Installation guide
129098-UIM-H-1011
In
the
USA
use
the
following
formula
to
calculate
the
furnace
input.
For
natural
gas
multiply
the
heat
content
of
the
gas
BTU/SCF
or
Default
1030
BTU/SCF
(38.4
Mu/m?),
times
2
cubic
ft.
(0.056
m)
of
gas
measured
at
the
gas
meter,
times
a
barometric
pressure
and
temperature
correction
factor
of
0.960;
times
3600,
then
divided
by
the
time
(In
seconds)
it
took
to
measure
2
cubic
ft.
(0.056
m)
of
gas
from
the
gas
meter.
For
propane
(LP)
gas
multiply
the
heat
content
of
the
gas
BTU/SCF
or
Default
2500
BTU/SCF
(93.15
Md/m?),
times
1
cubic
ft.
(0.028
m)
of
gas
mea-
sured
at
the
gas
meter,
times
a
barometric pressure
and
temperature
correction
factor
of
0.960;
times
3600,
then
divided
by the
time
(In
seconds)
it
took
to
measure
1
cubic
ft.
(0.028
m)
of
gas
from
the
gas
meter.
The
formula
for
US
input
calculation
using
a
cubic
foot
gas
meter:
BTU/tt?
x 2
cu.ft.
x
0.960
x
3600
=
BTU/H
BTU/stt®
x
1
cu-ft.
x
0.960
x
3600
=
BTU/H
Seconds
it
took
to
measure
the
2
cu.ft.
of
gas
Seconds
it
took
to
measure
the
1
cu.ft.
of
gas
NATURAL
GAS
INPUT
CALCULATION
PROPANE
(LP)
GAS
INPUT
CALCULATION
EXAMPLE: EXAMPLE:
1030
x 2 x
0.960
x
3600
-
78,666.90
2500
x
1
x
0.960
x
3600
-
80,000.00
90.5
708
Natural
Gas
Propane
Gas
1030
BTU/SCF
2500
BTU/SCF
In
Canada
you
will
use
the
following
formula
to
calculate
the
furnace
input
if
you
are
using
a
cubic
foot
gas
meter.
For
Natural
Gas
multiply
the
Heat
content
of
the
gas
Mu/m3
(or
Default
38.4),
times
2
cubic
ft.
of
gas
x
0.028
to
convert
from
cubic
feet
to
cubic
meters
measured
at
the
gas
meter,
times
a
barometric
pressure
and
temperature
correction
factor
of
0.960;
times
3600,
then
divided
by
the
time
it
took
to
measure
2
cubic
ft.
(0.056
m)
of
gas
from
the
gas
meter.
For
Propane
(LP)
Gas
multiply
the
Heat
content
of
the
gas
Mim?
(or
Default
93.15),
times
1
cu.
ft.
of
gas
x
0.028
to
convert
from
cubic
feet
to
cubic
meters
measured
at
the
gas
meter,
times
a
barometric
pressure
and
temperature
correction
factor
of
0.960;
times
3600,
then
divided
by
the
time
it
took
to
measure
1
cubic
ft.
(0.028
m)
of
gas
from
the
gas
meter.
The
formula
for
metric
input
calculation
using
a
cubic
foot
gas
meter:
Muim?
x
2
cu.ft.
x
0.028
x
0.960
x
3600
=
MJ/H
x
0.2777
Seconds
it
took
to
measure
the
2
cu.ft.
of
gas
NATURAL
GAS
INPUT
CALCULATION
EXAMPLE:
38.4
x
2
x
0.028
x
0.960
x
3600
90.5
kw
x
3412.14
=
BTU/H
=
82.12
x
0.2777
22.80
x
3412.14
=
77,796.80
Natural
Gas
1030
BTU/SCF
=
38.4
Mu/m®
PROPANE
(LP)
GAS
INPUT
CALCULATION
EXAMPLE:
93.15
x
1
x
0.028
x
0.960
x
3600
708
=
83.46
x
0.2777
23.18
x
3412.14
=
79,093.4
Propane
Gas
2500
BTU/SCF
=
93.15
Mu/m®
In
Canada
use
the
following
formula
to
calculate
the
furnace
input
if
you
are
using
a
gas
meter
that
measures
cubic
meters.
For
Natural
Gas
multiply
the
Heat
content
of
the
gas
Mim?
(or
Default
38.4),
times
0.10
m?
of
gas
measured
at
the
gas
meter,
times
a
barometric
pressure
and
temperature
correction
factor
of
0.960;
times 3600,
then
divided
by
the
time
it
took
to
measure
0.10
m?
of
gas
from
the
gas
meter.
For
Propane
(LP)
Gas
multiply
the
Heat
content
of
the
gas
Mdm?
(or
Default
93.15),
times
0.10
m?
of
gas
measured
at
the
gas
meter,
times
a
baro-
metric
pressure
and
temperature
correction
factor
of
0.960;
times
3600,
then
divided
by
the
time
it
took
to
measure
0.10
m?
of
gas
from
the
gas
meter.
The
formula
for
metric
input
calculation
using
a
cubic
meter
gas
meter:
Muim®
x
m®
x
0.960
x
3600
Seconds
it
took
to
measure
the
0.10
Mm
of
gas
NATURAL
GAS
INPUT
CALCULATION
EXAMPLE:
38.4
x
0.1
x
0.960
x
3600
160
=
MJ/H
x
0.2777
kw
x
3412.14
=
BTU/H
82.94
x
O2777
=
23.03
x
3412.14
=
78,581.60
Natural
Gas
1030
BTU/SCF
=
38.4
Mu/m?
PROPANE
(LP)
GAS
INPUT
CALCULATION
EXAMPLE:
93.15
x
0.1
x
0.960
x
3600
387
83.19
x
O2777
=
23.10
x
3412.14
=
78,826.3
Propane
Gas
2500
BTU/SCF
=
93.15
Mu/m®
DO
NOT
ADJUST
the
manifold
pressure
regulator
if
the
actual
input
is
equal
to
or
within
8%
less
than
the
furnace
input
specified
on the
rating
plate
or
if
the
furnace
rise
is
above
the
specified
rise
range
on
the
rating
plate.
If
the
actual
input
is
significantly
higher
than
the
furnace
input
specified
on
the
rating
plate
then
replace
the
gas
orifices
with
the
gas
orifices
of
the
proper
size
for
the
type
of
gas
you
are
using.
For
altitudes
above
2,000
ft.
(610
m)
the
furnace
input
MUST
BE
DERATED.
Refer
to
the
GAS
CONVERSION
FOR
PROPANE
(LP)
AND
HIGH
ALTITUDES
IN
SECTION
IV
for
information
on
high
altitude
conversions.
22
Johnson
Controls
Unitary
Products