Installation & Operation Manual
5
Electrical connections
(continued)
37
Louver proving switch
1. When the operation of a louver proving switch needs
to be verified before the water heater fires, remove the
jumper wire from these terminals and connect them to the
normally open contacts on its proving switch (FIG. 5-4).
Water heater Management System (BMS)
1. An external control may be connected to control either the
firing rate or the set point of the appliance. Connect the 0 -
10 VDC terminals to the 0 - 10 VDC output of the external
control. The control can be programmed to use the enable
output of the Boiler Management System, or use the voltage
signal to enable the heater. Connect the enable terminals to
the enable output of the BMS, when used.
2. Make sure the ground terminal is connected to the ground
output terminal of the external control, and the 0 - 10 VDC
terminal is connected to the 0 - 10 VDC terminal of the
external control.
Runtime contacts
The control closes a set of dry contacts whenever the burner
is running. This is typically used by Building Management
Systems to verify that the water heater is responding to a call
for heat.
Alarm contacts
The control closes another set of contacts whenever the heater is
locked out or the power is turned off. This can be used to turn
on an alarm, or signal a Building Management System that the
water heater is down.
