GAS FIRED VENTED FLOOR FURNACES
11
GAS SUPPLY AND PIPING
The gas piping system must meet the requirements of local
codes or the specifications of the servicing gas supplier. It
must have adequate capacity to supply the floor furnace
and any other appliance within the home with enough
gas to maintain the full rated capacities without excessive
pressure drop when all appliances are operating at full rate.
GAS PIPE SIZES - CAPACITY NATURAL GAS
*
LENGTH OF
PIPE - FEET
INSIDE PIPE DIAMETER
1/2"
3/4"
1"
10
132,000
278,000
520,000
CAPACITY
BTU/hr
INPUT
20
92,000
190,000
350,000
30
73,000
152,000
285,000
40
63,000
130,000
245,000
50
56,000
115,000
215,000
60
50,000
105,000
195,000
* Based on heating value of 1,000 value of 1,000 BTU per cubic
foot(specif ic gravity of 0.6) at 0.5 PSIG and a pressure drop of
0.3 inch water column.
GAS TUBING AND PIPE SIZES - CAPACITY PROPANE GAS
*
LENGTH
OF PIPE
FEET
COPPER TUBING
OUTSIDE DIAMETER
**
STEEL PIPE
INSIDE DIAMETER
***
1/2"
3/4"
1/2"
3/4"
CAPACITY
BTU/hr
INPUT
10
92,000
329,000
275,000
567,000
20
62,000
216,000
189,000
393,000
30
50,000
181,000
152,000
315,000
40
41,000
145,000
129,000
267,000
50
37,000
131,000
114,000
237,000
60
35,000
121,000
103,000
217,000
* Undiluted Liquefied Petroleum Gas at 11 inches water column inlet
pressure. Based on a pressure drop of 0.5 inches water column.
** Copper tubing must comply with limitations of NATIONAL FUEL GAS
CODE reference 2.6.3 metallic tubing.
*** Steel pipe should be of at least standard weight (Schedule 40).
Support the piping or tubing at regular intervals with
metal pipe strapping. See charts below.
NOMINAL STEEL PIPE SIZE
SPACING OF SUPPORTS
1/2
"
6’
3/4
"
or 1
"
8’
NOMINAL SIZE OF TUBING O.D.
SPACING OF SUPPORTS
1/2
"
4’
5/8
"
or 3/4
"
6’
• Where local conditions include earthquake, tornado,
unstable ground or flood hazards, give special
consideration to increased strength and flexibility
of piping supports and connections. Consult local
authorities for recommendations.
• All unused openings in the piping system must be
securely closed gas-tight.
Refer to
Figure 10
for the basic fittings you will need
at the furnace.
1. Use black iron or steel pipe and fittings or other pipe
and fittings that are approved by local codes.
2. Use pipe joint compound that is resistant to the action
of Propane Gas or to any other chemical constituents of
the gases to be conducted through the piping only on
male threads.
3. Use two wrenches when making the connection to the
valve to keep from bending the mounting bracket or
manifold pipe. Do not over tighten as damage to the
valve can occur.
4. Provide a 1/8” nominal pipe thread (NPT) plugged
tapping for test gauge connection immediately
upstream of the gas supply connection to the floor
furnace.
5. Provide a sediment trap at least 6 inches long to trap
dirt and moisture. Provide space to permit cleaning
or emptying.
6. Use a ground joint union.
7. Install an approved manual shut-off valve.
TO HEATER GAS
CONTROL VALVE
MANUAL CUT-OFF VALVE
DRIP LEG
1/8" NPT
PRESSURE TAP
GAS
SUPPLY
LINE
