Application Brochure
7 of 8
- Application
Boiler Control 256
A 256-4
05/00
Copyright ©2000 A 256-4 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.
Electrical
A1 = DHW Aquastat
A2 = DHW High Limit Aquastat
P1 = DHW Pump
R1, ..., R4 = Relay 003
S1 = Boiler Sensor 071
S2 = Outdoor Sensor 070
T1, ..., T3 = Thermostats
U1 = tekmar Timer 031 (optional)
Z1, ..., Z3 = Zone Pumps
Boiler
3
4
6
5
7
2
1
8
3
4
6
5
7
2
1
8
24 V (ac)
120 V (ac)
Class II
Transformer
N
L
C
R
S2
S1
U1
256
5
7
9
8
6
T
5A
Boiler
R+
C-
Power
Do not apply power
2
Sw
UnO
Out
3
Boil
14
Com
3
4
6
5
7
2
1
8
R4
P1
A2
A1
R1
R2
R3
Z1
Z2
Z3
T3
T2
T1
3
4
6
5
7
2
1
8
Mechanical
Class II
Transformer
120 V (ac)
24 V (ac)
Outdoor
Sensor (S2) 070
DHW
Tank
256
Boiler
Sensor
(S1) 071
P1
R4
A1
A2
Z1 Z2 Z3
R1 R2 R3
T1 T2 T3