Overview of Primary Product

Part Number 550-141-186/0914
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LGB 3ERIES'AS&IRED"OILER"OILER-ANUAL
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 )NSTALLSYSTEMSUPPLYANDRETURNPIPINGBEFOREERECTINGJACKETORINSTALL-
ing controls.
2. Do not pipe in through supply and out through return. This creates
reverse water flow that must not be used.
 %XPANSIONTANK
A #LOSEDTYPEEXPANSIONTANKCONNECTTOvTAPPINGh
F” (refer to Ta p -
ping tables
PAGESAND5SEv.04PIPING!NYHORIZONTAL
PIPINGMUSTPITCHUPWARDTOWARDTANKATLEASTINCHFOREACHFEET
of piping. See
Figure 14.
b. Diaphragm type expansion tank — locate between supply and inlet
to circulator. Install automatic air vent in tapping “F”.
4. Connect supply and return piping:
a. Size according to tables on this page.
b. Install circulator in supply piping, with the expansion tank
located on the suction side of the circulator.
C )NSTALLSYSTEMDRAINVALVESIZEDPER!3-%#ODE
Models LGB-4 – LGB-12 — use 1” drain valve.
Models LGB-13 – LGB-23 — use 1¼” drain valve.
5. When three-way valves are used for temperature modulation, install
slow-opening valves and boiler mixing pump to minimize potential of
boiler thermal shock. See
Weil-McLain Bulletin AE-8402.
 -ULTIPLEBOILERSSEEFigure 15PAGE
 0IPINGSHOULDBESIZEDFORA&RISETHROUGHTHEBOILER3EETable 1,
below. For higher flow rates (when specified), use pipe sizes no smaller
than those given in Table 2, below.
8*
20°F rise
through
boiler
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3a
Piping — water boilers
Improper piping systems and/or undersized piping can contribute to erratic
boiler operation and possible boiler damage. Install piping as shown below.
LGB-4 through LGB-12 only — supply and return piping can be on same
end.
Intermittent flow at higher velocities than shown for pipe size in Table 2,
below, can damage boiler causing substantial property damage.
1 -ODELS,'"THROUGH,'"ONLYALTERNATESUPPLYTAPPINGFORSUPPLYANDRETURN
on same end.
2 -ODELS,'"THROUGH,'"ONLYALTERNATERETURNTAPPINGFORSUPPLYANDRETURN
on same end.
3 Location for closed type expansion tanks only. Locate diaphragm type expansion tanks
between boiler supply connection and circulator suction connection.
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8+
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
Boiler
Model
Number
Pipe Size
Supply &
Return
LGB-4
2”
LGB-5
2½”
LGB-6 – LGB-8
3”
LGB-9 – LGB-16
4”
LGB-17 – LGB-23
5”
Water Flow Rate
GPM
Pipe Size
Supply &
Return
Up to 35
2”
36 to 50
2½”
51 to 77
3”
78 to 142
4”
143 to 237
5”
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Water boiler
piping