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Your
Furnace
(Cont.)
CIRCULATING
AIR BLOWER
The blower
to circulate
room air through
the furnace
starts
as soon
as the internal.heater
in the Fan/Limit
control
causes
the fan switch
portion
to close com-
pleting
the electrical
circuit.
It shuts off when the Fan/Limit Control
opens the elec-
trical circuit.
This means the blower
comes
on approx-
imately
30 seconds
after the fu'rnace
first starts
and
it continues
to run unti] the furnace
cools down.
This
helps to achieve
the maximum
comfort
and efficien-
cy. from your
furnace.
FAN
RELAY
This relay provides
electric
power
to the Circulating
Air Blower
for
continuous
blower
operation
(Ther-
mostat
Fan Switch
set to "FAN
ON")
and for the
blower
to run if central .air conditioning
is installed.
FAN/LIMIT
CONTROL
The
Fan/Limit
Contro!
provides
power
to
the
Cir-
culating
Air Blower
to keep
it on, until
the
furnace
cools down.
The limit portion
provides
safety
because
it will open the low voltage
control
circuit,
shutting
the furnace
down
if it gets too hot.
The fan off setting
can be adjusted
if the fan remains
on long enough
that
cool drafts
are felt in the room
after the furnace
shuts
off.
Contact
a Qualified
Ser-
vice Technician.
DRAIN
TRAP
ASSEMBLY
The drain trap has a float
in it, that will cause
the fur-
nace
to
shut
down
if
the
drain
lines
become
obstructed.
If this happens
the trap and lines must be
taken
apart and cleaned.
See "Condensate
Disposal'"
page 10.
Thermostat
Your furnace
will not operate properly
without
a good
quality,
correctly
installed
thermostat.
The thermostat
location
is very
important
as it must
be sensing
average
room temperatures.
It must
not be exposed
to hot or cold drafts
or hot or cold spots
on the wall,
such as outside
walls
or a walt with
pipes
inside or
openings
into attic.
There are many
types
and styles
of thermostats
but
the operation is usually similar. BE SURE TO BECOME
FAMILIAR
WITH
YOUR THERMOSTAT,
The simplest
type
of thermostat
only starts and stops the furnace
to maintain
the proper room temperature.
The most
widely used types will control both heating and cool-
ing functions
and will have a Fan Switch
with Auto
and ON settings.
On Auto, the Circulating
Air Blower
will cycle on/off
with the furnace but if, switched
to
ON it will run constantly
whether
or not the furnace
is on.
In addition
there
are thermostats
that
automatically
switch
from
Heating
to Cooling
and with
night
set-
backs.
The night
set-back,
or multiple
set-back
type,
will lower the temperature
at night
or during
the day
when
no one is at home.
HEATING:
Posftion the Thermostat
System Switch
on HEAT, Set
the
Fan Switch
to AUTO
for
the blower
to cycle
ON/OFF.
Sefect desired
temperature
setting
and fur-
nace will automatically
start
up and shut off as re-
quired
to maintain
that
setting,
Fan Switch
may be
positioned
to ON for continuous
air circulation
only
if that position
maintains
the same or a higher blower
speed so you have the same or greater- airflow.
CAUTION
Continuous
Fan ON at too slow of a blower
speed may
cause
improper
furnace
operation
and
possible
damage to the heat exchanger,
HEATING
ANTICIPATOR:
For more precise comfort
control
your thermostat
may
have an adjustable Heat Anticipator.
(Some are not ad-
justable).
For most
homes
the anticipator
should
be
set on the value listed in the Tech
Data Sheet
which
is found
in the Furnace
Technical
Support
Manual.
If your furnace
cycles
ON/OFF
with
very short-ON
in-
tervals
or _f the
OFF cycle
is so long
that
room
temperatures
become
uncomfortable
the anticipator
setting
may need to be adjusted.
To Adjust:
Remove
thermostat
cover
and
locate
anticipator,
Check ,the setting.
!f not on.thesetting
recommen_
ed for your furnace,
moye
the lever to the proper set-'
ting and try it.for
a day or two,
To
lengthen
burner-on
time
move'
the
indicator
towards
"Longer"_
To decrease
burner-on
time move
in opposite
direction,
ira=
ii i
ii
NOTE
:
To accurately
determine
the effect
do not adjust
more
than
half a scale
marking
at a time
and
I
iI allow
a day between
adjustments.
I
ii
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II
II
III
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COOLING:
For cooling
simply
position
the
system
switch
to
COOL Instead
of HEAT and thermostat
will function
in the same manner
to control
cooling.
7
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