Weil-McLain Standing Pilot Cast Iron Gas Boiler CGA25SPDN User Manual

16

Part Number 550-101-009/0107

¾"

¾"

1"

1"

1 ¼"

1 ¼"

1 ½"

1 ½"

Note: The boiler supply and return connections, the return/ 

drain tee and the supply/gauge tee supplied with the 
boiler are 1¼” NPT. One of the circulator flanges sup-
plied with the boiler is 1¼”. The other circulator flange 
is the size of the recommended system piping shown 
above.

)F

 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 34 or 38, for wiring.

A 

 is required when boiler is installed above ra-

diation 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 in supply piping above boiler.

Use

 in cold water supply as required by local 

codes.

Install pressure/temperature gauge in tee on supply piping (as shown in 
drawing on page 3).

)NSTALL

, page 17, and the tag attached to the relief valve for manufacturer’s 

instructions.

See 

 (diaphragm-type or bladder-type expan-

sion tank) or 

 (closed-type expansion tank), 

and 

  below,  for near-boiler and single-zone 

systems designed for return water at least 130°F.
3EE

 

: 

Install boiler such that —

s

heating boiler. Use appropriate valves to prevent 
CHILLED

s

air handling units where they can be exposed to 
refrigerated air, use flow control valves or other au-
tomatic means to prevent gravity circulation during 
COOLING

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 3 for a typical instal-
lation. Pipe the expansion tank to the suction side of the 
circulator whenever possible. Install an air separator in 
THE

 and 

 show typical near-boiler 

piping connections. 

 

 

To avoid water damage or scalding due to relief valve   

operation:

s

. Terminate the discharge line to eliminate 

possibility of severe burns should the valve discharge.

s

 throughout its entire length.

s

 from the valve and terminate 

AT

s

, with a mate-

rial serviceable for temperatures of 375°F or greater.

 shall be installed between the relief valve and boiler, 

OR

 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.

 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.