Blow air through PVB?

[johnboy37]

I just had a plumber put in a backflow for me, they put in a Watts 800. They put the connection for winterization upstream of the PVB, and said that we can just blow out the system through the PVB to winterize. They said "they just did a 1.4 million dollar home and they always do it this way".

I was under the impression that I should have a blowout tap after the downstream valve of the pvb, then I could hook up the air there and blow the system out with the downstream valve closed, so the air doesn't blow through the PVB.

Who was right?

[Wet_Boots]

With your own home compressor, no worries - with a hot jackhamer compressor blowing 250-degree air, worries

[mitchgo]

Having a blow out installed prior to the back flow assembly is illegal and is a form of cross contamination.

Up here when we see this.. We always recommend to take it out and install it down stream of the bfp

[bx24]

Originally Posted by johnboy37

I just had a plumber put in a backflow for me, they put in a Watts 800. They put the connection for winterization upstream of the PVB, and said that we can just blow out the system through the PVB to winterize. They said "they just did a 1.4 million dollar home and they always do it this way".

I was under the impression that I should have a blowout tap after the downstream valve of the pvb, then I could hook up the air there and blow the system out with the downstream valve closed, so the air doesn't blow through the PVB.

Who was right?

Depends on your state. In MA/CT we blow out AT the PVB for winters (if no unions to remove). Some install a boiler drain before and use that or use the test ports....

[Mike Leary]

I never blew through any assembly, used a 7 psi bicycle pump instead. I suppose a unit could be blown if the operator had a compressor that could be dialed-down, but that seems like a waste of time, plus the possibility of melting the the checks. I installed a quick-couple just south of the backflow with brass fittings to absorb the heat of the compressor and blew my heart out with this method for thirty years.

[Wet_Boots]

Originally Posted by mitchgo

Having a blow out installed prior to the back flow assembly is illegal and is a form of cross contamination.

Up here when we see this.. We always recommend to take it out and install it down stream of the bfp

Try not to devalue your contributions by assuming your local customs are the law of the land. Besides, the upstream blowout valve is only an opportunity for someone to introduce contamination, and that is a different animal than an actual cross-connection.

[mitchgo]

Hence why I said Form of cross contamination

Hey I follow the codes of good ol California. Besides.. Back flow preventors do not like air which causes the checks to slam about and heat up/ break/melt

Just the other day I went out to a new customer for a stuck valve. When I took apart the valve. I found a part of a broken spring from the back flow assembly

[Wet_Boots]

It is not a form of cross-connection period, any more than upstream testcocks on a backflow preventer are a form of cross-connection.

(there is no such thing as "cross-contamination")

[mitchgo]

Well I be-sure to be like this guy and then tell you it's not a cross contamination.. k?

[Wet_Boots]

There is "cross-connection" and there is "contamination" - there is no "cross-contamination"