provided, it will require manual reset and the
initial low-water cutoff will not require manual
reset.
**************************************************************************
Combustion safety controls and equipment shall be UL listed,
microprocessor-based distributed process controller. The system shall
include mounting hardware, wiring and cables, and associated equipment.
The controller shall be mounted completely wired, programmed, debugged, and
tested to perform all of its functions. The controller shall process the
signals for complete control and monitoring of the boiler. This shall
include maintaining boiler status, starting and stopping all control
functions, sequencing control functions and signaling alarm conditions.
The program shall be documented and include cross references in description
of coils and contacts. Microprocessor shall be able to perform self
diagnostics and contain a message center to provide operator with status
and failure mode information. Controllers for each boiler shall be mounted
on a separate, free standing panel adjacent to the boiler or for packaged
boilers on the boiler supporting structure. Control systems and safety
devices for automatically fired boilers shall conform to ASME CSD-1.
Electrical combustion and safety controls shall be rated at 120 volts,
single phase, 60 Hz and shall be connected as specified in Section 16402
INTERIOR DISTRIBUTION SYSTEM. A 100 mm 4 inch diameter alarm bell shall be
provided and shall be located where indicated or directed. The alarm bell
shall ring when the boiler is shut down by any safety control or interlock.
Indicating lights shall be provided on the control panel. A red light
shall indicate flame failure, and a green light shall indicate that the
main fuel valve is open. The following shutdown conditions shall require a
manual reset before the boiler can automatically recycle:
a.
Flame failure.
b.
Failure to establish pilot flame.
c.
Failure to establish main flame.
d.
[Low-water] [supplementary low-water] cutoff.
e.
[High temperature cutoff] [High pressure cutoff].
2.3.7.1
Low-water Cutoff
**************************************************************************
NOTE: If state or local codes or regulations
require a second cutoff, a separate supplementary
low-water cutoff of the float type or electrode type
may be provided. Delete supplementary low-water
cutoff, if second cutoff is not required. Delete
feedwater regulator and pump controller for water
**************************************************************************
Low water cutoff shall be float actuated switch or electrically actuated
probe type low-water cutoff. Float chamber shall be provided with a
blow-down connection. Cutoff shall cause a safety shutdown and sound an
alarm when the boiler water level drops below a safe minimum level. A
safety shutdown due to low water shall require manual reset before
operation can be resumed and shall prevent recycling of the burner. The
cutoff shall be in strict accordance to the latest version of code,ASME
SECTION 15569A
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