Heat Demand - Weil-McLain BCP-3 Installation & Operating Instructions Manual

LEAD STAGE ROTATION
• For the single boiler and lo/hi boiler operating mode, when heat is required, the first stage brought on is Output 1 (see output
chart pg. 3).
• For the 2 and 3 boiler operating modes, the lead stage will rotate among the boilers to promote even wear on each unit.
• The Lead Stage will always be the first stage brought on when there is a call for output.
• As more output is needed, additional stages are added.
• When less output is needed, the additional stages are turned off in the reverse order of how they were added. For instance, if the
stages were added in the sequence 1, 2, and 3, then they will be turned off in the sequence 3, 2, and finally 1.
• On power-up, the lead boiler will always be Output 1.
• The Lead Stage will rotate every 24 hours (either between Output 1 and 2 for 2 boilers, or between Output 1, 2 and 3 for 3 boilers).
OUTPUT LIGHT DISPLAY
• The red LED marked OUTPUT indicates when the BCP-3 is in the heating mode.
• The red LED will be off when the outdoor temperature is above the Outdoor Starter, or when the HEAT DEMAND input is open.
• When the outdoor temperature is below the Outdoor Starter, and the HEAT DEMAND input is closed, the red LED will be on.

HEAT DEMAND

• When the HEAT DEMAND input terminals are open, the BCP-3 will not energize any stages.
• The BCP-3 comes equipped with a factory installed jumper across the HEAT DEMAND terminals. DO NOT remove this jumper
unless it is being replaced by a dry contact switch.
• This input would typically be provided by a thermostat. When the thermostat is satisfied, there is no need for heat. When the
thermostat requires heat, the BCP-3 will activate and stage the Outputs to hold the required set point.
• This input can also be used as a remote stop/start for the BCP-3.
• When the HEAT DEMAND terminals are first opened, all active boiler outputs will immediately turned off. However, the System
Pump output (not available in the 3 boiler operating mode) will continue to run on for 3 minutes before turning off.
SYSTEM PUMP OPERATION
• The System Pump output is design to continuously circulate the heating water whenever heat is required.
• The System Pump relay will energize whenever the outdoor temperature is below the Outdoor Starter temperature and the HEAT
DEMAND input is closed.
• When either the outdoor temperature rises above the Outdoor Starter, or the HEAT DEMAND input is opened, the System Pump
will run on for 3 more minutes. This removes heat from any boiler stages which were active and circulates it around the system.
• If the System Pump output has not been activated for 7 days (as might occur in the summer), the relay will be energized for 15
seconds to exercise the pump.
• The System Pump output not available in the 3 boiler operation mode.
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