tekmar 667 Snow Detector & Melting Control Installation - Manual (Page 15)

15 of 32 © 2009 D 667 - 03/09
Melt / Idle Demand
To generate a melt demand or idle demand, a voltage between 24 V (ac) and
240 V (ac) must be applied across the Melt / Idle Demand terminals (15 and 16).
Output Connections
Boiler Contacts
The Boiler terminals (19 and 20) are an isolated output in the 667. There is no power
available on these terminals from the control. These terminals are used as a switch
to either make or break the boiler circuit. When the 667 requires the boiler to fire, it
closes the contact between terminals 19 and 20.
System Pump Contact (Sys P1)
The Sys P1 output terminal (23) on the 667 is a powered output. When the relay in the
667 closes, 115 V (ac) is provided to the Sys P1 terminal (23) from the Power L terminal
(24). To operate the system pump, connect one side of the system pump circuit to
terminal 23 and the second side of the pump circuit to the neutral (N) side of the 115
V (ac) power supply.
System Pump Contact (System Pmp 2)
The System Pmp 2 terminals (17 and 18) are an isolated output in the 667. There is no
power available on these terminals from the control.
If the System Pmp 2 contact is used, connect the pump circuit to the System Pmp 2 terminals
(17 and 18).
Melting Contact
The Melting terminals (21 and 22) are an isolated output in the 667. There is no power
available on these terminals from the control. These terminals are used as a switch to
make or break an external circuit.
Variable Speed Injection Pump
The 667 can vary the speed of a permanent capacitor, impedance protected or equivalent
pump motor that has a locked rotor current of less than 2.4 A. Most small wet rotor
circulators are suitable as described in Essay E 021. The 667 has an internal overload
fuse which is rated at 2.5 A 250 V (ac). Contact your tekmar sales representative for
details on the repair procedures if the fuse is blown.
If a variable speed injection pump is used, connect one of the wires from the variable
speed injection pump to the Var terminal (1) on the 667. Connect the Com terminal (2) to the
live (L) side of the 115 V (ac) power source. The other wire on the variable speed injection
pump must be connected to the neutral (N) side of the 115 V (ac) power supply.
15 16
Melt / Idle
Demand
24 to 230 V (ac)
L
N
Boiler
20 19
Sys
P1
115 V (ac)
N
L
Power
25
L N
24 23
17 18
System
Pmp 2
115 V (ac)
L
N
1 2
Pwr
Mix
Var
115 V (ac)
N
L