Heating Helper

CHAPTER 2 - HOT WATER PIPING - RESIDENTIALSYSTEM PURGE IN LIEU OF AIR VENTSAPPLICATIONAny series loop piping, especially where system high points may beconcealed or venting is impractical. “System purge” is designed toremove air initially from the piping system, especially the high points.GUIDELINESAfter the initial removal of air it is important for the system to be able tohandle air that will develop when the system water is heated. Installationof an air scoop or an in-line airtrol at the boiler supply will benecessary to either vent the air from the system or direct the air to astandard expansion tank.A system purge is recommended only on Series Loop Installations.If other than non-ferrous baseboard is used, such as Base-Ray, theinterconnecting pipe will purge but vents must be placed on each freestanding assembly of Base-Ray.PROCEDURE1. Fill system with water. Isolate boiler by closing valves (B) and (C).2. Begin purge by opening first zone or loop. Next, open valve (A)(cold water supply). Finally and immediately, open hose bib (D)Once water flows freely, close the first zone or loop and then do thesame for the remaining zones or loops.A. Separate ½” C.W.S. with Globe valve or by-pass P.R.V.B. Ball valve: optional but preferredC. Ball valveD. Hose bib (for purging)E. Zone valves or ball valves39