20
Return Air Connections
FIRE HAZARD
A failure to follow this warning could cause personal injury,
death and/or property damage.
Never connect return--air ducts to the back of the furnace.
Follow instructions below.
!
WARNING
Downflow Furnaces
The return--air duct must be connected to return--air opening
(bottom inlet). DO NOT cut into casing sides (left or right). Side
opening is permitted for only upflow and certain horizontal
furnaces. Bypass humidifier connections should be made at
ductwork or coil casing sides exterior to furnace. (See Fig. 19.)
Upflow and Horizontal Furnaces
The return--air duct must be connected to bottom, sides (left or
right), or a combination of bottom and side(s) of main furnace
casing. Bypass humidifier may be attached into unused return air
side of the furnace casing. (See Fig. 18 and 20.) Not all horizontal
furnace models are approved for side return air connections. (See
Fig. 20.)
GAS PIPING
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. A fire or explosion may
result causing property damage, personal injury or loss of
life.
!
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.
!
WARNING
FIRE OR EXPLOSION HAZARD
Failure to follow this warning could result in personal
injury, death, and/or property damage.
Gas valve inlet and/or inlet pipe must remain capped until
gas supply line is permanently installed to protect the valve
from moisture and debris. Also, install a sediment trap in the
gas supply piping at the inlet to the gas valve.
!
WARNING
Gas piping must be installed in accordance with national and
local codes. Refer to current edition of NFGC in the U.S.
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 li-
censed plumber or gas fitter.
2. When flexible connectors are used, the maximum length
shall not exceed 36 in. (915 mm).
3. When lever handle type manual equipment shutoff valves
are used, they shall be T--handle valves.
4. The use of copper tubing for gas piping is NOT approved
by the state of Massachusetts.
Refer to Table 5 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. (1.8 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.
Table 5 – Maximum Capacity of Pipe
NOMINAL
IRON PIPE
SIZE
IN. (MM)
INTERNAL
DIA.
IN. (MM)
LENGTH OF PIPE --- FT (M)
10
(3.0)
20
(6.0)
30
(9.1)
40
(12.1)
50
(15.2)
1/2 (12.7)
0.622(158)
175
120
97
82
73
3/4 (19.0)
0.824 (20.9)
360
250
200
170
151
1 ( 25.4)
1.049 (26.6)
680
465
375
320
285
1-1/4
(31.8)
1.380 (35.0)
1400
950
770
660
580
1-1/2
(38.1)
1.610 (40.9)
2100
1460
1180
990
900
* Cubic ft of gas per hr for gas pressures of 0.5 psig (14--- In. W.C.) or less and
a pressure drop of 0.5--- In. W.C. (based on a 0.60 specific gravity gas). Ref:
Table 6 and 9.2 NFGC.
FIRE OR EXPLOSION HAZARD
A 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.
!
WARNING
FURNACE DAMAGE HAZARD
Failure to follow this caution may result in furnace damage.
Connect gas pipe to furnace using a backup wrench to
avoid damaging gas controls and burner misalignment.
CAUTION
!
An accessible manual equipment shutoff valve MUST be
installed external to furnace casing and within 6 ft. (1.8 M) of
furnace. A 1/8--in. (3 mm) NPT plugged tapping, accessible for
test gauge connection, MUST be installed immediately upstream
of gas supply connection to furnace and downstream of manual
equipment shutoff valve.
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 (14--In.
W.C.) stated on gas control valve. (See Fig. 49.)
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
314AA
V
Содержание 314A
Страница 3: ...3 A10269 Fig 1 Clearances to Combustibles 314AAV...
Страница 41: ...41 A13214 Fig 55 Wiring Diagram 314AAV...