the specified tekmar internal relay ratings), and other safety
and limit devices must be added.
Outdoor
Sensor (S2) 070
Class II
Transformer
120 V (ac)
24 V (ac)
P1
256
R1
M
M
M
T3
T2
T1
Boiler
Sensor
(S1) 071
Z3
Z2
Z1
Electrical
P1 = Boiler Pump
R1 = Relay 003
S1 = Boiler Sensor 071
S2 = Outdoor Sensor 070
T1, ..., T3 = Thermostats
U1 = tekmar Timer 031 (optional)
Z1, ..., Z3 = Zone Valve Motor End Switches
N
L
3
4
6
5
7
2
1
8
Boiler
S2
S1
U1
256
5
7
9
86
T
5A
Boiler
R+
C-
Power
Do not apply power
2
Sw
UnO
Out
3
Boil
14
Com
Z1
Z2
Z3
24 V (ac)
120 V (ac)
Class II
Transformer
C
R
P1
R1
Zone Valve
Motor End
Switches