CSD-1 and check valves

Gordo

There appears to be a disconnect between CSD-1 and most plumbing codes with regard to backflow prevention in the water supply lines to a steam boiler. CSD-1 calls for a check valve on the water feed line to a steam boiler. Installing a RPZ does not cut it with the boiler inspector, he wants a check valve. If there there is chemical treatment to the boiler, the plumbing inspector wants an RPZ in the line. Most qualified plumbers regard the check valve as an expensive coupling as far as its effectiveness as a backflow preventor is concerned. Any thoughts?

Dana

In Massachusettes backflows are required on steam boilers with auto. feeds only. If there is no auto. feed, the fill valve is considered closed. Watts 9D-M3 are accepted for this as well as hydronic systems. It's a backflow preventor with intermediate atmospheric vent. Don't know the code you are quoting though. Hope this helps.

Gordo

CSD-1 and backflow

In Maryland, a Watts 9D-M3 is ok for a residential boiler. It's not acceptable in most areas of the Old Line State as a BFP on a commercial boiler. There, only a RPZ (two independently acting check valves with a relief zone between them and testable and rebuildable) is acceptable to the plumbing inspector. The boiler inspector does not care that the RPZ is designed for high hazard backflow prevention. CSD-1 tells him that a check valve must be installed and that's that. Logic and reason is left outside the boiler room door. A 9D-M3 or a RPZ is simply an ugly length of pipe as far as he is concerned. Auto feed or no auto feed, a BFP is needed. To the plumbing inspector, a check valve is a sick joke as a BFP. This is just my insignificant opinion.