Weil-McLain BCP-3 Installation And Operation Instructions Manual
Weil-McLain BCP-3 Installation And Operation Instructions Manual

Weil-McLain BCP-3 Installation And Operation Instructions Manual

Hydronic multi-stage boiler control

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INSTALLATION AND OPERATION INSTRUCTIONS
Hot Water Control with
Outdoor Reset, Set
Point, and DHW for
Hydronic Applications
2 Line Alphanumeric Display
Displays sensor values and
menu settings
BCP-3
SYSTEM =
TARGET =
Boiler
Pump
Output 1
Output 2 Output 3
SET
SET
Display Section Locking Screws
This Weil McLain control is strictly an operating control; it should never be used as a
WARNING
primary limit or safety control. All equipment must have its own certified limit and safety
controls required by local codes. The installer must verify proper operation and correct any
safety problems prior to the installation of this Weil McLain control.
Black (120VAC power)
Output Lights indicate
output status
147F
150F
SYS
DHW
Pump
BCP-3
Hydronic Multi-Stage Boiler Control
The BCP-3 is a multi-boiler or multi-stage outdoor reset
hydronic heating control. It establishes ambient comfort by
varying the temperature of the heating system's circulating
hot water in response to changes in the outdoor temperature.
In addition, it provides an outdoor temperature based cutoff,
heating system pump control, and domestic hot water (DHW)
pump control. Two unique features have been added to this
control including a customized reset ratio curve. A Set Point
option was added for applications where outdoor reset will not
apply.
Two sensors are used, one to monitor the outdoor temperature
and one to monitor the circulating hot water temperature in
the heating system. When the outdoor temperature falls below
the outdoor cutoff setting, the heating system is activated
and the target water temperature is increased proportionally
to satisfy the load. Should it get warmer outdoors, the target
water temperature is automatically lowered by the control. If
the outdoor temperature continues to rise to the outdoor cutoff
setting then the heating system is turned off.
Because of the many different physical characteristics of
buildings including the type of radiation; i.e., baseboard or
radiant, the heat loss varies. In one building, a 1-degree
outdoors temperature change may require a change of 1 degree
in heating water temperature; for another it may require a
change of 2, 3, or even 4 degrees in order to gain the desired
comfort level. This is known as the Reset Ratio. The Reset
Ratio chart shows the wide range of Reset Ratios available for
the BCP-3 in addition to the customized reset ratio. See page 2.
Yellow (Output 1)
The installer fits the BCP-3 to a specific building by adjusting
the Reset Ratio curve. With curve number 4 (2:1 reset ratio)
a 2-degree change in outdoor temperature will change the
circulating hot water temperature by 1 degree; at curve number
Blue (Output 2)
11(1:3 reset ratio) an outdoor change of 1 degree will change
the water temperature by 3 degrees. Most buildings with
baseboard radiation require a curve of 6, 7, or 8. Radiant heat
White (Output 3)
applications usually require a lower curve. An external T-Stat
input can be used to shut the heating system down when the

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Summary of Contents for Weil-McLain BCP-3

  • Page 1 This is known as the Reset Ratio. The Reset Ratio chart shows the wide range of Reset Ratios available for the BCP-3 in addition to the customized reset ratio. See page 2. The installer fits the BCP-3 to a specific building by adjusting the Reset Ratio curve.
  • Page 2: Operation Concept

    System temperature exceeds the Target, the boiler relay will de-energize. • If sequencing multiple stages or boilers are the primary function of the BCP-3, the BCP-3 will use the Purge Delay to start the lead boiler. Then, it will use the Reaction Time to add additional stages or boilers. When subtracting stages, the BCP-3 will use only the Minimum Run Time.
  • Page 3: Mounting The Controller

    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...
  • Page 4: Wiring Outputs

