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Summett
05-29-2008, 11:37 PM
Here's my situation...

Newly constructed home [entirely finished] with a dedicated line that was installed for a future irrigation system. Well, the future has arrived, and had an irrigation specialist over for a bid. He ran some gpm tests, and upon checking the water pressure with the test being run, he shuts off the line valve and we get an Extreme water hammer [only when it was shut off abruptly]. if he slowly shut the valve...no hammer.

His opinion that was there was a problem with the dedicated supply line (which was the new 1" plastic line) and that it wasn't large enough to handle the 18 gpm flow that he said was running thru the line. And, he had a concern that he said at that rate, the valves would probably close quickly causing the hammer.

So, had the plummer over today and only real suggestion that he could give was that he didn't think the irrigation valves would close that quick to create the hammer, but if they did, that he would install an arrestor.

My fear is having an irrigation system installed, along with an arrestor, and the water hammer continues...then what??? My house is completely finished, so an increased 1 1/4" line option is probably not viable.

What options do i have?

I realized that many of you experts may need more info to help me out, so ask away.

thanks much in advance for all the advise.

[signed]
"A guy who REALLY wants an irrigation system."

DanaMac
05-30-2008, 12:03 AM
More than likely you'll be fine with no hammer. Make sue to NOT use the Rainbird DV series valves. They close very abruptly and may cause hammer. Go with either Irritrol, Hunter, or WeatherMatic valves. I've also found that valves with flow controls, even if they are not adjusted, tend to close slower.

Good luck!

No Rush
05-30-2008, 12:13 AM
what size is your water meter? what is your static pressure? what type of 1" pvc do you have (sch 40, class 200)? also, you could get another opinion from another irrigator in your area.

Summett
05-30-2008, 12:13 AM
Thanks DM...that's encouraging. I believe he'll use Hunter valves (as that's the heads he's using) but i'd have to double-check.

It was just a WICKED hammer. I mean, even the plummer looked at his other plumber when i showed it to him and he said..."have you ever heard a hammer like that?" It wasn't something that i really cared to hear. :dizzy:

Summett
05-30-2008, 12:19 AM
what size is your water meter? what is your static pressure? what type of 1" pvc do you have (sch 40, class 200)? also, you could get another opinion from another irrigator in your area.

It's on a well w/ 1hp pump. Not sure if i follow you on static pressure, need a little help on that question. Pipe is a ViegaPEX Ultra 1" SDR-9. Doesn't list a "class #" on it.

lowvolumejeff
05-30-2008, 05:27 AM
I bet the solution is based ion the velocity thru the 1" plex when running such a high GPM. I went to the PEX makers site, and the download shows the velocity is too high. www.viega-na.com/downloads/1201798836TD-PFVPU%200307%20ViegaPEX%20Ultra.pdf
Might want to limit your zones to less tahn 16 GPM (Velocity = 8 FPS) or better yet, 14 GPM to be safe.

Jeff

AI Inc
05-30-2008, 07:03 AM
More than likely you'll be fine with no hammer. Make sue to NOT use the Rainbird DV series valves. They close very abruptly and may cause hammer. Go with either Irritrol, Hunter, or WeatherMatic valves. I've also found that valves with flow controls, even if they are not adjusted, tend to close slower.

Good luck!

Hunters will close a lot faster then a RB dv. RB,s take about 30 seconds , Hunter is almost immidiate.

Putting check valves in all the heads will also help to control it ,as the zones will not be empty thereby slowing water speed when a zone turns on.

No Rush
05-30-2008, 07:22 AM
to get a Static pressure reading; you will need a gauge to take a reading on a hose bib or as close to the water source as possible. Read this:

http://www.irrigationtutorials.com/waterhammer.htm

FIMCO-MEISTER
05-30-2008, 08:37 AM
Hunters will close a lot faster then a RB dv. RB,s take about 30 seconds , Hunter is almost immidiate.

Putting check valves in all the heads will also help to control it ,as the zones will not be empty thereby slowing water speed when a zone turns on.

Ditto... I'd stay away from the Hunter valve line. The SRV is junk in my opinion.

AI Inc
05-30-2008, 08:50 AM
They stopped making the srv. To answer my own question from last week, no other hunter valve will screw to a srv body.

Wet_Boots
05-30-2008, 09:03 AM
How long a run of tubing is involved here? The longer the run, the greater the hammer. You may have to bring your flows way down to around 10 gpm or less.

DanaMac
05-30-2008, 09:05 AM
Hunters will close a lot faster then a RB dv. RB,s take about 30 seconds , Hunter is almost immidiate.

