Weil-McLain LGB-23 Manuale Utente
4
LGB-6 to LGB-23
Series 2 – Control Supplement
Part Number 550-141-916/1001
1. Size gas piping considering —
a. Diameter and length of gas supply piping.
b. Number of fittings.
c. Maximum gas consumption (including any possible future expansion).
d. Allowable pressure drop from gas meter outlet to boiler. For pressure drops, see
b. Number of fittings.
c. Maximum gas consumption (including any possible future expansion).
d. Allowable pressure drop from gas meter outlet to boiler. For pressure drops, see
ANSI-Z223.1 – latest edition. Canadian installations must comply with B149.1 or
B149.2 Installation Code.
B149.2 Installation Code.
2. Size natural gas piping from Table 3, below. Size piping to provide proper inlet pressure to
gas valve when operating at rated input.
a. Inlet gas pressure to manual main shut-off gas valve —
a. Inlet gas pressure to manual main shut-off gas valve —
minimum 7" W.C. standard (5" on special order) – maximum 13" W.C.
b. If pressure to gas valve exceeds 13" W.C., install positive dead-end lockup gas pressure
regulator upstream of hand valve.
c. To obtain approximate cubic feet per hour, divide input (BTU/HR) by 1000.
3. Remove gas supply knockout disc from jacket panel.
4. Follow good piping practices.
5. Pipe joint compound (pipe dope) must be resistant to corrosive action of liquefied
4. Follow good piping practices.
5. Pipe joint compound (pipe dope) must be resistant to corrosive action of liquefied
petroleum gases. Apply sparingly only to male threads of pipe joints.
6. Install drip leg at inlet of gas connection to boiler. Where local utility requires, extend drip
leg to floor.
7. Install ground joint union when required for servicing.
8. Support piping by hangers, not by boiler or its accessories.
9. Purge all air from supply piping.
10. Before operating boiler, check boiler and its gas connections for leaks.
8. Support piping by hangers, not by boiler or its accessories.
9. Purge all air from supply piping.
10. Before operating boiler, check boiler and its gas connections for leaks.
Table 3
Natural gas supply pipe sizing
10
20
30
40
50
75
100
150
1 ¼"
1,050
730
590
500
440
360
305
250
1 ½"
1,600
1,100
890
760
670
545
460
380
2"
3,050
2,100
1,650
1,450
1,270
1,020
870
710
2 ½"
4,800
3,300
2,700
2,300
2,000
1,650
1,400
1,130
3"
8,500
5,900
4,700
4,100
3,600
2,900
2,500
2,000
4"
17,500
12,000
9,700
8,300
7,400
6,000
5,100
4,100
*Pipe length, in feet (Natural Gas capacities, listed in MBH)
Pipe
Size
Size
*Include measured length of gas supply piping and allowance in feet for number and size of fittings.
II
Gas piping
Do not check for gas leaks with an open flame – BUBBLE TEST. Failure to
use bubble test or test for leaks can cause severe personal injury, death or
substantial property damage.
use bubble test or test for leaks can cause severe personal injury, death or
substantial property damage.
a. Close manual main shut-off valve during any pressure testing at less than 13" W.C.
b. Disconnect boiler and gas controls from gas supply piping during any pressure test
b. Disconnect boiler and gas controls from gas supply piping during any pressure test
greater than 13" W.C.
11. Set gas pressure switch as follows or to local inspector’s requirements (LGB-21 through
LGB-23 only):
a. High – 14" W.C.
a. High – 14" W.C.
12. Canada only - manual main shut-off valve must be identified by installer.