Operating instructions
7
2 Stage (Lo/Hi) Units
(Refer to Chart below)
• Each unit has two relays and two OUTPUTS associated with it.
• Check the chart for the Lo and Hi stage output positions.
• Connect the Lo N.O. relay contacts in series with the unit’s limit circuit.
• Connect the Hi N.O. relay contacts to the Hi control circuit.
NO
C
Lo
Output
Limit
Circuit
NO
C
Hi
Output
Hi
Circuit
Typical Limit Circuit for
2 Stage Units
Refer to Specific Boiler Wiring Diagram
OUTPUT
SYSTEM
OUTPUT Number of Lo/Hi/Lo Boiler Units
1 2 3 4 5 6
Output
1
Lo
1
Lo
1
Lo
1
Lo
1
Lo
1
Lo
1
Output
2
Hi
1
Hi
1
Hi
1
Hi
1
Hi
1
Hi
1
Output
3
Lo
2
Lo
2
Lo
2
Lo
2
Lo
2
Output
4
Hi
2
Hi
2
Hi
2
Hi
2
Hi
2
Output
5
Lo
3
Lo
3
Lo
3
Lo
3
Output
6
Hi
3
Hi
3
Hi
3
Hi
3
Output
7
Lo
4
Lo
4
Lo
4
Output
8
Hi
4
Hi
4
Hi
4
Outpu
t 9
Lo
5
Lo
5
Output
10
Hi
5
Hi
5
Output
11
Lo
6
Output
12
Hi
6
System
* * * * * *
WIRING THE SYSTEM OUTPUT
Combustion Air Damper operation (Damper open prove switch must
be in boiler limit circuit)
• Dip switch 1 must be OFF.
• When the BCP-6/12 requires a stage to be active starting with all stages off the
SYSTEM relay is energized. Then the BCP-6/12 waits 30 seconds to give the damper
time to open.
• After the 30 second delay, the BCP-6/12 will bring on boiler stages as necessary to
hold either the computed water temperature or the set point.
• The SYSTEM output contact will remain active as long as any OUTPUT is active.
• After the last OUTPUT is turned off, the SYSTEM relay will remain energized for the
period of time set by the System Delay. If the System Delay is set to 0, the SYSTEM
relay will turn off immediately when the last stage turns off.
• The SYSTEM contact has a single pole double throw (SPDT) output.
• The SYSTEM contact can be used to control a damper or valve motor, or to energize
any equipment which should be active when any OUTPUT is active. It can also be
used as a signal to indicate when the BCP-6/12 has enabled one or more stages.
• The SPDT output is capable of switching 6A resistive at 120VAC.
When using a combustion air damper, damper open prove
switch(es) are required and must be in the limit circuit of the
boilers. Failure to follow this can cause severe personal injury,
death, or substantial property damage.
W A R N I N G
* System relay should always be installed.