47
LP
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ion
GAS VALVE
This furnace has a 24-volt gas valve. It has ports for
measuring supply and manifold gas pressure. The valve
body contains a pressure regulator to maintain proper
manifold gas pressure.
A control switch is on the valve body. It can be set to only
the
“ON”
or
“OFF”
positions. The gas valve is a slow-
opening valve. See Figure 32.
When energized, it takes 2 to 3 seconds to fully open.
1.
LP TANKS FROM LOCAL LP SUPPLIER MUST NOT
BE USED TO STORE ANYTHING (SUCH AS FER-
TILIZER) EXCEPT LP GAS. THIS INCLUDES ALL
DELIVERY VESSELS (LP TRUCKS). IF MATERIAL
OTHER THAN LP GAS IS USED IN THE SAME VES-
SELS/TANK AS THE LP GAS, THE LP GAS CAN
BECOME CONTAMINATED AND DAMAGE THE
FURNACE. THIS WILL VOID THE MANUFAC-
TURER’S WARRANTY. CONTACT THE SUPPLIER
TO MAKE SURE FERTILIZER IS NOT USED IN THE
SAME TANKS USED TO STORE AND DELIVER LP
GAS.
2.
NOTE:
Order the correct LP conversion kit from the
furnace manufacturer. Furnace conversion to LP gas
must be performed by a qualified installer, service
agency or the gas supplier.
3. All 34
90+ Modulating Gas Furnaces installed at high
elevations above 5,000 ft. require the installation of a
high altitude kit that includes a new model data card for
proper operation.
NOTE:
High altitude operation is limited to a maximum
altitude of 8,000 ft.
All gas piping must comply with the latest NFPA 54
National Fuel Gas Code and all state and local codes.
All electrical wiring must comply with the latest NFPA
70, National Electrical Code and all state and local
codes.
Be sure to check the fuel code of your furnace. The
fuel code is adjacent to the serial number. See the LP
conversion kit index that came with your furnace to
determine the correct LP conversion kit.
4. All altitudes use a 1.10mm orifice. The unique 2% de-
rate requirement per 1000 ft. allows the lower baro-
metric pressure to meet this requirement.
LP CONVERSION
TABLE 12
LP GAS PIPE CAPACITY TABLE (CU. FT./HR.)
Maximum capacity of pipe in thousands of BTU per hour of undiluted liquefied petroleum gases (at 11 inches water
column inlet pressure).
(Based on a Pressure Drop of 0.5 Inch Water Column)
Nominal Length of Pipe, Feet
Iron Pipe
Size, Inches 10 20 30 40 50 60 70 80 90 100 125 150
1/2 275 189 152 129 114 103 96 89 83 78 69 63
3/4 567 393 315 267 237 217 196 182 173 162 146 132
1 1,071 732 590 504 448 409 378 346 322 307 275 252
1-1/4 2,205 1,496 1,212 1,039 913 834 771 724 677 630 567 511
1-1/2 3,307 2,299 1,858 1,559 1,417 1,275 1,181 1,086 1,023 976 866 787
2 6,221 4,331 3,465 2,992 2,646 2,394 2,205 2,047 1,921 1,811 1,606 1,496
Example (LP): Input BTU requirement of unit, 120,000
Equivalent length of pipe, 60 ft. = 3/4" IPS required.
!
WARNING
NEVER PURGE A GAS LINE INTO THE COMBUS-
TION CHAMBER. NEVER USE MATCHES, FLAME
OR ANY IGNITION SOURCE FOR CHECKING LEAK-
AGE. FAILURE TO ADHERE TO THIS WARNING CAN
CAUSE A FIRE OR EXPLOSION RESULTING IN
PROPERTY DAMAGE, PERSONAL INJURY OR
DEATH.
TO CHECK FOR GAS LEAKAGE, USE AN AP-
PROVED CHLORIDE-FREE SOAP AND WATER SO-
LUTION, OR OTHER APPROVED METHOD.
WARNING
!
