Bryant 394U - Checking Furnace Controls and Operation

Light
Main
Burners
using
the
procedure
contained
on
the
metal
Lighting
Instruction
Plate
ΕΕ
to
the
front
of
the
furnace.
E
Adi
just
Gas
Rate.
Set
the
room
thermostat
on
call
for
‘heat
and
adjust
the
gas
rate.
There
will
be
approx-
imately
30
seconds
delay
before
the
valve
opens.
l.
City
Gases
—
Measure
gas
input
at
the
meter.
The
burners
are
equipped
with
fixed
Orifices,
sized
to
produce
the
rated
input
shown
on
the
rating
plate.
Ἡ
measured
and
rated
input
are
not
approximately
the
same,
the
gas
piense
regulator
may
be
ad-
justed
as
follows:
a.
To
increase
input:
Turn
gas
pressure
regulator
|
adjusting
screw
‘clockwise.’
(Adjusting
screw
is
-
concealed
under
the
regulator
sealing
cap.)
b. To decrease input: Turn the adjusting Screw
!
‘counter-clockwise.’
The
manifold
pressure
should
be set as follows:
Natural Gas — 3 inches w.c.
Maximum pressure departure from recommended pres-
sure should be plus or minus 0.3 inches w.c.
2. Propane Gas — These units are not equipped with
gas pressure regulators. Burner orifices are sized
to give the rated input at a manifold pressure of
11 inches w.c. Since meters are not normally used
with propane gas, it will be necessary in most cases
to check the manifold pressure and adjust the regu-
lator at the supply tank to provide a pressure of
1 inches w.c.
3. If the input in item (1) or (2) above is too great
or too little, install new orifices. Be sure the rated
input is obtained without any. ΠΕ ΝΕ in
manifold gas poem LA M |
Adiust
Main
Bond
Plame:
M
“The:
main’
ac:
flame
.
Should
be
clear
blue,
almost
transparent,
with
a
well-
defined
inner
cone.
If
there
is
insufficient
primary
air,
the
flame
will
be
yellow-tipped.
If
there
is
too
p
much
primary
air
the
flame
will
be
well-defined,
but
with
a
tendency
to
dance
or
lift
off
the
burner
ports.
Ἱ.
Allow
furnace
to
operate
15
minutes.
2.
Adjust
each
burner
by
closing
the
air
shutter
until
a
slight
yellow
tip
appears
on
the
flame;
then
open
the
air
shutter
just
enough
to
clear
the
yellow
from
the
flame.
- I1-
- CHECK CONTROLS
Bryant
Diaphragm
Gas
Control
Valve
—
if
not
already
checked
when
lighting
the
main
burner,
check
the
proper
operation
of
this
valve
by
moving
the
room
thermostat
pointer
above
and
below
room
temperature
and
observe
that
the
main
burners
light
on
call
for
heat
and
go
off
when
the
pointer
is
moved
below
the
room
temperature
setting.
Remember,
there
will
be
approximately a 30 second delay on ignition and .
extinction.
Automatic
Pilot
—
To
check
the
pilot
operation
follow
the
instructions
below:
I. Set the room thermostat on call for heat.
There
is
a
delay
before
burners
light.
2. After burners have lit, close the pilot gas valve.
3. The automatic pilot will break the electrical
circuit
to
the
gas
valve
and
the
burners
will
shut
off. There is a delay before burners shut off.
Limit
Control
—
This
control
functions
to
shut
off
the
gas
if
the
furnace
becomes
over-heated..
The
method
of
checking
satisfactory
operation
is
left
to
-
the discretion of the installer. Extreme caution
should always. be employed. ME
Blower
Adjustmerit
—
lt
is
ρθρα
that
the
blower
speed
be
adjusted
before.
there
is
any
ΗΕ
to
adjust the fan control switch.
The
blower
speed
is
set
at
the
factory.
‘Under
no
circumstances
should
the
temperature
rise
across
the
furnace
be
allowed
to
exceed
105
degrees
F
After the desired air flow or temperature rise across
the furnace. has. been obtained, . the AMOR
Should be complete. |
Bryant has introduced a new concept in n controls
in the 394 furnace.
The 394 incorporates the tried and proven 822 Relay
for fan control. The 822 has a field adjustable dif-
ferential. The ‘‘max off” setting on the dial is for
the
longest
''off'
time
and
shortest
‘‘on’’
time.
. 394U