    • No outputs will be active unless the EXT terminals are closed/shorted. Wiring the Setback/Boost (P+, P-) • The Setback feature can be used to provide the BCP-3 with a lower temperature Set Point when less heat is required during night or unoccupied periods. •...
  • Page 5 If any of the "1-On/Off" Output Modes is selected, wire the two Blue wires to the boiler circuit. • If more than one On/Off boiler is to be controlled by the BCP-3, follow the wiring colors as per the Output Mode Table above.
  • Page 6 (Yellow/Output 1) System Pump 120 VAC Power (Black) NOTES: • The BCP-3 does not source any output power Boiler 3 to any of its relays. A power source must sup- (White/ Output 3) ply the pumps with power and the control can break the hot leg.
  • Page 7: Operating Menu

    Sys. Trim +0 F Out. Trim +0 F <Back> Outdoor Trim: +0 F System Trim: +0 F Setback: 20 F Boost: BCP-3 Installation and Operation Manual Menus BCP-3 Loading Default Values... Boiler Control -OUTPUT MODE-- 1-On/Off+1-Pump 1-On/Off+2-Pump 2-On/Off+1-Pump 1-Lo/Hi+1-Pump 3-On/Off...
  • Page 8: Startup Options

    Options: 1-On/Off+1-Pump, 1-On/Off+2-Pump, 2-On/Off+1-Pump, 3-On/Off /<System Startup>/Display Unit/Control Mode/Output Mode • The new BCP-3 has multiple operating Output Modes of heating. Each can be applied based on the number of boilers, stages, and pumps controlled. See Output Mode Table on page 4. Sensor Fault Options: Output On, Output Off /<System Startup>/.../Sensor Fault...
  • Page 9: Default Display

    When Output-Off is selected, the BCP-3 will turn all boilers Off when the System sensor reads SHORT or OPEN. However, • when the Outdoor sensor reads SHORT or OPEN, the BCP-3 will change the Target Set Point to be the Min Water Temperature. Set Point Mode When Output On is selected, the BCP-3 will turn all boilers On when the System sensor reads SHORT or OPEN.
  • Page 10 When the outdoor temperature falls to the adjustable Outdoor Cutoff temperature, the BCP-3 will control the System Pump and Boiler relays to provide heat. • When the outdoor temperature rises to the Outdoor Cutoff plus a 2°F differential, the BCP-3 will turn the boilers off. The System relay will remain energized for the Run-On delay then de-energize. •...
  • Page 11 The Minimum Target Temperature must be set to the boiler manufacturer’s specification. The BCP-3 will calculate the Target based on the Outdoor temperature, the Reset Ratio, and the Offset value. The BCP-3 will control the boiler to hold the higher of either the calculated temperature or the Minimum Target Temperature.
  • Page 12 BCP-3 Installation and Operation Manual Minimum Runtime Options: 1 to 60 minutes /<Settings>/<Stage>/Min. Runtime • This is the minimum amount of time any stage will run. • The Minimum Runtime for the lowest firing stage on a boiler starts after the purge cycle.
  • Page 13 Options: From 0ºF/0ºC to 80ºF/44ºC /Settings>/Setback. • The Setback feature can be used to provide the BCP-3 with a lower temperature Set Point when less heat is required by closing the P+ and P- terminals. • The lower Set Point will appear on the main display indicating •...
  • Page 14: Troubleshooting

    Test for continuity across the pair of Yellow wires. If the wires are continuous, the BCP-3 is calling for the Heating System Pump to run and the problem is not with the BCP-3. Check the power source to the pump and the pump to determine why it is not circulating.
  • Page 15 Piping 1 On/Off Boiler + System Pump + DHW Pump NOTES: • The BCP-3 does not source any output power to any of its relays. A power source must supply pumps with power and the control can break the hot leg.
  • Page 16: Specifications

    BCP-3 Installation and Operation Manual Specifications Voltage Input: ..120 VAC 60 Hz(2 Black wires) /24VAC 60 Hz (24VAc terminals) (Only One Power Source) Power Consumption: ..........3 VA Max Operating Temperature: .

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