Installation guide

66840/035-20003-001Rev.B(1205)
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, times 2 cubic ft. 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. of gas
from the gas meter.
For propane (LP) gas multiply the heat content of the gas BTU/SCF (or Default 2500 BTU/SCF, times ! cubic ft. 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 ! cubic
ft. of gas from the gas meter.
The formula for US input calculation using a cubic foot gas meter:
BTU/f 3 x 2 cult x 0960 x 3600 BTUH/H
Seconds it took to measure the 2 cu.ft, of gas
NATURAL GAS INPUT CALCULATION
EXAMPLE:
79,997.38
1030 x 2 x 0960 x 3600
905
Natural Gas
BTU/SCF 1030
I BTU/f 3 x 1 cu.ft, x 0.960 x 3600
Seconds it took to measure the 2 cuft of gas
PROPANE (LP) GAS INPUT CALCULATION
EXAMPLE:
2500 x 1 x 0960 x 3600
108
Propane Gas
BTU/SCF 2500
= BTUH/H
= 80,00000
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 MJ/m 3 (or Default 39.2), times 2 cu. ft. of gas x 0.02831 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 cu.ft, of gas from the gas meter.
For Propane (LP) Gas multiply the Heat content of the gas M Jim 3 (or Default 93.14), times ! cu. ft. of gas x 0.02831 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 ! cu.ft, of gas from the gas meter.
The formula for metric input calculation using a cubic foot gas meter:
MJ/m 3 x (2 cu.ft, x Cony) x 0960 x 3600
= MJ/H
Seconds it took to measure the 2 cu ft of gas
NATURAL GAS INPUT CALCULATION
EXAMPLE:
392 x 2 x 0.960 x 3600
= 8476
90.5
Natural Gas
BTU/SCF 1030 = 39.2 MJ/m 3
PROPANE (LP) GAS INPUT CALCULATION
EXAMPLE:
9315 x 1 x 0960 x 3600
= 8441
108
Propane Gas
BTU/SCF 2500+93 15 MJ/m 3
02777 kW x 3412.14 BTUH/H
02777 2354 x 3412.14 80,31262
02777 2345 x 3412.14 80,00000
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 3gas MJim (or Default 39.2), times 0.0566 m 3of 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 0.0566 m3 of gas from the gas meter.
For Propane (LP) Gas multiply the Heat content of the gas M Jim 3 (or Default 93.14), times 0.00283 m3 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 0.0283 cm of gas from the
gas meter.
The formula for metric input calculation using a cubic foot gas meter:
MJ/m 3 x (2 cu.ft, x Cony) x 0960 x 3600
= MJ/H
Seconds it took to measure the 2 cu ft of gas
NATURAL GAS INPUT CALCULATION
EXAMPLE:
392 x 2 x 0.960 x 3600
= 8476
90.5
Natural Gas
BTU/SCF 1030 = 39.2 MJ/m 3
PROPANE (LP) GAS INPUT CALCULATION
EXAMPLE:
9315 x 1 x 0960 x 3600
= 8441
108
Propane Gas
BTU/SCF 2580+93 15 MJ/m 3
02777 kW x 3412.14 BTUH/H
02777 2354 x 3412.14 80,31262
02777 2345 x 3412.14 80,00000
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 orifice spuds with the gas ori-
fice spuds 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 Unitary Products Group