Weil-McLain LGB-4, LGB-5 User Manual

LGLG

LG

LGLG

Control SupplementControl Supplement

Control Supplement

Control SupplementControl Supplement

BB

B

BB

Gas–fired boiler

LGBLGB

LGB

LGBLGB

Universal Control System

-4 -4

-4 &

-4 -4

LGB LGB

LGB

LGB LGB

-5-5

-5 Series 2 – Natural gas

-5-5

Contents

Installation ....................... 2

Gas piping .........................3

Wiring ............................... 4

Operating instructions ..... 6

Verification testing .......... 7

Parts ................................. 8

These terms are used throughout this

manual to bring attention to the presence

of hazards of various risk levels or to

important information concerning the life

of the product.

Refer to

LGBLGB

LGB • Installation •

LGBLGB

Start-Up • Service •

Parts Manual

for additional information

Indicates presence of hazards that can cause severe personal injury, death or
substantial property damage.

Indicates special instructions on installation, operation or maintenance that
are important but not related to personal injury or property.

Control Supplement must only be used by a qualified installer/service
technician. Read all instructions before installing. Failure to follow all
instructions in proper order can cause severe personal injury, death or
substantial property damage.

Part Number 550-141-918/0304

LGBLGB

LGB

LGBLGB

-4 -4

-4 &

-4 -4

I Installation

Install pilot burner. See Figures 1a and 1b. Follow Figure 1b for pilot burner location, placing
the burner with pilot bracket in the fourth position from the left for the LGB-4 and the fifth
position from the left for the LGB-5, as shown.

Install gas controls and ignition control as shown in Figure 3 on page 7.

In Canada — mount rating plate on interior jacket panel.

Figure 1a

Pilot burner

assembly

5 5

5

5 5

•

Control Supplement • UCS • Nat. Gas

Figure 1b

Pilot location

2

Part Number 550-141-918/0304

LGBLGB

LGB

LGBLGB

-4 -4

-4 &

-4 -4

5 5

5

5 5

II Gas piping

•

Control Supplement • UCS • Nat. Gas

Supply pipe sizing

Connect gas piping

to boiler

1. Size natural gas piping from Table 1. 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 minimum 5" W.C., maximum

13" W.C.

b. If pressure to gas valve exceeds 13" W.C., install 100% lock-up gas pressure regulator

upstream of hand valve.

c. To obtain approximate cubic feet per hour, divide input (Btu/hr) by 1000.

2. 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 to boiler. For pressure drops, see ANSI

Z233.1 latest edition. Canadian installations must comply with B149.1 or B149.2
Installation Code.

3. Remove knockout disc from jacket panel side to which gas supply will be piped.

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 code/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.

Do not check for gas leaks with an open flame - use bubble test. Failure to
use bubble test or check for leaks can cause severe personal injury, death or
substantial property damage.

a. Close manual main shut-off valve during any pressure testing greater than 13" W.C.
b. Disconnect boiler and gas valve from gas supply piping during any pressure test

greater than 13" W.C.

11. In Canada — manual main shut-off valve must be identified by installer.

Table 1

Gas supply pipe

capacities

Part Number 550-141-918/0304

Pipe length, feet *

PIPE
SIZE

10 20 30 40 50 75 100 150

1 1/4" 1,050 730 590 500 440 360 305 250

1 1/2" 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 1/2" 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

*Include measured length of gas supply piping and allowance in feet for number and size of fittings.

(Natural gas capacities given in MBH)

(Specific Gravity 0.60 @ Pressure Loss of 0.30" W.C.)

3