Sentinel
13
GAS PIPING
A. Local installation codes apply. The pipe joint compound
used on threads must be resistant to the action of liquefied
petroleum gases.
B. The gas supply line to the boiler should be run directly from
the meter for natural gas or from the fuel tank for L.P.
propane gas. See page 2 for location of union and manual
main shutoff valve that may be specified locally.
Selecting pipe size for natural gas:
1. Measure or estimate the length of piping from the meter
to the installation site.
2. Consult gas supplier for heating value of gas-W/m
3
(BTU/cu. ft.).
3. Divide boiler rated input by heating value to find gas
flow in piping (m
3
/hr) (cu. ft. per hour).
4. Use table below to select proper pipe size.
Example: Boiler model SE-175 is to be installed. Distance
from gas meter to the boiler is 6.1m (20 ft). Heating value of
natural gas is 10560 W/m
3
(1020 BTU/cu. ft.) Select proper
pipe size.
At 6.1m
(20 ft.) length of pipe, match required capacity from table
below (choose higher capacity, in this case is 5.4 m
3
[190
cu. ft.] per hour). Required pipe size is 3/4".
Improper gas pipe sizing will result in pilot flame outages,
insufficient heat and other installation difficulties. For more
information and also if other appliances are to be attached
to the piping system, see Appendix C of National Fuel Gas
Code ANSI Z2231 latest edition or CSA B 149.1 latest edi-
tion for natural gas and propane.
C. The boiler and its gas connection must be leak tested
before placing the boiler in operation. Use liquid soap solu-
tion for all gas leak testing. Do not use open flame.
This boiler and its individual shutoff valve must be discon-
nected from the gas supply piping system during any pres-
sure testing of that system at test pressures in excess of
3.5 kPa (1/2 PSIG). This boiler must be isolated from the
gas supply piping system by closing its individual manual
shutoff valve during any pressure testing of the gas supply
piping system at test pressures equal to or less than 3.5
kPa (1/2 PSIG).
D. All gas piping used should be inspected thoroughly for
cleanliness before makeup. A sediment trap must be pro-
vided, as illustrated on page 2.
E. The minimum and maximum gas supply pressure (at the
inlet of gas valve) are shown on the boiler rating plate for
the type of gas used. Gas supply pressure should never be
less than minimum or more than maximum pressure when
the boiler or any other appliance is turned on or off.
BOILER ROOM AIR SUPPLY AND VENTILATION
An ample supply of air is required to obtain combustion and
ventilation. ALL AIR COMES FROM OUTSIDE, directly through
wall openings to the boiler or through unsealed openings
around windows, doors, etc. in the whole building. When
buildings are insulated, caulked and weather stripped, now or
later on, direct openings to outside may be required and
should be provided. If the boiler is not near an outside wall, air
may be ducted to it from outside wall openings.
Provisions for combustion and ventilation air must be made in
accordance with section 5.3, Air for Combustion and Ventila-
tion, of the National Fuel Gas Code, ANSI Z2231 latest edition
or CSA B 149.1 latest edition for natural gas and propane, or
applicable provisions of the local building codes. The follow-
ing recommendation applies to buildings of energy-saving
construction, fully caulked and weather stripped:
INSTALLATION IN ENCLOSED BOILER ROOM REQUIRES
TWO UNOBSTRUCTED OPENINGS FOR PASSAGE OF AIR
INTO THE BOILER ROOM:
1. Air drawn horizontally from outdoors DIRECTLY through an out-
side wall; one louvered opening near the floor and one louvered
opening near the ceiling, each opening with a minimum FREE air
passage area of 550 mm2 per kW (1 square inch per 4000 BTUH)
of total appliances’ input.
2. Air drawn horizontally through HORIZONTAL DUCTS; one open-
ing near the floor and one opening near the ceiling, each opening
with a minimum FREE air passage area of 1100 mm2 per kW (1
square inch per 2000 BTUH) of total appliances’ input.
3. Air drawn VERTICALLY from outdoors; one opening at the floor
and one opening at the ceiling, each opening with a minimum
FREE air passage area of 550 mm2 per kW (1 square inch per
4000 BTUH) of total appliances’ input.
4. Air drawn from inside the building; one opening near the floor and
one opening near the ceiling, each opening with a minimum
FREE air passage area of 2200 mm2 per kW (1 square inch per
1000 BTUH) of total appliances’ input.
IF BOILERS ARE INSTALLED ADJACENT TO OTHER FUEL
BURNING EQUIPMENT, THE AREA OF FREE OPENINGS
MUST BE APPROPRIATELY INCREASED TO ACCOMMODATE
THE ADDITIONAL LOAD.
Openings must never be reduced or closed. If doors or win-
dows are used for air supply, they must be locked open. Protect
against closure of openings by snow and debris. Inspect fre-
quently.
No mechanical draft exhaust or supply fans are to be used in or
near the boiler area.
The flow of combustion and ventilating air to the boiler must not
be obstructed.
Gas flow =
= 4.9 m
3
/hr
51 290 W/hr
10 560 W/m
3
(
Gas flow =
= 171.5 cu. ft. per hour
)
175,000 BTU/hour
1020 BTU/cu. ft.
1/2”
3/4”
1”
1 1/4”
1 1/2”
m
ft
m
3
/hr cu.ft./hr. m
3
/hr cu.ft./hr. m
3
/hr cu.ft./hr. m
3
/hr cu.ft./hr. m
3
/hr cu.ft./hr.
3.0
10
3.7
132
7.9
278
14.7 520
29.7 1050
45.3 1600
6.1
20
2.6
92
5.4
190
9.9
350
20.7 730
31.1 1100
9.1
30
2.1
73
4.3
152
8.1
285
16.7 590
25.2 890
12.2
40
1.8
63
3.7
130
6.9
245
14.2 500
21.5 760
15.2
50
1.6
56
3.3
115
6.1
215
12.5 440
19.0 670
18.3
60
1.4
50
3.0
105
5.5
195
11.3 400
17.3 610
21.3
70
1.3
46
2.7
96
5.1
180
10.5 370
15.9 560
24.3
80
1.2
43
2.5
90
4.8
170
9.9
350
15.0 530
27.4
90
1.1
40
2.4
84
4.5
160
9.1
320
13.9 490
30.5
100
1.1
38
2.2
79
4.2
150
8.6
305
13.0 460
Length
of Pipe
Gas Flow In Piping
Pressure drop=8mm(0.3") water column, 0.60 specific gravity gas.
Iron Pipe Size (Ips) inches
At pressure drop of 0.3 in. water, specific gravity = 0.60 gas.
