bolts have been installed, draw each one gradually
until all are uniformly and properly tight. Avoid
drawing bolts too tight, as this can crack or break a
casting or buckle a steel plate.
After assembling the furnace, check all doors for
free operation and tight fit.
Install the downdraft diverters furnished with the
equipment on all gas-burning furnaces. Diverters are
developed for individual furnaces.
Use a vent or smoke pipe that is at least as large as
the smoke-pipe outlet of the furnace.
Securely fasten the vent or smoke pipe at each joint
with a minimum of three sheet metal screws. Install
horizontal pipe with a pitch upward of at least l-inch
per linear foot (fig. 4-51).
Ventilate the furnace room adequately to supply
air for combustion. Provide an opening having 1
square inch of free-air area for each 1,000 Btu per hour
of furnace input rating with a minimum of 200 square
inches. Locate the opening at or near the floor line
whenever possible. In addition, provide two louvered
openings, each having a free-air area of at least 200
square inches in it, at or near the ceiling as near
opposite ends of the furnace room as possible.
Tank installation is largely governed by local
conditions. Listed here are the principles of tank
installation that give greatest freedom from service
problems. Adhere as closely to these recom-
mendations as local conditions permit.
Figure 4-51.Typical smoke pipe (flue) installation.
When possible, install single-pipe gravity oil feed
on inside tanks or elevated outside tanks (fig. 4-52).
This type of installation is used for single-stage pumps.
Use a 1/4-inch globe valve at the tank instead of a
larger size. Larger valves sometimes cause tank hum.
For all installations, use a continuous piece of
1/2-inch copper tubing from the oil tank or valve to the
burner and a similar piece for the return when required.
The principle is to minimize the number of joints and
thus minimize the possibility of air or oil leaks.
For inside installations where it is necessary to run
the piping overhead between the tank and burner, when
the burner is either above or below the tank level, the
two-pipe system is recommended. This requires the
use of a two-stage pump.
A dual-stage pump may be changed from a
single-stage to a two-stage pump to accommodate a
single-pipe or two-pipe system. The stages on a
Webster fuel pump can be changed by removing the
four screws on the pressure side of the pump and lining
the Number 1 up with the letter on the pump body for a
one-pipe system. The Number 2 lined up with the letter
is for a two-pipe system. Most Sunstrand fuel pumps
are shipped from the factory set up for a one-pipe
system. To change to a two-pipe system, remove the
3/8-inch pipe plug from the bottom of the pump
housing. There you will find an Allen head plug.
Remove this plug for a two-pipe system.
Install the outside tanks (fig. 4-53) according to the
Normally, when you are installing an underground
fuel tank, the suction and return lines are made of black
iron from the tank to the inside of the building, and
there the burner is connected by copper tubing with a
coil in it (not shown in the illustration) to eliminate
The return line is usually installed in the opposite
end of the tank. Carry it to within 5 inches of the
bottom. This creates an oil seal in the two lines, and any
agitation caused by return oil is safely away from the
A 1 1/2-inch fill line and a 1 1/2-inch vent line are
recommended. Carry the vent well aboveground and
put a weatherproof cap on it. Pitch the vent line down
toward the tank.
Use special pipe dope on all iron pipe fittings that
carry oil. Treat the underground outside tank and
piping with a standard preparation or commercial