J962V Installation Manual

19
High Altitude Application (Natural Gas Only)
The installation of this furnace at altitudes above 2,000
feet must meet the requirements of the National Fuel Gas
Code or local jurisdiction. In Canada, the requirements for
high altitude are different and governed by CGA B149.1.
Please consult your local code authority.
WARNING:
The reduction of input rating necessary for high
altitude installation may only be accomplished
with factory supplied orifices. Do not attempt to
drill out orifices in the field. Improperly drilled
orifices may cause fire, explosion, carbon
monoxide poisoning, personal injury or death.
The furnaces are shipped from the factory with orifices
and gas regulator settings for natural gas operation at sea
level altitudes. At 2,000 feet, the NFGC requires that this
appliance be derated 4% for each 1,000 feet of altitude.
For example, the input needs to be reduced 8% at 2,000
feet, 12% at 3,000 feet, etc. This deration is in reference
to the input rate and gas heating value at sea level.
To derate the furnace requires knowing the heating value of
the gas at the installation site. Heating values at particular
job sites vary for two reasons:
1. The chemical mixture of the gas varies from region to
region and is expressed as the “sea level heating value”.
2. The heating value varies by altitude. For this reason,
particularly in high altitude areas, the local gas utility
usually specifies the heating value at the residence’s
gas meter as the “local value”.
For added flexibility, two tables have been provided for
natural gas installations with high or low heating values
at sea level. Table 10 (page 29) & Table 11 (page 29)
contain the orifice sizes and manifold pressure to use
at various altitudes. Table 10 (HIGH) is for natural gas
installations with a heating value of more than 1,000 Btu
per cubic foot and Table 11 (LOW) is for less than 1,000
Btu per cubic foot. To determine which table to use:
1. Consult your local utility for the local heating value at
your installation.
2. From Table 9 (page 28), find your local heating value
as supplied by the utility company. Follow down the
column and stop at your altitude level.
3. If your sea level heating value is HIGH, use Table 10 or
if it’s LOW, use Table 11. See example.
EXAMPLE
Elevation: .................................................. 5,000 feet
Type of Gas: ........................................... Natural Gas
Local Heating Value of Gas: .............................. 750
From
Table 9, find 750 and follow down the column,
stop at the 5,000 feet row. The heating value listed is
LOW. Table 11 will be used to determine orifice size
and manifold pressure.
After changing the regulator pressure or changing the
orifices, it is required that you measure the gas input rate.
This may be accomplished in the usual way, by clocking
the gas meter and using the local gas heating value. See
Verifying & Adjusting the Input Rate section (page 23).
IMPORTANT NOTE
Observe the action of the burners to make sure there
is no yellowing, lifting or flashback of the flame.
For US installations only: To avoid nuisance tripping
at altitudes from 7500 to 10,000 feet, a pressure switch
conversion may be required. Consult the tables in the LP
and High altitude and LP gas conversion kit for installations
in the US.
Converting from Natural Gas to LP / Propane
WARNING:
The furnace was shipped from the factory
equipped to operate on natural gas. Conversion
to LP / Propane gas must be performed by
qualified service personnel using a factory
supplied conversion kit. Failure to use the proper
conversion kit can cause fire, explosion, property
damage, carbon monoxide poisoning, personal
injury, or death.
Conversion to LP / Propane is detailed in the installation
instructions provided with the conversion kit. Generally,
this will require the replacement of the burner orifices and
the spring assembly in the pressure regulator. Approved
conversion kits are listed below:
• Installations in the United States: For Propane (LP)
conversion or for LP gas installations in altitudes between
2,000 ft. and 10,000 ft. above sea level, use the LP &
High Altitude LP Gas Conversion Kit (P/N 905028) for
Installations in the United States. Please follow the
instructions provided with the kit.
• Installations in Canada: For Propane (LP) conversion or
for LP Gas installations in altitudes between zero and
4,500 ft. above sea level, use the LP & High Altitude
LP Gas Conversion Kit (P/N 905029) for Installations
in Canada. Please follow the instructions provided
with the kit.
If the installation is in the U.S. above 2,000 ft., refer to
Table 8 (page 28) to determine the correct orifice size
and regulator pressure. See Example below.
EXAMPLE
Elevation: .................................................. 5,000 feet
Type of Gas: .........................................Propane Gas
Input BTUH of Furnace: ................................80,000
From
Table 8, find 5,000 and follow across the row; stop
at the 80,000 btuh column. At first stage, the manifold
pressure listed is 4.2, but at 2nd stage the pressure is
9.0. The listed orifice size is 56.
When conversion is complete, verify the manifold pressure
and input rate are correct as listed in the Tables.