Return Air Connections
!WARNING
FIRE HAZARD
Failure to follow this warning could cause personal injury, death and/or property damage.
Never connect
Downflow Furnaces
The
Upflow and Horizontal Furnaces
The
Not all horizontal furnaces are approved for side return air connections. (See Fig. 20.)
GAS PIPING
!WARNING
FIRE OR EXPLOSION HAZARD
Failure to follow this warning could result in personal injury, death, and/or property damage.
Never purge a gas line into a combustion chamber. Never test for gas leaks with an open flame. Use a commercially available soap solution made specifically for the detection of leaks to check all connections.
!WARNING
FIRE OR EXPLOSION HAZARD
Failure to follow this warning could result in personal injury,death, and/or property damage.
Use proper length of pipe to avoid stress on gas control manifold and a gas leak.
!CAUTION
FURNACE OVERHEAT HAZARD
Failure to follow this caution may result in property damage.
Connect gas pipe to gas valve using a backup wrench to avoid damaging gas controls and burner misalignment.
!WARNING
FIRE OR EXPLOSION HAZARD
Failure to follow this warning could result in personal injury, death, and/or property damage.
If local codes allow the use of a flexible gas appliance connector, always use a new listed connector. Do not use a connector which has previously served another gas appliance. Black iron pipe shall be installed at the furnace gas control valve and extend a minimum of 2 in.(51 mm) outside the furnace.
Gas piping must be installed in accordance with national and local codes. Refer to current edition of NFGC in the U.S., the
Installations must be made in accordance with all authorities having jurisdiction. If possible, the gas supply line should be a separate line running directly from meter to furnace.
NOTE: In the state of Massachusetts:
1.Gas supply connections MUST be performed by a licensed plumber or gas fitter.
2.When flexible connectors are used, the maximum length shall not exceed 36 inches (915 mm).
3.When lever handle type manual equipment shutoff valves are used, they shall be
4.The use of copper tubing for gas piping is NOT approved by the state of Massachusetts.
Refer to Table 6 for recommended gas pipe sizing. Risers must be used to connect to furnace and to meter. Support all gas piping with appropriate straps, hangers, etc. Use a minimum of 1 hanger every 6 ft. (2 M). Joint compound (pipe dope) should be applied sparingly and only to male threads of joints. Pipe dope must be resistant to the action of propane gas.
An accessible manual equipment shutoff valve MUST be installed external to furnace casing and within 6 ft. (2 M) of furnace. A
NOTE: The furnace gas control valve inlet pressure tap connection is suitable to use as test gauge connection providing test pressure DOES NOT exceed maximum 0.5 psig
Some installations require gas entry on right side of furnace (as viewed in upflow.) (See Fig. 21.)
Install a sediment trap in riser leading to furnace as shown in Fig
22.Connect a capped nipple into lower end of tee. Capped nipple should extend below level of furnace gas controls. Place a ground joint union between furnace gas control valve and exterior manual equipment gas shutoff valve. A
58PHA
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