MONITOR HEATING SYSTEM
Section
1:
Description
1-23
AIR
PRESSURE SWITCH
This
switch consists
of a
rubber diaphragm which
senses
changes
in air
pressure
(it is
connected
to
the
Combustion Blower
and the
Heat
Exchanger)
and
a
normally-open, micro switch.
Should
an
abnormal pressure differential
exist,
the
switch
opens
to
disable
the
circuitry that con-
trols
the
supply
of
gas. Since
the
flow
of gas to
the
Burner
is cut
off,
the
flame extinguishes,
and
the
code
[E17]
is
indicated
in the
digital dis-
play.
This
safety
mechanism
can be
triggered
by
several
conditions:
-
Leak, loose,
or
broken tubing which connects
the Air
Pressure Switch with
the
Combustion
Blower
or the
Heat Exchanger.
-
Clogged
or
blocked
Air
Line
-
Blocked
or
clogged Flue Pipe
-
Intake port
of the
Combustion Blower
is
blocked
-
Combustion Blower
is
inoperable
1-24
OVERHEAT
PROTECTOR
SWITCH
(GF3800)
The
normally-closed Overheat Protector
Switch
safeguards
the
heaters against damage
due to
overheating.
The
Switch
is
rated
115°C
(239°F).
Should
a
Monitor overheat
(internal
temperatures rise
be-
yond
115°C/239°F)
switch will open
to
shut
down
the
heater.
After
extinguishing
the
flame,
the
code
FE17J
is
indicated
in the
digital
display.
The
Overheat Protector Switch will automatically
reset
after cooling down. Once
the
heater
has
cooled
to
90°C
(194°F),
the
system
can be re-
started.
To
restart
the
Monitor, proceed
as
fol-
lows:
A.
Press
ON/OFF Switch
to
OFF.
B.
Allow heater
to
cool.
C.
Troubleshoot
the
cause
of the
overheat.
D.
Press ON/OFF switch
to ON.
E.
Proceed with normal operation.
1-25
THERMAL FUSE (GF3800)
Should
Overheat Protector Switch malfunction,
and the
heater
be
further
overheated,
the
.ther-
mal
fuse
(internal temperatures rise beyond
145
°C/293°F)
melts
and
prevent further overheating.
1-26
OVERCURRENT
FUSE
2-amp.,
125VAC,
fuse protects
the
heater from
damage
resulting
from power overloads.
In the
event
of a
power surge
or
internal wiring hazards,
the
fuse opens
and
power
to the
heater
is cut
off.
1-27 ELECTRICAL SYSTEM
Electrical power
is
supplied
to the
Monitor
to run
the
Microprocessor
and the
other
electrically-
energized component.
Electrical
operation
of the
Monitor
can be
thought
of
as
having
the
following eight(8) distinct
phases: plug
in;
turn
on;
pre-purge; ignition; pre-
combustion; heating; shutdown
and
post-purge.
1-28
MICROPROCESSOR
Principally consisting
of a
64-pin Integrated
Circuit,
the
Microprocessor provides safety
timings,
controls
relays
and
provides clock
and
thermostat functions
for the
Monitor heater.
1-29 TEMPERATURE SENSOR
The
sensor which
is
capable
of
sensing room
temperature
within
a
range
of
42°F
to
96°F,
can
be
left mounted
on the
back
of the
heater cabinet
or be
wall mounted.
Approximately
4
1
/
2
'
(about
140cm)
of
No.22
AWG
Wire
is
supplied with
the
sensor
to
facilitate wall
mounting
the
sensor
in a
favorable location.
1-30 SAFETY MECHANISMS
Several
safety mechanisms have been
built
into
the
Monitor
Heating
System. These devices
protect
the
user against personal injury, protect
the
heater against damage,
and
shutdown
the
heater
if a
malfunction
occurs.
1-31 CLOTH COVERED EXHAUST PIPE
Insulating
cloth
covers
are to be
placed
over
all
metal surfaces
of the
Exhaust Line
during
installation.
Since
combustion
by-products
are
vented
at
elevated
temperatures,
the
Exhaust
Pipe
will
become
hot
during
operation.
The
insulating
cloth covers protect
the
user from
bum
hazards
associated
with
accidental
contact
with
these heated metal surfaces. During installation
make sure that
all
Exhaust Lines
are
tight.
Do not
operate
the
heater
without
the
insulating
covers.
1-32
AIR
CIRCULATION
FAN
GUARD
This
guard
is an
integral
part
of the fan
assembly.
The
guard protects
the
user
agrainst
physical
injury which could occur from accidental contact
with
revolving
metal
fan
blade.
9
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