Part number 550-101-232/0703
15
GAS-FIRED WATER BOILER — Installation Manual — Multiple-boiler Systems
Figure 14 Common gas piping, with manifolded gas header
Common gas piping installation
4. Size gas piping from meter outlet to entrance of gas header in
accordance with Tables 1 and 2 below. For gases with other
specific gravity or for different pressure drop or other pipe
sizes, refer to the National Fuel Gas Code or applicable local
codes.
Pipe lengths in Table 1 are equivalent length of straight pipe.
Convert pipe fittings to equivalent lengths using data from
Table 2.
5. Refer to page 14 of this manual and to the Ultra Boiler Manual
for testing gas piping.
1. Construct gas header for multiple boilers using Figure 14 and
the sizing tables below. Refer to the National Fuel Gas Code for
other conditions.
2. Provide manual shutoff gas valve and ground joint union as
shown in Figures 13 and 14 for each boiler. When gas line en-
ters from top of the boilerl, the boiler internal gas piping pro-
vides a drip leg. See boiler manual for details.
3. A ¾" NPT gas piping riser from header to boiler will be
large enough for most jobs. Check pressure drop.
Table 1 Capacity of gas piping for gas at 0.60 specific
gravity at a pressure drop of 0.30 inches w.c.
Table 2 Equivalent lengths of straight pipe
for typical gas line fittings
