Connect Piping - Water Boilers - Weil-McLain EG Manual

EG PEG EGH
• •
Connect piping – water boilers
General
Install the boiler jacket before connecting return piping. (Supply pipng can
be connected before or after jacket installation.) Connect controls after all
piping is connected.
If installation is to comply with ASME or Canadian requirements, an ad-
ditional high temperature limit is needed. Install control in supply piping
between boiler and isolation valve. Set second control to minimum 20 °F
above setpoint of first control. Maximum allowable setpoint is 240 °F. See
page 23 for wiring.
A low water cutoff device is required when boiler is installed above radia-
tion level or by certain state or local codes or insurance companies. Use
low water cutoff designed for water installations. Electrode probe-type
is recommended. Purchase and install in tee supply piping above boiler.
Use backflow check valve in cold water supply if required by local codes.
Near-boiler piping
Boiler connections
1. EG — Connect supply and return to left end.
2. EGH — Connect supply and return to same end, either left or right.
3. Plug all unused connections.
Systems operating at or above 130°F
1. See Table 6 and Figure 14 (diaphragm-type or bladder-type expansion
tank) or Figure 13 (closed-type expansion tank) on page 12 for near-
boiler piping for systems designed for return water at least 130 °F.
Low-temperature systems
1. See page 16 (Figures 16 and 17) for near-boiler piping for low-temper-
ature or high-volume systems.
2. See page 15 (Figure 15) for boilers used with refrigeration systems.
Relief valve
Install relief valve vertically in ¾" tapping on side of boiler. See the tag at-
tached to the relief valve for manufacturer's instructions.
To avoid water damage or scalding due to valve operation,
discharge line must be connected to relief valve outlet and
run to a safe place of disposal. Terminate the discharge line
to eliminate possibility of severe burns should the valve dis-
charge.
• Discharge line must be as short as possible and be the same size as
the valve discharge connection throughout its entire length.
• Discharge line must pitch downward from the valve and terminate
at least 6" above the floor drain where any discharge will be clearly
visible.
• The discharge line shall terminate plain, not threaded, with a material
serviceable for temperatures of 375 °F or greater.
• Do not pipe the discharge to any place where freezing could occur.
• No shutoff valve shall be installed between the relief valve and boiler,
or in the discharge line. Do not plug or place any obstruction in the
discharge line.
• Failure to comply with the above guidelines could result in failure of
the relief valve to operate, resulting in possibility of severe personal
injury, death or substantial property damage.
• Test the operation of the valve after filling and pressurizing system
by lifting the lever. Make sure the valve discharges freely. If the valve
fails to operate correctly, replace it with a new relief valve.
14
-
Gas firEd boilErs
— 4 —
sEriEs boilEr manual
Table 6
Minimum Recommended Pipe Sizes (for 20°F rise)
Boiler
Number
EG-30, 35
EG-40, 45, 50
EG-55, 65
EG-75
EGH-85-95
EGH-105–125
Note:
Circulator
The circulator is shipped loose (wiring pre-attached to
boiler) to allow you to locate it either in the return or
supply piping, as desired. See page 12 for a typical instal-
lation. Pipe the expansion tank to the suction side of the
circulator whenever possible. Install an air separator in
the supply piping. Connect the expansion tank to the air
separator only if the separator is on the suction side of
the circulator. Always install the system fill connection
at the same point as the expansion tank connection to
the system. Figures 13 and 14 show typical near-boiler
piping connections.
Expansion tank
Diaphragm-type or bladder-type tank — Figure 14
1. Ensure expansion tank size will handle boiler and
system water volume and temperature. Tank must
be located in boiler return piping as close to boiler
as possible, before inlet side of circulator. See tank
manufacturer's instructions for details.
2. Install an automatic air vent as shown.
Closed-type tank — Figure 13
1. Ensure expansion tank size will handle boiler and
system water volume and temperature. See tank
manufacturer's instructions for details.
2. Connect tank to ½" NPT tapping located behind
supply outlet, using ½" NPT piping. Pitch any
horizontal piping up towards tank 1 inch per 5 feet
of piping.
Water piping — multiple zone systems
Install system piping using either circulator zoning or
zone valve zoning. Install expansion tank on suction side
of system circulator. Always connect fill line only at the
expansion tank — never at another point in the system.
Minimum recommended pipe sizes
Forced-flow systems Gravity-flow systems
Supply Return Supply
"A" "B" "A"
1" 1" 1 ¹⁄₂"
1 ¹⁄₄" 1 ¹⁄₄" 2"
1 ¹⁄₂" 1 ¹⁄₂" 2 ¹⁄₂"
2" 2" 2 ¹⁄₂"
2" 2"
2 ¹⁄₂" 2 ¹⁄₂"
* All supply and return pipe sizes are based upon a 20°F
temperature rise through the boiler
Undersized expansion tanks cause system
water to be lost from relief valve and
makeup water to be added through fill
valve. Eventual section failure can result.
Part Number 550-110-639/0512
Return
"B"
1 ¹⁄₂"
2"
2 ¹⁄₂"
2 ¹⁄₂"