2-12.3 Add Stage Method; 2-12.4 Drop Stage Method; System Integrator Display Wiring And Lead Lag Bus Wiring; 2-13.1 System Integrator Display Wiring - Ace Heating Solutions Atlas A050 Operating And Maintenance Manual

the slave's commanded firing rate. If at least one stage has been dropped, no stage is requested to exceed the
Common Base Load Rate.

2-12.3 Add Stage Method

Factory default setting for adding a stage is Error Threshold method. A stage is added when the error becomes
excessive based on the degrees away from setpoint and time. Add stage condition will occur when the
modulating slaves are at their maximum rate per the rate allocation rules (base load rate or maximum firing rate)
and header sensor is reading below the lead lag setpoint by amount greater than or equal to the Add Stage Error
Threshold (Default 5F). Condition will have to continue for Add Stage Interstate Delay (Default 30 seconds)
before stage can be added.

2-12.4 Drop Stage Method

Factory default setting for dropping stage is Rate Threshold. A drop stage condition will occur when the last
stage is at the minimum modulation rate. Condition will have to continue for Drop Stage Interstate Delay
(Default 30 seconds) before stage can be dropped.

2-13 System Integrator Display Wiring and Lead Lag Bus Wiring

2-13.1 System Integrator Display Wiring

System operator interface panel will be preassembled from the factory with the 12V power supply. Installer will
need to wire 120VAC and RS-485 communication connections.
Display communication is done over MB1 RS-485 bus on each boiler (MB1 A, B, and C Terminals on
Honeywell Controller). Daisy chain network wiring to MB1 terminals is required if display is used with
multiple boilers.
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