Weil-McLain BCP-8S User Manual download pdf (Page 6)

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The BCP-8W has multiple operating modes that satisfy most hydronic systems. It can sequence stages to achieve an adjustable Set Point

or an Outdoor Reset Ratio. Moreover, when used with the 420MOD Interface it can accept a 4-20mA signal as a set point. The 420MOD

Interface must be purchased separately. This gives the BCP-8W the capability of being controlled remotely.

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by either closing the TSTAT input or opening the SHUTDOWN input, and when the outdoor temperature is below the Outdoor Cutoff, the

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BCP-8W will start calculating the Reaction Period. If after a full Reaction Time the control logic foresee additional stages are needed,

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When the BCP-8W PID logic foresees that the system will overshoot, regardless of the current system and target values, it will make sure

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satisfying the Minimum Runtime condition. That is, if the Set Point was 150°)DQGWKH/DVW6WDJH+ROGZDVVHWWR°F, the lead stage

ZLOOUHPDLQHQHUJL]HGXQWLOWKHV\VWHPUHDFKHV°F and a full Minimum Runtime elapses. This is useful in protecting the lead stages

from short cycling.

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setting, as a mean to calculate the number of stages the BCP-8W shall have on at any point. For every Throttle Range below the set

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As the system temperature rises towards the set point, stages will turn off. Using the previous example, when the system rise to 175°F

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point. This will leave the lead boiler A on until the temperature rises to 185°)WKHQWXUQRIIGHHQHUJL]H

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185°F

180 + (1)THR

--- None A None

180°F 180 - (0)THR --- None --- A

175°F 180 - (1)THR A A B A

171 to 174°F --- --- A --- A,B

170°F 180 - (2)THR B A,B C A,B

166 to 169°F --- --- A,B --- A,B,C

165°F 180 - (3)THR C A,B,C D A,B,C

161 to 165°F --- --- A,B,C --- A,B,C,D

160°F 180 - (4)THR D A,B,C,D --- A,B,C,D

1 2 3 4 5 6 7 8 9 10 11 ... 39 40

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Weil-McLain BCP-8S User Manual Page 6

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