Weil-McLain WMBC-1A User Manual
LGB
Gas–fired boiler
Control Supplement
Flame Guardian WMBC-1A
RM7895C Controller Electronic Pilot System
IRI
Contents
I. Installation ..................... 2
II. Gas piping ...................... 5
III. Wiring ............................. 5
IV.Startup ......................... 10
V. Sequence of operation 11
VI.Parts list ....................... 12
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 damage.
This Control Supplement must only be used by a qualified installer/service
technician. Read these instructions completely before beginning the
installation. Failure to follow these instructions can cause severe personal
injury, death or substantial property damage.
Part Number 550-141-807/0298
LGB
(Series 2) — Control Supplement
I Installation
1. For use with LGB-6 through 12 boilers.
2. LOCAL INSPECTOR MUST CERTIFY BOILER FOR IRI COMPLIANCE.
3. Assemble pilot burner and flame sensor to main burners with pilot brackets. See Figures 2
and 3. Install ground wiring as shown in Figures 2 and 3.
4. Reinstall burner assemblies. See Table 1 for pilot burner and flame sensor locations.
5. Assemble control panel to boiler. See Figure 1.
6. Install gas controls as shown in Figure 4, page 4.
7. IRI installations require manual reset controls. Weil-McLain recommends installing manual
controls in addition to standard as required by local inspector. Refer to the LGB Boiler
Manual, “Boiler Controls” sect ion.
a. Steam boilers require a manual reset Low Water Cutoff and manual reset Pressure Limit
Control.
b. Water boilers require a manual reset Low Water Cutoff and manual reset Temperature
Limit Control.
Table 1
Pilot burner and flame sensor
locations
Figure 1
Mount control panel to jacket
as shown
Boiler Model Flame Sensor * Pilot Burner *
LGB-6 29
LGB-7 211
LGB-8 213
LGB-9 215
LGB-10 216
LGB-11 216
LGB-12 216
* From left burner.
Panel
Front of
Boiler
Drill (3) Holes in Front
Drill (7) 1/8“
Drill (7) 1/8“
Holes In Jacket
Holes In Jacket
to Mount
to Mount
Bracket
Bracket
Drill (4) Holes in SideDrill (4) Holes in Side
Part Number 550-141-807/02982
55BGL
Flame Guardian WMBC-1A Electronic Pilot System – IRI
I Installation – continued
Figure 2
Q179 pilot burner assembly
Figure 3
Main flame sensor assembly
LGB-A56
Locating Slot
Burner Support Bar
Pilot Line Tubing
Locating Slot
Sensor
Igniter
Sensor Lead
Flame
Sensor
Igniter Lead
Q179 Pilot
Burner
Compression
Union
10-32 x 5/16“
Machine Screws(2)
Ground Leadwire:
Connect to WMBC
Panel Terminal G2
(Ground Terminal)
Pilot Mounting
Bracket
10-32 x 1/4“
Machine Screws (2)
Main Burner
(with Pilot
Mounting
Bracket)
6-32 x 5/16“ Type ”F”
Self Tapping Screws(2)
10-32 x 5/16“
Machine Screws(2)
Ground Leadwire:
Connect to Main Flame
Proving Module
24 V (GND) terminal
Burner Support Bar
Flame Sensor
Mounting Bracket
Sensor Lead
LGB-A85
Main Burner
(with Pilot
Mounting
Bracket)
Part Number 550-141-807/0298 3
LGB
(Series 2) — Control Supplement
I Installation – continued
Figure 4
IRI gas train schematic
Atmosphere
Vent to Outside
6
5
3
7
Boiler Jacket
2
Drip Leg Service Valve
1718
1
4
8
GAS PIPING DIAGRAM - LGB (Series 2)
1
Manual main shut-off gas valve
2
Low gas pressure switch
3
Pilot manual shut-off valve
4
Motorized gas valve w/ on/off actuator
5
Pilot gas pressure regulator
6
Normally open solenoid vent valve
7
Pilot solenoid gas valve
8
Test cock
Second motorized gas valve w/ on/off actuator
9
18
11
9
IRI Gas Train
10
Manual leak checking gas valve
11
Regulating diaphragm gas valve (two stage)
12
High gas pressure switch
13
Main flame sensor
14
Main burner with main flame sensor bracket
15
Pilot burner
16
Main burner with pilot burner bracket
Adapter, for N. O. vent valve
17
18
Pipe flanges
10
12
14
1613 15
Part Number 550-141-807/02984
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