Modine Manufacturing HD Installation And Service Manual - page 7
7
Piping
1.
Installation of piping must be in accordance with local codes,
and ANSI Z223.1, “National Fuel Gas Code,” or CAN/CGA-
B149 in Canada.
2.
Piping to units must conform with local and national
requirements for type and volume and gas handled, and
pressure drop allowed in the line. Refer to Table 5, to
determine the cubic feet per hour (cfh) for the type of gas and
size of unit to be installed. Using this cfh value and the length
of pipe necessary, determine the pipe diameter from Table 3.
Where several units are served by the same main, the total
capacity, cfh, and length of main must be considered. Avoid
pipe sizes smaller than 1/2". Table 2 allows for the usual
number of fittings with a 0.3" W.C. pressure drop. Where the
gas supplied has a specific gravity other than 0.60, apply the
multiplying factor as given in Table 3.
3.
After threading and reaming the ends, inspect piping and
remove loose dirt and chips.
4.
Support piping so that no strains are imposed on unit or
controls.
5.
Use two wrenches when connecting piping to unit controls.
6.
Provide a drip sediment trap before each unit and in the line
where low spots cannot be avoided. (See Figure 9).
7.
Take-off to unit should come from top or side of main to avoid
trapping condensate.
8.
Piping, subject to wide temperature variations, should be
insulated.
9.
Pitch piping up toward unit at least 1/4" per 15' of horizontal
run.
10. Compounds used on threaded joints of gas piping must be
resistant to action of liquefied petroleum gases.
11. Purge air before lighting unit by opening inlet pressure at top in
combination gas control.
12. After installation, check system for gas leaks, using a soap
solution.
13. Install a ground joint union and a manual shut off valve within
6' of the unit including a 1/8" NPT plugged tapping accessible
for test gage connection. (See Figure 9).
14. Allow at least 5 feet of piping between any high pressure
regulator and unit control string.
15. When leak testing the gas supply piping system, the appliance
and its combination gas control must be isolated during any
pressure testing in excess of 14" W.C. (1/2 psi)
The appliance should be isolated from the gas supply piping
system by closing its field installed manual shutoff valve.
INSTALLATION
Figure 7
Horizontal Venting with Downward Pitch
(with drip leg)
Figure 8
Horizontal Venting with Downward Pitch
(Condensate Drips Out End)
4" Min to combustibles
1
/
4
" Slope down towards termination
Listed Thimble
11"
3' Min
4" Min to combustibles
1
/
4
" Slope down towards termination
Listed Thimble
11"
3' Min
CAUTION
Check the gas inlet pressure at the unit upstream of the
combination gas control. The inlet pressure must be 6-7"
W.C. on natural gas or 12-14" W.C. on propane.
Purging of air from gas lines and piping should be performed
as described in ANSI Z223.1-latest edition CAN/CGA-B149
codes.
Gas pressure to unit heater controls must never exceed 14"
W.C. (1/2 psi).
When leak testing the gas supply piping system, the
appliance and its combination gas control must be isolated
during any pressure testing in excess of 14" W.C. (1/2 psi).
The unit should be isolated from the gas supply piping
system by closing its field installed manual shut-off valve.
This manual shut-off valve should be located within 6' of
the heater.
!
Modine Specified Cap (See No.4, page 6)
Modine Specified Cap (See No.4, page 6)