Table of Contents
Advertisement
CAUTION
A separate drain line must be run to the drain from the
condensate trap. DO NOT connect the condensate
trap drain into the drain line from the evaporator coil.
UNIT WITH EVAPORATOR COIL
Figure 27
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.
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
29.
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 9
lists recommended pipe sizes for typical applications.
NOTE: Use two wrenches when connecting gas piping to
avoid transferring torque 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 Figure 29.
Page 20 of 52
4. Piping should be sloped 1/4 inch per 15 feet (6mm per
5.6m) upward toward the gas meter from the furnace.
The piping must be supported at proper intervals, every
8 to 10 feet (2.44 to 3.05m), 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
Figures 35.
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.
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.
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 less
than or equal to 1/2 psig (3.48 kPa, 14 inches w.c.).
When testing gas lines using pressures in excess of 1/2
psig (3.48 kPa), gas valve must be disconnected and
isolated. See Figure 28. Gas valves can be damaged if
subjected to pressures greater than 1/2 psig (3.48 kPa).
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.
Issue 1034
IMPORTANT
Figure 28
CAUTION
WARNING
506552-01
Advertisement
Table of Contents
