# Loud Check Valve (Copper Swing-check)



## Ishmael (Dec 9, 2009)

I got a call from the owner of a house I recently plumbed, complaining that there was a loud banging every time he used any fixture. When I checked it out, I found it's the copper swing check(s) leading into the water heater. Recirc. line with its own swing check tees in downstream of the swing check on the cold water supply before entering the water heater (Eternal GU195S). So I took out the 3/4" vacuum breaker (still required here in MA) and put in a brass tee that allowed for the installation of a thermal expansion tank, and reinstallation of the vacuum breaker.

It did nothing to quiet the noise, so now I'm not quite sure how to remedy it - other than to tell him not to shut things off so abruptly! Would spring checks work better? Is there something else I could/should do? Anyone...anyone...Buehler...


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## bct p&h (Jan 19, 2013)

If I understand you correctly you have a swing check on the recirc AND the cold water inlet to the heater? If so, by Massachusetts code you need to drill a hole in the paddle of the check on the cold water inlet. That should take care of the slamming problem along with any code violation.


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## 422 plumber (Jul 31, 2008)

I have swapped swings for springs on process applications, not on domestic, and it stopped the banging.


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## Ishmael (Dec 9, 2009)

bct p&h said:


> If I understand you correctly you have a swing check on the recirc AND the cold water inlet to the heater? If so, by Massachusetts code you need to drill a hole in the paddle of the check on the cold water inlet. That should take care of the slamming problem along with any code violation.


I thought about doing that, but had no idea it was a code requirement. I'll have to look it up. Any idea what size hole (it's a 1" check valve); I'm guessing 1/8", or 3/16"?

*Edited to add:* I just found it: *Section 10.14(9)(e)(2):*

_Thermal check valves that have a minimum 1/8" diameter hole drilled in the clapper may be permitted. A thermal expansion tank may be required or necessary on any cold water supply system where installation of backflow prevention devices or pressure reducing valves would create a closed system and constitute an operating hazard or nuisance._

Thanks for that bct p&h! Learn something new every day. Hopefully that will resolve the issue.


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## rjbphd (Feb 5, 2010)

What's the purpose of a check valve with a hole in it??? Don't make *&^%$# sense, get rid of the check on the recirc line.. check ur pressure tank on cold water line... and u said, u re piped the home, did u install pre charged air chambers at fixtures???


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## Ishmael (Dec 9, 2009)

rjbphd said:


> What's the purpose of a check valve with a hole in it??? Don't make *&^%$# sense, get rid of the check on the recirc line.. check ur pressure tank on cold water line... and u said, u re piped the home, did u install pre charged air chambers at fixtures???


It does seem to defeat the purpose of the check valve, but it's code so that's what I'll do. It's only an 1/8" hole, so I don't think it's going to cause an issue in terms of the recirc pump forcing hot water through the cold water main. I'm just thinking it will dampen the movement of the clapper enough to prevent the slamming.

Eliminating the check valve on the recirc line would cause luke warm water out of the hot taps. No water hammer arrestors at the fixtures.


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## rjbphd (Feb 5, 2010)

Ishmael said:


> It does seem to defeat the purpose of the check valve, but it's code so that's what I'll do. It's only an 1/8" hole, so I don't think it's going to cause an issue in terms of the recirc pump forcing hot water through the cold water main. I'm just thinking it will dampen the movement of the clapper enough to prevent the slamming.
> 
> Eliminating the check valve on the recirc line would cause luke warm water out of the hot taps. No water hammer arrestors at the fixtures.


What??? Where did u tied the re circ line into??


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## Ishmael (Dec 9, 2009)

rjbphd said:


> What??? Where did u tied the re circ line into??


It's tied into the cold water supply to the water heater - hence the check valve on the cold water supply.


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## bct p&h (Jan 19, 2013)

The point of the check valve with the hole is there is still enough of the flapper there to stop enough of the hot water from the recirc from entering the cold side and causing hot water from coming out of the cold side of the fixtures but the ⅛" hole is enough to allow the expanding water from the heater a place to go in case the expansion tank ruptures. 
Now after that run on sentence...
I've had to add check valves on tanks before and the ⅛" hole in the flapper works. The last time was on some 100 gallon indirects in a public housing building. The engineer didn't have them on the specs but every morning, after low to no use, there would be 120 degree water coming out of the nearest toilets and cold side of faucets. The boiler side of the piping was designed for maximum use but when you have the heater just trying to recover from static loss it heats too quickly and had no where to go but the cold water piping. After adding the checks with the holes in the paddles there were no more issues. Hot stayed hot, cold stayed cold and the t&p didn't go off.


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## rjbphd (Feb 5, 2010)

Ishmael said:


> It's tied into the cold water supply to the water heater - hence the check valve on the cold water supply.


There's part of ur problem, wrong place to connect the return line...


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## Ishmael (Dec 9, 2009)

rjbphd said:


> There's part of ur problem, wrong place to connect the return line...


This is a wall-hung, tankless water heater piped per manufacturer's recommendation. There's really no place else it can be tied-in.


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## Ishmael (Dec 9, 2009)

Success! Thanks again.


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## Caduceus (Mar 1, 2012)

Please explain "Success" and what you did.

