CleaverBrooks CB120Z, Operation

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24 750-271
GETTING STARTED
The CB120Z System performs two main functions, burner management and boiler control. For
burner management, the CB120Z System continuously monitors interlocks and limits found in the
L1-13, L1-3 and 3-P circuits as it programs the burner/blower motor, ignition and fuel valves to pro-
vide for proper and safe burner operation. For boiler control, the CB120Z system continuously reads
the input pressure or temperature transducer, compares the reading to the appropriate user program-
mable setpoint, and adjusts the firing rate to meet output demand.
GENERAL INFORMATION
Once the sensor usage and range is selected and programmed, the user then programs the setpoints
associated with the operating control function of the CB120Z System. These setpoints are Steam
Pressure Setpoint (STM STPT) or Water Temperature Setpoint (WTR STPT), Cut In (CUT IN), and
Cut Out (CUT OUT) and Modulating Range (MOD RNG).
1.
CUT IN Setpoint is a differential value that is subtracted from the Setpoint to determine where
burner startup occurs.
2.
CUT OUT Setpoint is a differential value that is added to the Setpoint to determine where burner
shutdown occurs.
3.
MOD RNG Setpoint is a differential value that is subtracted from the Setpoint and determines
the range over which the firing motor will travel from high fire (100%) to low fire (0%). See
Figure 5.
This is an indication the mechanical limits (burner on switch, first low water cutoff, etc.) located in
the L1-3 operating control (recycling) circuit are closed but the burner is in a shutdown or standby
state due to the current measured primary control variable reading, pressure or temperature, is above
the cut in point.
ALL-INFO SCREEN
The CB120Z control provides all boiler control information as part of one display screen located in
the main CB120Z menu structure. From any burner operating position, the user can see the current
operating temperature or pressure, mod motor usage and firing range position, operating mode and
flame signal detected.
While in STANDBY or AUTO mode the ALL-INFO screen becomes the default screen, occurring
10 seconds after that state is reached.
Programming/Set-up Guide
Included with this bulletin is a Programming/Set-up guide see page 77 and page 78 to aid the user in
programming the control. The set-up sheet lists all of the setpoints associated with the CB120Z con-
trol. The set-up sheet is a valuable tool by providing an overview of what setpoints need to be pro-
grammed for the various functions, as well as providing a written copy of the setpoints to refer to
when actually programming the setpoints. It also serves as a permanent hard copy record.
The CB120Z requires the user to program a number of operating parameters for proper system oper-
ation. While the CB120Z Control offers a number of features and functions, a user can program four
STANDBY
L1-3 CLOSED
8.7P AUTO 36%
LEAD FLM 42
PRIMARY CONTROL VARIABLE
OPERATING MODE
MOD MOTOR USAGE
FIRING RATE
FLAME SIGNAL