LGB
LGB
LGB
LGB
LGB
Gas-Fired Boiler — Boiler Manual
Part Number 550-141-186/0703
22
Notes
1
2
3
Other manufacturers’ controls providing similar function may be used, if properly located and selected to handle boiler
evaporative capacity. Weil-McLain does not recommend using McDonnell & Miller Model 157 or 193.
Cannot be used as backup water level controls.
When pump control is used with feed water tank, install pump control on boiler and makeup water feeder on tank. Use
separate low water cutoff on boiler when backup is needed. Do not install combination low water cutoff and feeder as
backup control on boiler. Feeder will operate before pump control operates.
6
Install boiler controls
Controls
Relief valve
stem vertical
only
Table 4
Recommended locations for
steam boiler low water
cutoffs, water feeders and
pump controllers
(See Figure 23, page 23)
Install relief valve with spindle in vertical position. Relief valve discharge
piping must be piped near floor close to floor drain to eliminate potential
of severe burns. Do not pipe to any area where freezing could occur.
Failure to properly install, pipe and wire boiler controls may result in
severe damage to the boiler, building and personnel.
1. Install pressure operating and limit controls, water level controls, gauge glass and pressure
gauge as in
Figures 22 and 23
. Install relief valve(s), blowdown valve and other items as
given in
Figures 11a or 11b
, pages 12 and 13.
2. Install water level control(s) as shown in
Figures 22 and 23
and
Table 4
, below. If water
level control to be used is not shown in the table, install according to manufacturer’s
instructions.
Steam boiler
controls
1. Install controls in the tappings given in
Figures 11a or 11b
, pages 12 and 13.
2. Low water cutoff for a water boiler:
a. Must be installed on any water boiler if the boiler is located above radiation level.
b. May be required on water boilers by certain state, local or territorial codes or insurance
companies.
3. If a low water cutoff is used on a water boiler, use a control designed especially for water
installation. See control tapping locations in
Figures 11a and 11b
, pages 12 and 13, for
location, or install in piping above boiler.
4. Dual limit control settings:
a. Low — set according to design requirements.
b. High — 20
o
higher than low limit, 240
o
F maximum.
5. Install optional controls per control manufacturer's instructions.
Water boiler controls
Location 1
A
Location 2
B
Primary water level control
(Note 1)
Casting line height
(above bottom of
gauge glass)
First backup water level
control (Note 1)
Casting line height
(above bottom of
gauge glass)
61,63
1"
--
--
150S-MD, 93 (Notes 2 & 3)
2
3
/
8
"
--
--
51-2 and 51-S-2 (Note 2)
3
5
/
8
"
--
--
61 and 63
1
1
/
2
"
61 and 63
1
/
2
"
150S-MD, 93 (Notes 2 & 3)
2
3
/
8
"
61 and 63
1
/
2
"
51-2 and 51-S-2 (Note 2)
3
5
/
8
"
61 and 63
1
/
2
"
