StyleCrest Installation Manual

17
Installation Example
Elevation: ...................................................5,000 feet
Type of Gas: ............................................ Natural Gas
Local Heating Value of Gas: ...............................750
Determine which natural gas table to use. From Table
10, (page 24), find 750 and follow down the column,
stop at the 5,000 feet row. The heating value listed is
LOW. Table 12, (page 24) will be used to determine
orifice size and verify manifold pressure.
Code or local jurisdiction. In Canada, the requirements for
high altitude are different and governed by CSA B149.1.
Always consult your local code authority.
This furnace is 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 1000 feet of altitude. For
example, the input needs to be reduced 8% at 2,000 feet,
12% at 3,000 feet and 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,
especially in high altitude areas, the local gas utility
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 11, (page 24) & Table 12, (page
24) contain the manifold pressure and orifice sizes to
use at various altitudes. Table 11 (HIGH) is for natural
gas installations with a heating value of more than 1,000
Btu per cubic foot and Table 12 (LOW) is for less than
1,000 Btu per cubic foot. To determine which table to use:
1. Consult the local utility for the local heating value at
your installation site.
2. From Table 10, (page 24), 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 11
or if it’s LOW, use Table 12. See Example.
After 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 Input Rate (page 19).
IMPORTANT NOTE:
Observe the action of the burners to make sure there
is no yellowing, lifting or flashback of the flame.
Conversion to Propane (LP) Gas
WARNING:
This 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 factory supplied
conversion parts. Failure to use the proper
conversion kit can cause fire, explosion, property
damage, carbon monoxide poisoning, personal
injury, or death.
WARNING:
Shut off the gas supply at the manual gas shutoff
valve, before disconnecting the electrical power.
A fire or explosion may result causing property
damage, personal injury or loss of life. Failure to
follow the safety warnings exactly could result in
serious injury, death or property damage.
WARNING:
To avoid electric shock, personal injury, or death,
turn off the electric power at the disconnect or the
main service panel before making any electrical
connections.
This furnace can be converted from factory-equipped
natural gas to liquid propane gas. Conversion of this valve
requires replacement of the burner orifice and flipping the
regulator cap to the side marked LP. The orifice required
for conversion is supplied with the furnace. See Figure 27.
For altitudes between 0 and 1,999 feet, use the factory
supplied LP orifice as shown in Table 6, (page 16).
Altitudes between 2,000 and 10,000 feet require the orifice
to be changed. Table 13, (page 24) lists the correct
orifice size and manifold pressure at different altitudes.
Atmospheric & Direct Ignition Furnaces
1. Follow the instructions in “How to Shut Off Gas - Direct
Ignition” on page 19.
2. Disconnect the gas pipe union and the electrical wires
connected to the gas valve.
3. Remove the gas valve assembly:
4. Remove screw(s) from gas valve bracket. Gas valve and
spud may be removed. Orifice is located at the end of
the spud.
5. Replace the main orifice with the L.P. gas orifice supplied
in the envelope located by the gas valve. Verify the
orifice size matches the nameplate or Table 6, (page
16).
6. Unscrew the pressure regulator cap and check for the
letters NAT or LP. See Figure 27 (page 15).
7. Invert the cap and tighten until snug.
8. Reassemble the burner assembly into the furnace.