Which comes first . . . backflow or reducer

Andruid_2

I've seen the relief valve in a backflow preventer discharge maybe three times in my life. I chalked it up to crap getting into the second check valve and preventing a good seat. But lately I've been wondering if the pressure coming into the backflow preventer matters. Those times of discharge were also times of no water pressure in the house. I believe I read one time, that the pressure reducer belongs AFTER the backflow preventer. Now my supervisor says to put the pressure reducer BEFORE the backflow preventer (only because the Watts 009 says it's a "reduced pressure zone" backflow preventer). I think the Watts 009 is rated for 175psi water pressure. If a house has higher water pressure than this, there are bigger problems to deal with than a broken backflow preventer.

So . . . are there logical explanations for which comes first . . . backflow or reducer?

Lyle C

Backflow

As you said "Those times of discharge were also times of no water pressure in the house." The backflow was doing its job there was more pressure in the boiler than the home piping. When it discharged it stopped the water from backing into the domestic water. If the BF is placed after the pressure educing valve. It is in a low pressure zone it may dribble when ever the boiler fires just due to exspantion .The reason a 009 is called reduced pressure zone.Is that after passing through the first check the pressure will be a pound less.

HAPLUMBER

i never saw a house that had 175 ibs going into it the only pressure i ever saw was 100lbs and that was going into a 18 story building which had a 3inch main. also most fitting ARE RATED FOR 125 ILBS SO I DOUBT THERE WILL ANY PROBLEMS WITH ANYTHING OVER 175 LBS

Steverino

Info. courtesy of David Yates...

> I've seen the relief valve in a backflow

> preventer discharge maybe three times in my life.

> I chalked it up to crap getting into the second

> check valve and preventing a good seat. But

> lately I've been wondering if the pressure coming

> into the backflow preventer matters. Those times

> of discharge were also times of no water pressure

> in the house. I believe I read one time, that

> the pressure reducer belongs AFTER the backflow

> preventer. Now my supervisor says to put the

> pressure reducer BEFORE the backflow preventer

> (only because the Watts 009 says it's a "reduced

> pressure zone" backflow preventer). I think the

> Watts 009 is rated for 175psi water pressure. If

> a house has higher water pressure than this,

> there are bigger problems to deal with than a

> broken backflow preventer.

>

> So . . . are there

> logical explanations for which comes first . . .

> backflow or reducer?



http://forums.invision.net/Thread.cfm?CFApp=2&Thread_ID=45971&mc=14#Message321969
This may take care of your problem.

Steverino

courtesy of david Yates:

> I've seen the relief valve in a backflow

> preventer discharge maybe three times in my life.

> I chalked it up to crap getting into the second

> check valve and preventing a good seat. But

> lately I've been wondering if the pressure coming

> into the backflow preventer matters. Those times

> of discharge were also times of no water pressure

> in the house. I believe I read one time, that

> the pressure reducer belongs AFTER the backflow

> preventer. Now my supervisor says to put the

> pressure reducer BEFORE the backflow preventer

> (only because the Watts 009 says it's a "reduced

> pressure zone" backflow preventer). I think the

> Watts 009 is rated for 175psi water pressure. If

> a house has higher water pressure than this,

> there are bigger problems to deal with than a

> broken backflow preventer.

>

> So . . . are there

> logical explanations for which comes first . . .

> backflow or reducer?

Steverino

courtesy of David Yates:

have a look at the link below:
http://forums.invision.net/Thread.cfm?CFApp=2&Thread_ID=45971&mc=14

Steve M_2

Backflow is first

The backflow is the 1st valve inline on your makeup water and then the regulator or fill valve. If you install the fill valve first and then the backflow, you isolate the fill valve and it can't read the pressure of the system that is determined by your air charge on your bladder of your expansion tank. The backflow preventer is essentially a double check vavle, it keeps the boiler water seperate from the potable and it keeps water in the boiler in case of a break on the house side or water main from the street. This is the most common error I see on systems that I service.

Steve