Water hammer after irrigation installed - help!

[JonLondon]

Before we has a small irrigation sprinkler installed at our home a couple of weeks ago, the only time I could hear any water hammer was if I opened an upper-floor faucet full force and slammed it shut - I would hear one thump that lasted a second in the bathroom itself.

Then we had an in-ground sprinkler installed, and now, if I flush a toilet at night (in a different bathroom off our bedroom), then run a faucet briefly, there is sometimes (but not always) a loud, groaning sound that lasts for about 10 seconds and comes from farther away. Also, two toilets that previously were running fine are now running long after they are flushed.

Our house is on city water with a psi about 78 at the street and a bit lower in the house. The water enters the house through a metre in the basement. The water runs up from the metre to near the basement ceiling and turns 90 degrees to run below the ceiling, all in 3/4" copper pipes. When the plumber attached the sprinkler to the water supply, he made a t-connection a few inches from the initial 90-turn, connecting the T to 1" plex which then runs almost straight 30 feet to an exterior wall, so the plex line is perpendicular but in the same plane as the main line. Outside the exterior wall the pipe runs up to a backflow preventer, then down beneath grade to a master valve.

I have not heard problems when the sprinklers are running but believe the problems are related to the sprinkler installation since they only appeared after the installation.

What might be wrong? How do I diagnose the problem? How can it be fixed?

Thanks for all and any suggestions.

Jon

 

[bathroomboy]

Jon, from the termination you have used I guess your from the states or Canada, your plumbing may be a little bit different from what we have in the uk, certainly your w/cs are different most are syphonic,the groaning sound you describe maybe the float valve washer, change this and it may cure the problem, thats usually the fault in the uk, hope this helps. Rob

 

[JonLondon]

Jon, from the termination you have used I guess your from the states or Canada, your plumbing may be a little bit different from what we have in the uk, certainly your w/cs are different most are syphonic,the groaning sound you describe maybe the float valve washer, change this and it may cure the problem, thats usually the fault in the uk, hope this helps. Rob

Thanks Rob.
You are correct -- I'm in Canada (and the other London). Which float valve washer are you talking about? The only new valve for the irrigation, is a solenoid valve.
Jon

 

[bathroomboy]

The float valve to fill the w/c cistern, on some uk valves they have a diaphram washer which with age tends to become sticky and causes a groaning noise as the cistern is filling, this is vibration being transmitted through the supplying pipework. Rob

 

[Puddle]

Does sound like the rubber washers on your w/c valves require replacing,they probablit dryed out when water was turned off to for sprinkler system to be installed
however if before you got a water hammer sound if tap turned off quick, you may also find a problem with the solinoid valve closing quickly

 

[Benfoord]

When alterations are made to any system it can show up problems that have been gradually getting worse. You've got about 5 bar pressure. Install a PRV (Pressure reducing valve upstream of the bathroom/s.

 

[stevetheplumber]

possibly its the thirty foot of plex acting as a spring when you turn of the preasure expands the plex and the snaps back why not fit a valve before the plex and see if this eliminates the problem or it might just need some more clips

 

[JonLondon]

Thanks for the suggestions so far. Here's an update:

A couple of updates:

I checked the following:

(1) No clamps have been removed from the piping in the basement.
(2) The Pex line appears to be well connected along its route to joists in the basement.
(3) The sound is like a steady groan that lasts five to ten seconds rather than a percussive hammer sound and seems to come from the basement.
(4) The last time I heard the sound -- this morning when an upstairs toilet and sink were used for the first time since last night -- the sound started while the sink water was still running.
(5) As far as the float valve for the cistern, I wonder if it's something else because the groaning sound is coming from the basement, two floors below the bathroom. Also, we never had that sound in 11 years in the house until after the irrigation was installed.

When I add those observations together, I wonder if it's the case that water pressure along the long Pex line to the sprinkler is greater than water pressure through the copper tubing that is used elsewhere in the basement. The Pex line is 1-inch; the copper is 3/4". Is it possible that when water is drawn from the house, water in the Pex line is running backwards to the T-connection to the main copper line and causing it to vibrate?

The walls of the Pex line is thicker than copper, so the interior dimension isn't 1/4" bigger, but it may be somewhat bigger. If that is the problem, how might it be fixed?

 

[REDSAW]

hey jon,

bet a buck its in your bathroom, tap washers/cistern valve for sure.
it sounds like resonation and will transmit this sound all the way to the basement just like a flute, especially if the basement is empty, but knowing you lot it will be where you live in the winter right?.
as the irragation has a check valve it cant be that.

got a mate who lives up the road from you/ london ont' right?. can send him up in the morning if you like eh? small world isn't it buddy.

 

[Blackcatgas]

Try a soix chief (spelling) mini air-ester, its a little valve with a spring loaded piston in it, it is connected to the cold water pipe with a t piece and will damp out the water hammer.
Ive fitted 3 or 4 of these things over the years and they have done the trick.
http://www.siouxchief.com/Resource_/ProductMedia/155/Mini-Rester%20Brochure%202-07.pdf

 

[TGor]

Jon, try disconnecting/isolating the irrigation system and see if the noise is still there ... if it is then the guys are probably right its yer fill valve ... presumably the plumber put in isolating/drain valves not just a solenoid??? get's a bit chill in Canada hey!

 

[bathroomboy]

Jon, have you got an unvented hot water cylinder, if so this noise could be from the expansion vessel deflating after pressure has built up after a period of non use, I had this on a system once and contacted the cylinder manufacturors and they advised mounting the expansion vessel upside down, it has never been a problem since. It may even need repressurising.