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Old 12-11-2010, 02:38 PM   #1
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Need help fast please re hydronic boiler water supply and backflow


Stupid me left my garage door open yesterday for about 4 hours during minus 15C weather without having the garage furnace on. In my garage I have my "open" hot water heating boiler along with major 1/2" copper piping running all over the place. After 4 hours I by chance was in the area and saw frozen water on top of the pipes. I instantly closed the garage door and fired up the garage furnace. Sure enough about 10 minutes later one pipe started to spray water everywhere. Fortunately a shutoff was right in front and that stopped the major leak. Unfortunately the damage done was the line to the hot water heating boiler along with the inline backflow.

Called a plumber and he quickly replaced the section of damaged pipe but bypassed the backflow until I get a new one (so the boiler would still have a water supply)

So my questions are:

1) plumber said the backflow is only a rare precaution if the water pressure from boiler is so great that it pushes back, but said this is really rare and thus removal temporarily should not be a problem??? But I've heard that when you turn on taps they suck water and this suction can come from any water source (including my boiler without the backflow). Can someone comment on this???

2) plumber also said that the boiler uses constant water circulation once full, and thus really does not need a water supply line to be kept on. He said if I was concerned due to no backflow to just turn off the water supply (the same shutoff valve I originally used) and that the boiler would be fine as it is already full with all the water it needs. Again need comments on this???

3) the damaged backflow I have is a Watts 009 QT 1/2" which is quite a large (and expensive) unit with 4 test valves on top. Looked on ebay and saw many smaller and cheaper 1/2" backflows, many that do not have test valves or if so maybe one. Can someone let me know if any backflow is fine, or whether I need a larger unit like the Watts. If anyone will do, curious why the original builder would have used the expensive Watts vs a small/cheap unit????

I do plan to replace the backflow, but need to know how urgent it is, and in the meantime do I turn off the water supply to the boiler or if boiler absolutely needs a constant water supply what are the odds of contaminating my potable ater.

Thanks

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Old 12-11-2010, 02:50 PM   #2
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Need help fast please re hydronic boiler water supply and backflow


do you want to drink/eat the water from your furnace? Didn't think so. A RP backflow assembly is absolutely necessary, a gate valve is not sufficient protection. What if the valve has a slow leak thru the gate? Backflow is not as rare as you'd think, I'd get a new one in ASAP. Also, make sure it has the test cocks on it, no way to get it tested to verify operation without them

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Old 12-11-2010, 03:56 PM   #3
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Need help fast please re hydronic boiler water supply and backflow


You can use a Watts 007. You do not need an rpz. It really depends on the code you are under. In Michigan you can use the 007, unless you are a high contamination hazard. In that case you will need an rpz unit. The plumber is correct, you can limp by temporarily, I stress very temporarily, I'm surprised he didn't have a backflow device with him.
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Old 12-11-2010, 05:08 PM   #4
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Need help fast please re hydronic boiler water supply and backflow


I have a similar boiler setup. My boiler was installed in 1959, with no backflow preventer, which was standard practice in 1959. The boiler pressure is maintained at about 15 psi by the pressure reducing fill valve. whereas the pressure in the lines is typically a minimum of 30 psi (I am on well water, pressure varies from 30 to 50 psi). I have lived in this house for 20 years, the lack of a backflow preventer failed to kill me.

Recently I replaced the fill valve, and when I did I added a Watts backflow preventer with a clean out port and a test port. This valve cost about $50, and of course as noted a backflow preventer is not code. I also have a ball valve shutoff upstream of the backflow preventer.

I am not so skeptical about the ball valves, I think in a pinch they would be OK. Also, backflow can certainly occur, but only if the pressure in the boiler exceeds the pressure in the lines, which will only happen if the boiler pressure spikes at the same time the water pressure in the lines drops. This is an unlikely occurrence. To be safe, you do not have to drink water until the backflow preventer is in place, use bottled water. As for bathing, I would not be too concerned about bathing in water that has a small percentage of boiler water in it.

