CHAPTERJ
• All applicable limits are correct for the
burner operation.
• The load demand light glows.
All entrance switches
are closed and the
power
is
present at the line terminals of:
-Blower
motor starter
-Air
compressor motor starter (if
provided)
-Oil
heater relay (if provided)
~il
pump motor starter
(if
provided)
These sequences do not attempt
to
correlate the
action
of
the fuel supply system
or
feedwater
system except for the interlock controls that
directly relate
to
the action
of
the program relay.
Chapters
4
a_nd
5 contain operating instructions
and specific information on setting and adjusting
the controls.
B.
CIRCUIT
AND
INTERLOCK
CONTROLS
The burner control circuit
is
a two-wire system
designed for 115 volt, single phase,
60Hz,
alter-
nating current.
The electrical portion
of
the boiler is made
up
of
individual circuits with controls that are wired in
a manner designed
to
provide a safe workable
system. The program relay provides connection
points for the interconnection
of
these various
circuits.
CHAPTER 3-6
SEQUENCE
OF
OPERATION
The controls used
vary
depending upon the fuel
- oil
or
gas - and the specific requirement
of
applicable regulatory bodies. Refer to the boiler
wiring diagram to determine the actual controls
provided. The circuits and controls normally
used
in these circuits are listed below and referred
to in the following sequence
of
operation.
Limit Circuit:
• Burner switch (BS)
•
Operating limit control
(OLC)-
pres-
sure
or
temperature
• High limit control (HLC) - pressure
or temperature
• Low water cut-off (LWCO)
•
Gas-oil selector switch (GOS) - (Com·
bination burner only)
• Oil drawer switch (ODS) - Oil burner
• Low oil temperature switch
(LOTS)-
(No. 5 and 6 oil only)
• Low gas pressure switch (LGPS)
• High gas pressure switch (HGPS)
•
Fuel Valve Interlock Circuit
• Main gas valve auxiliary switch
~GVAS)
Oil valve auxiliary switch (OV AS)
Blower Motor
Start
Circuit
• Blower motor starter (BMS)
Air compressor motor starter (ACMS)
(if provided)
Air purge valve (APV) (No.
5
or
6 oil
only)
750-150
To Next Page
Loading...
