LGB-6 to LGB-23Series 2 – Control Supplement

IV Wiring – continued

Sequence of operation 1. Operating control begins start-up sequence.

a. Limit control contacts are closed.

2.Pilot-proving module energized.

On failure to sense pilot flame or main flame, control will wait 5 minutes then retry for ignition.

a.Pilot solenoid opens.

b.Pilot ignition spark begins.

c.Pilot ignites.

d.Pilot proves.

3.Main flame-proving module energized from pilot-proving module.

a.Secondary gas valve opens.

b.Main gas valve opens to low fire position.

c.Main burners ignite at low fire.

d.Main flame sensor proves low fire carryover.

e.Main gas valve opens to high fire position.

f.Main burners increase to high fire.

4.Dual base assembly (LGB-13 through LGB-23) - operating control energizes the controls for both base assemblies at the same time. See steps 1 through 3 above.

5.Boiler shuts down when the operating control is satisfied.

Wiring Procedure 1. Determine right or left electrical supply wiring.

2.Attach electrical junction box(es) to inside jacket end panel. Screws and nuts are provided. For dual base boilers, use offset nipples (provided) to connect juction boxes together, then hang junction boxes by screwing top box to boiler jacket. See Figure 4.

3.Attach control transformer(s) to junction box(es).

4.Drill 1/8” hole in interior jacket panel midway between ignition control panel and left jacket panel. Mount wire support clip using sheet metal screw (furnished).

5.Complete wiring per wiring diagram, Figure 3, pages 6 and 7. Terminate at secondary gas valve in valve junction box with wirenuts and strain relief provided.

“Hot” side of line voltage to boiler must be wired directly to limit circuit, then fed to transformer primary(ies). Dual Base: “R” terminal of secondaries are to supply power to bases independently of each other. Do not wire “R” terminals together.

6.Install pilot proving and main flame proving ground connections as shown in Figures 1, 2 and 3. Route wires through wire support clip.

7.Canada only - attach chain between junction box(es) and transformer with S-hooks.

Figure 4

Junction box assembly dual base boilers

8

Part Number 550-141-797/0798

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Weil-McLain LGB-17, LGB-7, LGB-14, LGB-8, LGB-20, LGB-13, LGB-15, LGB-12 manual IV Wiring, Junction box assembly dual base boilers
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LGB-19, LGB-6, LGB-8, LGB-11, LGB-7 specifications

Weil-McLain's LGB series of cast iron boilers, including models LGB-10, LGB-9, LGB-8, LGB-18, and LGB-15, are renowned for their efficiency, durability, and reliable performance in commercial and industrial heating applications. These boilers are designed to meet a broad range of heating demands, making them a popular choice among professionals in the HVAC industry.

One of the main features of the LGB series is its sectional cast iron design. This allows for superior heat retention and efficient heat transfer, ensuring minimal energy loss throughout the heating process. The cast iron construction also provides exceptional durability, allowing these boilers to withstand high operating pressures and prolonging their lifespan compared to other materials.

The LGB series employs an advanced burner system that enhances combustion efficiency. The gas-fired models are equipped with a power burner that ensures precise fuel-to-air ratios, resulting in optimal combustion and reduced greenhouse gas emissions. Additionally, Weil-McLain boilers are designed to operate quietly, making them suitable for use in noise-sensitive environments.

A significant technological advancement in these models includes their electronic ignition systems, which eliminate the need for pilot lights, thereby increasing safety and reducing energy consumption. This technology also contributes to the overall ease of operation. The series features a wide range of firing rates, enabling users to adjust the boiler’s output according to specific heating requirements.

The LGB-10, LGB-9, LGB-8, LGB-18, and LGB-15 models are available with various options such as built-in draft diverters and low water cut-off features to enhance safety and performance. Moreover, these boilers are compatible with different types of heating systems, including hot water and steam applications, making them versatile for a variety of installations.

In terms of efficiency, the Weil-McLain LGB series typically achieves an Annual Fuel Utilization Efficiency (AFUE) rating that meets or exceeds industry standards, ensuring lower operational costs and energy savings for consumers. This combination of features, technologies, and characteristics makes the Weil-McLain LGB series an exceptional choice for those looking for reliable and efficient heating solutions in demanding applications.
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