I believe your plumber is correct. As for needing a four port valve, I don't know what all the ports are for, but I would go with what the plumber suggests, sounds like he is knowledgeable and certainly is familiar with local codes.
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Old 12-11-2010, 11:27 PM   #5
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Need help fast please re hydronic boiler water supply and backflow


Trust your plumber, he gave you correct advice. Though a backflow preventer is required and even desired, they were not code mandated until about 20 years or so. Boilers typically operate at 12-15 lbs pressure so your house pressure would have to drop below that before backflow can occur, so relax and wait for the new one to come in. In the meantime, look into antifreezeing the system. short money for big insurance.
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Old 12-12-2010, 08:13 AM   #6
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Need help fast please re hydronic boiler water supply and backflow


I agree with posts #3, 4, 5.
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Old 12-12-2010, 09:42 AM   #7
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Need help fast please re hydronic boiler water supply and backflow


Quote:
do you want to drink/eat the water from your furnace? Didn't think so. A RP backflow assembly is absolutely necessary, a gate valve is not sufficient protection. What if the valve has a slow leak thru the gate? Backflow is not as rare as you'd think, I'd get a new one in ASAP.
Ayuh,... The boiler runs at 12 to 25psi,...
Domestic water supplies run 40 to 60psi, or More....

I agree with the above posters,...
The odds of a backflow are nearly Non-existent...
The quote above is from an alarmist...

Last edited by Bondo; 12-12-2010 at 09:44 AM.
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Old 12-12-2010, 10:39 AM   #8
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Need help fast please re hydronic boiler water supply and backflow


At least put in a small, cheap dual check valve. Where I'm from, backflow preventors are code. No alarmistness intended, but to not have one is stupid. Period.
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Old 12-13-2010, 06:32 AM   #9
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Need help fast please re hydronic boiler water supply and backflow


Where I am from there is a main back flow preventer on the incoming water supply so I would put the cheapest one I could find on the water supply to the heater. Besides from what the experts say the Supply Water Auto Valve to the Heater should have a manual water valve that stays closed all the time unless water is needed.
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Old 12-21-2010, 11:58 AM   #10
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Need help fast please re hydronic boiler water supply and backflow


Quote:
Originally Posted by Work4living View Post
You can use a Watts 007. You do not need an rpz. It really depends on the code you are under. In Michigan you can use the 007, unless you are a high contamination hazard. In that case you will need an rpz unit. The plumber is correct, you can limp by temporarily, I stress very temporarily, I'm surprised he didn't have a backflow device with him.

Talk about flip-flopping all over the place!

Don't tell someone what he can or can't use unless you know the code(s) of where the OP is living under. We don't have a location. What we do know is that the original backflow assembly is a Watts 009 - an RPZ. I willing to bet that if an RPZ was installed in the first place, the codes that the OP is living under needs and RPZ.

And by the way, a boiler is a high contamination hazard. As for having a backflow assembly with him – How many do you figure that he should keep in stock? Normally I service clients that have ”, ”, 1”, 1 ”, 2”, 3”, and 4” and a couple of 8” RPZ’s and double check backflow assemblies (DCVA)’s. The OP’s plumber probably does the same. Should we keep at least 16 backflow assemblies in stock in our truck for the rare time that someone leaves a garage door open and freezes the unit? Most of the time a backflow assembly repair consists of replacing the rubber kit and not the entire unit.

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Old 12-21-2010, 12:13 PM   #11
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Need help fast please re hydronic boiler water supply and backflow


Quote:
Originally Posted by the_man View Post
do you want to drink/eat the water from your furnace? Didn't think so. A RP backflow assembly is absolutely necessary, a gate valve is not sufficient protection. What if the valve has a slow leak thru the gate? Backflow is not as rare as you'd think, I'd get a new one in ASAP. Also, make sure it has the test cocks on it, no way to get it tested to verify operation without them

Quote:
Originally Posted by Bondo View Post
Ayuh,... The boiler runs at 12 to 25psi,...
Quote:
Originally Posted by Bondo View Post
Domestic water supplies run 40 to 60psi, or More....

