CHAPTER3
SEQUENCE OF OPERATION
CHAPTER3
SEQUENCE
OF
OPERATION
General A
B.
c.
D.
Circuit and Interlock Controls
Sequence
of
Operation - Oil
or
Gas
Flame
Loss
Sequence
A.
GENERAL
This chapter outlines the electrical sequencing
of
various controls through the pre-purge, ignition,
run, and shutdown cycles
of
the burner.
The program relay establishes the sequence
of
operation and directs the
operat~on
of
all other
controls and components to provide an overall
operating sequence.
NOTE: The make
or
model
of
the pro-
gram relay provided will vary
depending upon
job
specifica-
tions. The following sequence
ap-
plies regardless
of
the make
or
model. Please refer to the Wiring
Diagram
(WD)
prepared
by
Oeaver-Brooks for your specific
installation.
In
the schematic type wiring diagram provided
for the boiler, the grounded (common) side
of
the
power supply
is
shown
as
a vertical line on the
right side
of
the diagram. All inductive com-
ponents (coils, solenoids, transformers, lights,
etc.) are connected to
it. The hot side
of
the power
supply
is
shown
as
a vertical line
on
the left side
of
the electrical schematic. All the inductive
750-150
components are connected to it through switches
or
contacts that permit the component to function
when required.
Abbreviations for the various electrical
com-
ponerits are listed in Figure 3-1. The sequences
outlined in this chapter employ these
designa-
tions
to
aid
in
applying the text to the wiring
diagram.
For an
explanatocy booklet on schematic wirlnlj
djaiWlms. reQuest
Cleaver-Brooks Bulletin C17-
4095
from
your Cleaver-Brooks local
repre-
sentative.
The burner and control system are in a starting
condition when the following conditions exist:
The boiler water is up to the correct
level closing the low water cut-off
switch.
• The low water
~ight
(panel)
is
off.
• The operating limit pressure control
(steam boiler)
or
the operating lim
it
temperature control (hot water boiler)
and high limit pressure
or
temperature
control are below their cut-off setting.
CHAPTER
3-1
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