Backflow preventer

Steam_Starter

Can someone suggest a backflow preventer for my 1/2" copper boiler water makeup line.

Town wants me to install one...

Steam_Starter

Oh and I am located in NJ....

Jamie Hall

Watts 9D

Steam_Starter

Thats what I am reading. Thanks, JH.

hot_rod

Do they require a testable style? If so that model will not pass.

Steam_Starter

What model if testable? I cant get a straight answer out of the code officials. These are the same people who took 21 days to approve my permit.

JUGHNE

An expensive one.....and who will test it every year and what will that cost? Then who will police that testing?
IIWM, I would just put that Watts 9D in and nicely pipe the drain/vent down to the floor. It looks pretty impressive to an inspector who doesn't know the difference.

Steam_Starter

Thats it then. Thanks all.

JUGHNE

My only awareness of this is that my hospital asked me to do a water piping survey for Legionella prevention planning.
Having changed the water heaters out I was somewhat familiar with the boiler room.
They had 2 steam LWCO feeders, one HWH glycol system connection and the feeder pump pit all connected to the domestic water supply. There were only check valves on the first 3 items and none on the feeder pump pit where the boiler chemicals were added!

The AHJ was the city water department. It just so happened that the State Rural water safety instructor was in town also.
We had a meeting in the boiler room and I was informed that all those 4 devices need testable BFD's installed. It turned out that a single 1 1/4" line fed all of them and a Watts RPZ was installed ahead of them all. Fairly simple and the local city water man can test it yearly for a very modest fee.

To me the Watts 9d would be adequate but the State does require the testable RPZ here. Also considering the high profile for hospital use I understand the risk and made no argument.

Mark Eatherton

The Watts 9-d is a double check with intermediate atmospheric vent, and it doesn't meet the requirements for commercial installations, which have to be a reduced pressure principle back flow preventer. The 9-d can be set up to be tested, but it is considered inadequate for commercial/institutional properties.

Here in Colorado, if we can prove that there is no physical connection between the potable water system and the heating system (using either a PIG or a tank/pumped make up tank) then you needn't install a back flow preventer. A non testable vacuum breaker/back flow preventer on the drain valve used to fill these devices is all thats required, and it doesn't require annual testing/inspection.

Truth be known, I've never seen in ANY mechanical/plumbing code the requirement for a "make up water connection" to the heating system. If you don't have one, then you don't have to protect it.

I've never understood their reasoning that its OK for residential applications to have a lesser quality BFP than it is for a commercial property...

There are ways around it...

ME

Steam_Starter

I just find it silly. Ball valve is used for shut-off and is obviously only open when I fill, which is rarely during the season. I don't have / need an auto fill. SO basically unless I open the fill valve there is fixed isolation between the boiler and the feed line.

However, it is what it is....

Mark Eatherton

Steam_Starter said:

I just find it silly. Ball valve is used for shut-off and is obviously only open when I fill, which is rarely during the season. I don't have / need an auto fill. SO basically unless I open the fill valve there is fixed isolation between the boiler and the feed line.
However, it is what it is....

The AHJ has to look at it as though the homeowner has their system set up for automatic operation. Truth be known, it would be hard for steam to cause contamination of a potable water system, but if there is 1 chance in a million, they HAVE to cover.

The BIGGEST problem is that most inspectors do not know what they are looking at (a boiler is a boiler is a boiler) so they enforce the worst case scenario, because they do not know any better. To their credit, there are a FEW good inspectors out there that know.

ME

Dave0176

Here in NJ it is required for steam boilers too. Years ago the old swing check would suffice but now inspectors want a backflow.

SuperTech

If I had a dollar for every time I saw an unsafe or malfunctioning piece of equipment that the inspector said was fine.....a few good inspectors is right Mark, a very few.

CLamb

Does anyone have a code citation for this?

Jamie Hall

It's in the old National Plumbing Code -- but I have temporarily misplaced my copy...

I do remember the reasoning, though, and it may still be applicable: while the possibility of a steam boiler operating at say 1 psi backflowing into a water supply does look negligible (ditto for, say, a bathtub -- which requires an air gap) -- it really isn't. There are two scenarios, both of which I have seen -- while not as a regular occurrence, a few times. The first, and more common, is a fire with a pumper draughting from a nearby hydrant. That pumper can quite easily and often does pull the water pressure in the mains in the vicinity to below atmospheric -- sometimes well below. The mains pressure can be as low as -10 to -12 psi gauge. The other is a pump failure in some water supplies, which can lead to below atmospheric pressure in the mains until someone can get to fix it or adjust

JUGHNE

It happened to my boiler. The 6" main in front of my house had a bad tapping for the neighbor. They could shut off each end of the main to isolate it. When they removed the defective corporation stop (tap) the water drained out of the 6" main.