I agree with the above posters,...
The odds of a backflow are nearly Non-existent...
The quote above is from an alarmist...
Another one that lives a full and rich fantasy life.

If there was absolutely no chance of cross connection and or contamination, then why do you figure that there was a backflow assembly (RPZ) on the boiler to start with? For good looks? How about for safety and plumbing code?

In a perfect world the pressures of the city water supply would always be greater than the boiler supply, but unfortunately we don't live in a perfect world. Pressures can and do drop. A water main break, or even something as simple as the fire department connecting to a hydrant in the area can cause a massive water pressure drop. This can and will cause the water to backflow in the entire system. A properly functioning and maintained backflow assembly will stop any contaminated or polluted water from entering the potable water supply.

the_man is the only on of you guys that actually came up with the correct and safe answer.

Get this corrected properly, and don't try to band-aid it to try to save some money DIY'ing

Mick

Last edited by Water Guy; 12-21-2010 at 12:17 PM.
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Old 12-21-2010, 12:24 PM   #12
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Need help fast please re hydronic boiler water supply and backflow


Quote:
Originally Posted by plumber666 View Post
At least put in a small, cheap dual check valve. Where I'm from, backflow preventors are code. No alarmistness intended, but to not have one is stupid. Period.


Replace the damaged unit with a properly functioning unit that is to code, don't replace it with a non-testable inferior unit.

plumber666, is correct about the, "Where I'm from, backflow preventors are code. No alarmistness intended, but to not have one is stupid. Period." part, but follow your code. It will most likely state that you need an RPZ, and is has to be tested upon installation, when repaired, moved, and at least annually.

And plumber666, I am in the same province as you are, and an RPZ is needed for a boiler not a dual check.

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Old 12-21-2010, 12:41 PM   #13
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Need help fast please re hydronic boiler water supply and backflow


Quote:
Originally Posted by COLDIRON View Post
Where I am from there is a main back flow preventer on the incoming water supply so I would put the cheapest one I could find on the water supply to the heater. Besides from what the experts say the Supply Water Auto Valve to the Heater should have a manual water valve that stays closed all the time unless water is needed.
Another valuable bit of advise from a well intended but mis-informed DIY'er.

Follow your municipal or water department plumbing code. The RPZ that is on the boiller supply line is there for a reason. Keep it there, replace it or repair it if it has failed, and keep it maintained and tested.

COLDIRON, you are correct in the fact that the supply line should stay closed unless water is needed, but does that mean that no one will accidently open it (not knowing what it's there for) and leave it open? Or, open it to fil the boilerl, and accidently leave it open. Will the seals in the valve never ever leak? You're banking on a lot of "what if's, and "It won't happen to me", to go with a cheap non-plumbing-code DIY solution. Over the years I have read hundreds of reports of backflow incidents and potable water being contaminated because someone accidently left the wrong valve open and them not having a properly functioning backflow assembly in the proper place.

Mick
Certified backflow assembly tester.
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Old 12-21-2010, 12:44 PM   #14
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Need help fast please re hydronic boiler water supply and backflow


Quote:
Originally Posted by Daniel Holzman View Post
As for needing a four port valve, I don't know what all the ports are for, but I would go with what the plumber suggests, sounds like he is knowledgeable and certainly is familiar with local codes.
It's not a four port valve, it's four ports on the valve. The four ports are testcocks so that the backflow assembly tester can connect to the RPZ to run the annual test.

Mick
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Old 12-21-2010, 02:45 PM   #15
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Need help fast please re hydronic boiler water supply and backflow


Hey water guy we know you are an expert at Back flow but take a chill pill and go easy on us guys that know something about the subject but are not experts , REMEMBER this is a DIY site and don't be an alarmist the OP will get it. I have seen hundreds of boilers and heaters without back flows not saying that's OK just saying. I am a certified HVAC pro but I try not to bash people for asking questions, notice I said try.
Or try to bash other responders answers back to OP. Try.

PS: A lot of houses have a main Back flow to the city water system.

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