Lennox International Inc. GWB9-050IH-2 User Manual

High Effi ciency Gas-Fired Boiler

Follow these instructions to prevent damage to 

boiler’s heat exchanger caused by inadequate 

dielectric isolation, incorrect water treatment or 

antifreeze application. Failure to comply could result 

in death or serious injury.

  

• Install boiler so gas ignition system components are 

protected from water (dripping, spraying, rain, etc) 

during appliance operation and service (circulator re-

placement, etc).

• DIELECTRIC ISOLATION 

Two (2) 1-1/4” X 1-1/4” Female to female dielectric 

isolation unions are shipped loose in boiler parts bag. 

Install Dielectric Isolation unions at boiler supply line 

and return line. Install isolation fi ttings nearest boiler 

prior to system piping connections.

MUST be applied for ALL aluminum series high 

effi ciency gas-fi red boilers using antifreeze 

protection.