tekmar 264 Boiler Control - Manual (Page 21)

21 of 32 © 2008 D 264 - 12/08
DHW Demand
If a DHW demand is used, measure the voltage between the
Setp / DHW and the Com Dem terminals (8 and 7). When the DHW
demand device calls for heat, a voltage between 20 and 260 V
(ac) should be measured at the terminals. When the DHW demand
device is off, less than 5 V (ac) should be measured.
Setpoint Demand
If a setpoint demand is used, measure the voltage between the
Setp / DHW and the Com Dem terminals (8 and 7). When the setpoint
demand device calls for heat, you should measure between 20 and
260 V (ac) at the terminals. When the setpoint demand device is off,
you should measure less than 5 V (ac).
External Input
If an external input is used, measure the voltage between the
Com – and the Out + terminals (1 and 4). When the external input
device calls for heat, you should measure between 0 and 10 V (dc)
at the terminals.
V 20 to 260 V (ac) 7
8
Com
Dem
Setp/
DHW
1 2 3
4
Com
–
Boil
Ret
Out
+
Boil
Sup
500Ω
0 - 10 V (dc) 0 - 20 mA OR
V