THREE eF COMMERCIAL GAS MODELS WITH RETURN CIRCULATION
UNION (3 PLS.) SHUT OFF VALVE (3 PLS.)
**INTAKE VENT PIPE (3 PLS.)
EXHAUST VENT PIPE (3 PLS.)
HOT WATER TEMPERATURE AND PRESSURE RELIEF VALVE (3 PLS.)
DRAIN OUTLET (3 PLS.)
DISCHARGE TUBE (3 PLS.) BACK-FLOW PREVENTER
SHUT OFF VALVE (3 PLS.)
CIRCULATOR SHUT OFF VALVE SYSTEM RETURN UNION (3 PLS.)
WATER SUPPLY
BACK-FLOW PREVENTER
THIS DRAWING SHOWS A SUGGESTED PIPING CONFIGURATION AND OTHER DEVICES; CHECK WITH LOCAL CODES AND ORDINANCES FOR ADDITIONAL REQUIREMENTS. *EXPANSION TANK RECOMMENDED TO MINIMIZE ANY PRESSURE BUILD UP IF THE WATER SUPPLY PIPING HAS A BACK-FLOW PREVENTER, CHECK VALVE OR WATER METER WITH A CHECK VALVE. **AIR INTAKE PIPE OPTIONAL.