Application Brochure

5 of 8
- Application
Boiler Control 256
A 256-3
05/00
Copyright ©2000 A 256-3 05/00
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.
Mechanical
M
MM
Class II
Transformer
120 V (ac)
24 V (ac)
Outdoor
Sensor (S2) 070
256
DHW
Tank
Boiler
Sensor
(S1) 071
P1
R2
R1
P2
A2
A1
T1T2T3
Z1Z2Z3
Electrical
A1 = DHW Aquastat
A2 = DHW High Limit Aquastat
P1 = Boiler Pump
P2 = DHW Pump
R1, R2 = 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
Zone Valve
Motor End
Switches
S2
S1
Boiler
3
4
6
5
7
2
1
8
C
R
N
L
U1
3
4
6
5
7
2
1
8
256
5
7
9
86
T
5A
Boiler
R+
C-
Power
Do not apply power
2
Sw
UnO
Out
3
Boil
14
Com
24 V (ac)
120 V (ac)
Class II
Transformer
R1
R2
P2
P1
A2
A1
Z1
Z2
Z3