Later I noticed my boiler low on water. The draining water out of the main had syphoned water out of the boiler. I had only the PRV on the feeder. ( I was told this would prevent back flow....not so).
I now have a double check device on the water feeder, added a LWCO and keep the water supply valve closed.

Now for fire pumpers, we use soft hose with double 2 1/2" hoses connected to the hydrant. They get pretty squishy when you stand on them as you run the pumper to pretty good volume. (that is a high tech test to tell you that you are drawing too much water) we may have the pumper up to 250' from the hydrant. We are drawing a lot of water towards that hydrant.
Our mains are connected in loops to feed from both directions but somewhere depending upon piping etc there could be a near vacuum produced for some houses. I doubt if we get any part of the mains into a vacuum but certainly could go near zero. So your 12 PSI heating system could back flow into the domestic water in that case. Or your water heater if on the first floor.

Now if a car breaks off a hydrant the effect would be worse.
The only one of these I had to deal with was lucky as it had a break away control rod and the water stayed in the pipes.
(It did not gusher up as seen in the movies)
Fire hydrants are just like a yard hydrant in the control rod operates the water valve well below the frost/freeze line.
They also have a drain down port to empty the hydrant when shut off.

Gsmith

from the 2018 International Residential Building Code:
P2902.5 Protection of potable water connections. Connections
to the potable water shall conform to Sections
P2902.5.1 through P2902.5.5.
P2902.5.1 Connections to boilers. Where chemicals will
not be introduced into a boiler, the potable water supply to
the boiler shall be protected from the boiler by a backflow
preventer with an intermediate atmospheric vent complying
with ASSE 1012 or CSA B64.3. Where chemicals will
be introduced into a boiler, the potable water supply to the
boiler shall be protected from the boiler by an air gap or a
reduced pressure principle backflow prevention assembly
complying with ASSE 1013, CSA B64.4 or AWWA
C511.

Mark Eatherton

The UPC and UMC state basically the same thing, tho not verbatim.

ME

STEAM DOCTOR

Got to ask. What is wrong with boiler water if there are no chemicals. Obviously doesn't taste too great. Is it a health hazard? I have a buddy who's helper drank some steam boiler water just for kicks. Guy was a bit nutty.

STEAM DOCTOR

Keeping in mind that boiler water will be diluted under backflo conditions

Gsmith

Ours is (usually) not to reason why--on code issues.

Jamie Hall

Nothing wrong with boiler water, @STEAM DOCTOR -- if there are no chemicals. Big if. Considering the range of chemicals out there which are touted for fixing all the problems in the world, and which are readily available to the homeowner or clueless tech., and considering the toxicity of some of them... would you, as the supplier of water to your community, wish to guarantee that the water you supply would be safe? Not me... sorry.

JUGHNE

If your boiler does not ever need water supplied thru the PRV valve then that line would be considered a "dead end " or dormant pipe sitting with old water in it. Some things can grow in dead end piping.
If you had the scenario that happened to my boiler as posted above, then that stagnant water would be drawn into your pipes and possibly out into the main where it could be fruitful and multiply, so to speak.

Steam_Starter

WOW. What did I start here? I have to say I love the vigorous conversations and knowledge here that everyone brings.

Putting in the BFP Sunday. I’ll put up a pic or two for critique.

Steam_Starter

Well it’s in. My sweating job is not great. Way out of practice. But it’s in....

JUGHNE

Look good, let us know if it passes.

Steam_Starter

Will do. Inspections are on Friday 4/20. Will update then.

hot_rod

does the installation manual allow vertical installation? Some brands suggest horizontal only.

Steam_Starter

Spec sheet calls out vertical or horizontal installation.

Steam_Starter

Sorry for the late reply.

Inspector came and went. No issues. I asked why it is needed and he said "actually in your case it's really not needed. You do have an auto-feeder but we can't selectively apply the code."

He did like my 3" dropped header, though...

Leonard

Other issue is boiler "water" could be antifreeze. Neighbor who went to florida for the winters changed it to antifreeze so he could leave house unheated.

Here in NH don't think backflow preventer is required for single family houses unless have outside underground lawn sprinklers/piping. Strange because a vac in water line might be able to pull water back from a toilet tank that had been filling, oh well politics.....

But preventer is required for restaurants. Here city water dept comes in to test restaurant's preventer I think every 6 or 12 months and it's charged for on the quarterly water bill. On ours' there's 3 test ports and need to have good shut off valves before and after preventer so can leak pressure test it.