Allied Air Enterprises 92G1UH, A95UH, 95G1UH Gas Piping, Leak Check, Fire or Explosion Hazard

Gas Piping

CAUTION

If a flexible gas connector is required or allowed by the authority that has jurisdiction, black iron pipe shall be installed at the gas valve and extend outside the furnace cabinet. The flexible connector can then be added between the black iron pipe and the gas supply line.

WARNING

Do not exceed 600 in.-lbs. (50 ft.-lbs.) torque when attaching the gas piping to the gas valve.

1.Gas piping may be routed into the unit through either the left or right hand side. Supply piping enters into the gas valve from the side of the valve as shown in Figure 47. Move Bellows grommet to side which gas line enters. Ensure opposite gas line hole is plugged with supplied plug.

IMPORTANT

The gas valve requires a low inlet pressure switch in LP/propane applications. A 4” BIP nipple must be installed in the gas valve inlet when right-side gas entry is used in LP/propane applications. See Figure 47.

2.When connecting gas supply, factors such as length of run, number of fittings and furnace rating must be considered to avoid excessive pressure drop. Table 7 list recommended pipe sizes for typical applications.

NOTE: Use two wrenches when connecting gas piping to avoid transferring to the manifold.

3.Gas piping must not run in or through air ducts, clothes chutes, chimneys or gas vents, dumb waiters or elevator shafts. Center gas line through piping hole. Gas line should not touch side of unit. See Figures 47 and 48.

4.Piping should be sloped 1/4 “ per 15 feet (6 mm per 5.6 m) upward toward the gas meter from the furnace. The piping must be supported at proper intervals, every 8 to 10 feet (2.44 to 3.05 m), using suitable hangers or straps. Install a drip leg in vertical pipe runs to serve as a trap for sediment or condensate.

5.A 1/8” N.P.T. plugged tap or pressure post is located on the gas valve to facilitate test gauge connection. See Figure 55.

6.In some localities, codes may require installation of a manual main shut-off valve and union (furnished by installer) external to the unit. Union must be of the ground joint type.

IMPORTANT

Compounds used on threaded joints of gas piping must be resistant to the actions of liquified petroleum gases.

Leak Check

After gas piping is completed, carefully check all piping connections (factory and field installed) for gas leaks. Use a leak detecting solution or other preferred means.

Never use an open flame to test fro gas leaks. Check all connections using a commercially available soap solution made specifically for leak detection.

The furnace must be isolated from the gas supply system by closing its individual manual shut-off valve during any pressure testing of the gas supply system at pressures more than or equal to 1/2 psig (3.48 kPa, 14 inches w.c.).

Figure 46

IMPORTANT

When testing pressure of gas lines, gas valve must be disconnected and isolated. See Figure 46. Gas valves can be damaged if subjected to pressures greater than 1/2 psig (3.48 kPa).

WARNING

FIRE OR EXPLOSION HAZARD

Failure to follow the safety warnings exactly could result in serious injury, death, or property damage. Never use an open flame to test for gas leaks. Check all connections using a commercially available soap solution made specifically for leak detection. Some soaps used for leak detection are corrosive to certain metals. Carefully rinse piping thoroughly after leak test has been completed.

506501-01 Issue 1031 Page 31 of 48