Weil-McLain CG-4 - Page 6

Section III: Piping
1. Pipe as shown'in Figures 3 or 4.
a. Diaphragm-type expansion tank: Be sure tank pressure
and size will handle system pressure and water volume.
1) Fill pressure may be adjusted at tank for design con¬
ditions. Follow manufacturer’s instructions.
2) Additional tanks may be connected to tees in system
near boiler.
3) Install automatic air vent as shown in Figure 3.
b. Closed-type expansion tank: Size tank to system require¬
ments. Refer to tank manufacturer’s instructions.
1) Connect from V4" N.P.T. tapping (located behind sup¬
ply outlet) to expansion tank. Use Vi" piping. Any hor¬
izontal piping must pitch up towards tank 1" per 5
feet of piping.
2) Built-in air elimination system is provided. No addi¬
tional device is needed if tank is piped as shown in
Figure 4.
2. Use low water cut-off when:
a. boiler is located above radiation level.
b. required by certain state, local, or territorial codes or
insurance companies.
Use low water cut-off designed for water installations.
Electrode probe type may be located in tee in supply piping.
TO
SYSTEM
WATER
SUPPLY
CLOSED TYPE
EXPANSION TANK
CLOSED TYPE EXPANSION TANK PIPING
FIGURE 4
TABLE I - MINIMUM RECOMMENDED PIPE SIZES
Based on 20°F temperature drop between supply and return.
DIAPHRAGM TYPE
EXPANSION TANK PIPING
FIGURE 3
3. If the system is to comply with ASME or Canadian require¬
ments, an additional high temperature limit is needed.
Install control in supply piping between boiler and isolation
valve. Set second control to minimum 20°F above set point
of first control. Maximum allowable set point is 240°F. See
Control Supplement for wiring.
4. Verify relief valve is installed with spindle in vertical posi¬
tion.
WARNING
Relief valve discharge piping must be
piped near floor close to floor drain
to eliminate potential of severe
bums. Do not pipe to any area where
freezing could occur.
5. C onnect supply, return, and cold water fill piping. See Table
I for minimum recommended pipe sizes.