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BCP-3 Installation and Operation Manual
Mounting the Controller
• The BCP-3 is designed to mount on a 1900 (4”x4”) deep
electrical box.
• If additional room is needed for wiring use the extension
skirt provided.
• Place the BCP-3 in an indoor convenient location near
the unit to be controlled and away from excessive heat
or cold.
• Partially unscrew the Display Cover Mounting screws.
This allows for its removal.
• Lifting the Display Section away from the base starting
with the bottom will unplug it from the Base section.
• Proceed with the power and output wiring instructions.
• Use the screws provided to mount the BCP-3 to the
1900 box or the extension skirt.
• Mount Display Section back to the Base Section.
Tighten the Display Cover Mounting Screws.
Wiring
Wiring Power Input
The BCP-3 is designed to accept ONLY A SINGLE POWER SOURCE. It can be wired to
either 120VAC using the two Black wires or 24VAC using the right most two terminals on the
terminal block on bottom of the control. Weil McLain recommends the installation of a Surge
Suppressor and a Power Switch before the Power Line connection for safety and ease of service.
120VAC
• Attach line voltage, 120VAC, to the two Black wires extending from the back of the BCP-3.
Remember to use the power line from a different source than the equipment being controlled.
24VAC
• Use a dedicated transformer with at least a 5VA output.
• Bring 24VAC to the two right most terminals on the front of the BCP-3 marked 24VAC and
COM.
Wiring Input Terminals
Heating System Sensor (HSS) Installation (T1, COM)
Locating HSS
• Place the Heating System sensor in the common header where it will register the output of the
boilers before any takeoffs.
• Only use the Standard Brass Tube sensor provided.
• The sensor wires can be extended up to 500' using a shielded 2-conductor cable (Belden #8760 or
equivalent (#18/2)).
• Cut the shield and do not connect it at the sensor end. Only connect it at the control end using the outdoor
terminal marked COM. Do not ground the shield at the sensor but at the control using the COM terminal.
• Do not run sensor wires in conduit with line voltage wiring.
Immersion Heating System Sensor (HSS) Installation
• Install a 3/8"ID x 1/2"NPT immersion well.
• Insert the supplied sensor probe into the well.
Strap-On Heating System Sensor (HSS) Installation
• Strap the sensor to the pipe using a metal clamps. Do not over tighten the clamp.
• Strap pipe insulation around the sensor and the pipe.
WARNING
The BCP-3 can accept only one source of power:
120VAC or 24VAC. If more than one power source is
applied, the unit may be damaged.
T1 T2 T3+
COM COM
T3-
EXT+ EXT-
P+ P-
COM24VAC
Display Cover Mounting Screws
Display SectionBase Section
Base Mounting Holes
Input Terminals 24VAC optional power input
120VAC Power Wiring
120VAC Power Source
BLACK
BLACK
E
XT+EXT-
P+ P-
COM 24VAC
24VAC Power Source
24VAC
Comm
24VAC Power Wiring
T1 T2 T3+
COM COM
T3-
EXT+ EXT-
P+ P-
COM 24VAC
Input Terminals
System Sensors
{
Enable/Disbale Input
Dry-Contact
{
{
Outdoor Sensor
{
24VAC power Input
{
DHW Input Dry-Contact
Setback Input Dry-Contact
{
T1 T2 T3+
COM COM
T
Shield
Shield
System Temp
Outdoor Sensor
Sensor Wiring