I've heard this 'drill a hole in the flapper' theory before and have seen the negative side of it's application.
When you drill a hole in the brass you have compromised the strength of the material and it will eventually crack and break sending pieces into the piping and appliance. The copy of the code shown stated that they are 'pemitted' not 'required' with a hole in them. By specifically pointing out that they are permitted may indicate that the practice of drilling the hole may have been questionable.
Additionally, if the hole is intended to be a method of allowing thermal expansion through, then it doubles the problem instead of solving it.
A thermal expansion tank or thermal expansion relief valve is to be installed between the check valve and the appliance (referring to tank units, not tankless).
As 422 said, if a swing check is problematic, it is best to replace with a spring check designed for residential potable water. 
A 'clacking' swing check is typically a sign of damage or build up in the valve, if it's old. On a new installation it may be caused by a conflict of pressure in the piping design causing turbulence, common when installed too close to a tee connection. That's where the spring check comes into play.


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## Caduceus (Mar 1, 2012)

Hind sight is 20/20. If I knew this was going to be a topic, I would have taken a picture of the swing check that I removed last year with the flapper broken in half down the middle of the hole that was drilled in it. It was just installed a year before.


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## 422 plumber (Jul 31, 2008)

I have removed quite a few swing checks from domestic hot water recirc systems at schools and restaurants that the flapper was just gone. I don't know what the root cause was, but most were 5-10 years old.

Sent from my iPhone using PlumbingZone


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## Ishmael (Dec 9, 2009)

Caduceus said:


> Please explain "Success" and what you did.
> 
> I've heard this 'drill a hole in the flapper' theory before and have seen the negative side of it's application.
> When you drill a hole in the brass you have compromised the strength of the material and it will eventually crack and break sending pieces into the piping and appliance. The copy of the code shown stated that they are 'pemitted' not 'required' with a hole in them. By specifically pointing out that they are permitted may indicate that the practice of drilling the hole may have been questionable.
> ...


 
MA code actually forbids the check valve on the cold water supply to the water heater unless you've got special permission from the State Board [Section 10.14(9)(e)(1)]. I think that's a bit of an anachronism because it clearly doesn't account for the installation I've described with the on-demand water heater - there's nowhere else the recirculation line can be tied-in, so the check valve is necessary. The code also allows some flexibility in that it will allow you to follow manufacturer's instructions even if it goes against some code requirement. In the code section I referenced above, The Board will begrudgingly allow the check valve IF the 1/8" hole is drilled into the clapper.

If that means the clapper fails next year, the HO can take it up with the State Board; I'm covered. And in the meantime, the customer doesn't have to listen to a slamming check valve clapper.

I'll try spring checks next time.


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## bct p&h (Jan 19, 2013)

Even if a spring check is used, you'd still have to drill a hole in it per Massachusetts code.


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## Caduceus (Mar 1, 2012)

bct p&h said:


> Even if a spring check is used, you'd still have to drill a hole in it per Massachusetts code.


I'm really curious about this one. The last excerpt did not mention requiring one, only that they were permitted.
Could somebody copy something in print from the MA code that says that a drilled hole is required. I've never heard of or could imagine that a code would require you to tamper with a solid swing check or spring check to compromise the strength and usefulness of the appurtenance and actually create a problem. 

I could see if a manufacturer provided a hole cast into the product, but to modify by drilling? And look at what it creates; Ishmael essentially said " Hey, even if it's wrong, somebody in authority said it was right...not my problem."

So, c'mon all of you MA plumbers. Somebody has to have a copy that shows where it is required to have a hole in a check or spring valve and why.


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## Ishmael (Dec 9, 2009)

Caduceus said:


> I'm really curious about this one. The last excerpt did not mention requiring one, only that they were permitted.
> Could somebody copy something in print from the MA code that says that a drilled hole is required. I've never heard of or could imagine that a code would require you to tamper with a solid swing check or spring check to compromise the strength and usefulness of the appurtenance and actually create a problem.
> 
> I could see if a manufacturer provided a hole cast into the product, but to modify by drilling? And look at what it creates; Ishmael essentially said " Hey, even if it's wrong, somebody in authority said it was right...not my problem."
> ...


Here's the actual code section(s) verbatim: 

*Section 10.14(9)(e)(1)* - _A check valve shall not be installed in the cold water supply to any hot water heater or hot water storage tank, unless Special Permission has been granted by the Board._

*Section 10.14(9)(e)(2)* - _*Thermal check valves that have a minimum 1/8" hole drilled in the clapper are permitted*. A thermal expansion tank may be required or necessary on any cold water supply system where installation of Backflow Prevention Devices or pressure reducing valves would create a closed system and constitute an operating hazard or nuisance._

I think in my earlier posting of the 2nd section I wrote "_may be permitted_", but the actual verbiage is as it appears in this post - ("are permitted") After first saying check valves shall not be installed on the cold water supply to a water heater without "Special Permission", they qualify that by saying it's OK if - and only if - the hole is drilled in the clapper.

All I know is the HO is happy, and the installation (now) meets MA Code.


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## Caduceus (Mar 1, 2012)

bct p&h said:


> Even if a spring check is used, you'd still have to drill a hole in it per Massachusetts code.


It's just a curiosity thing, Ishmael. That's all. I'm not trying to get up anybody's butt on it. I have heard "It's required by code" for years and have posted before on forums how plumbing myths become codes.
Hearing that drilling a hole in a check valve being required by code sounds like one of those situations and I just wanted to see if a section could be provided.
If it's actually a code, so be it. It's not MY code. 

It's interesting learning about the differences in our trade as well as the similarities.


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