Putting check valves in all the heads will also help to control it ,as the zones will not be empty thereby slowing water speed when a zone turns on.

I don't know where you get your DVs from, but it's just the opposite here. DVs are immediate and cause lots of abrupt water hammer. I had one meter burst apart due to it. Hunter close slow.

Kiril
05-30-2008, 09:06 AM
More zones, better valves

No Rush
05-30-2008, 09:29 AM
larger valves and larger laterals; increase main line to 1 1/4" / 1 1/2", that should work.

Wet_Boots
05-30-2008, 09:32 AM
Instead of guessing, plumb a zone valve to this POC and test it.

DanaMac
05-30-2008, 09:37 AM
Instead of guessing, plumb a zone valve to this POC and test it.

False reading though don't ya think? Less fittings, ells, PVB/RP, no resistance, completely open/full flow.

Wet_Boots
05-30-2008, 09:47 AM
False reading though don't ya think? Less fittings, ells, PVB/RP, no resistance, completely open/full flow.So throttle down the shutoff valve used for connecting to the POC and restrict the outlet if you want.

Hey, Toro valves close pretty slow :)

DanaMac
05-30-2008, 09:54 AM
So throttle down the shutoff valve used for connecting to the POC and restrict the outlet if you want.

Still not going to be accurate. I think he'd be fine if they did not build the zones at a high flow rate. Maybe use standard 3/4" GPM design. 10-12, maybe even go to 14 GPM.

Honestly, I can get a bad hammer noise on almost any system if I shut down a ball valve immediately while a zone is running. High pressure, low pressure, high/low GPM, 3/4"/1". Doesn't matter.

Hey, Toro valves close pretty slow :)

Yeah, they may never close at all!! :laugh:

Wet_Boots
05-30-2008, 09:58 AM
Until the length of the line is known, it's all guesswork.

Summett
05-30-2008, 10:19 AM
Wow...woke up to a lot of assistance. Thanks much.

The line is rather long...about 50'. I looked at the estimate, and the valves listed are DV 100's (??), but it's a little tough to read his writing.

The increased line suggestion was what my irrigation guy had also told me, however with a finished basement (and the line running through the floor) i don't see how that's possible without pulling up the floor or tearing down the ceiling. Don't think the wife would be jazzed about that!

I'm hoping to have the plumber and the irrigation guy get together and discuss the issue. Too bad it wasn't done when the house was being built, but that wouldn't have been to easy.

Kiril
05-30-2008, 10:22 AM
If the system is in place already, do yourself a flavor (and save some money) and plumb in a slow closing master valve so you can sleep at night. You might need to get a different controller that will allow you to manipulate the master valve in a fashion that will prevent the water hammer.

Wet_Boots
05-30-2008, 10:24 AM
Rethink the DV valves, even if it means getting another irrigation guy. The original Richdel valve design closed slowly enough, and can still be had as the Irritrol 205F ~ but also rethink the flow, even if it means more zones.

Summett
05-30-2008, 10:48 AM
Thanks guys. Actually no, the system isn't in yet, so will pass along your suggestions. My irrigation guy handles both RB & Hunter, so he should have some options with the types of valves he uses...as well as maybe working with the flow rates.

At this point he's estimated 57 heads on 10 zones, so maybe that will have to be adjusted.

thanks again for all your input. :drinkup:

Wet_Boots
05-30-2008, 10:54 AM
You can always use smaller nozzles in most of the heads, even without rezoning a system.

Kiril
05-30-2008, 11:04 AM
You can always use smaller nozzles in most of the heads, even without rezoning a system.

Ditto....MPRotators to the rescue

WalkGood
05-30-2008, 12:17 PM
Thanks guys.


I am curious..... does anything else in the house cause water hammer like maybe a dishwasher, washermachine, toilets?

Summett
05-30-2008, 12:20 PM
I am curious..... does anything else in the house cause water hammer like maybe a dishwasher, washermachine, toilets?

Actually no, not at all. That Viega piping was used throughout (obviously smaller size), but the only one that hammers is the 1" irrigation line. And like stated before, only when you abruptly close the inline ball valve.

WalkGood
05-30-2008, 12:47 PM
Is there a pressure reducing valve feeding the house side of the connection? That and smaller inside piping can reduce water hammer on interior fixtures.

Also be sure to firmly secure the larger piping for the irrigation. Wobbly pipes bang against structures making the hammer sound much worse.

Summett
05-30-2008, 12:58 PM
Is there a pressure reducing valve feeding the house side of the connection? That and smaller inside piping can reduce water hammer on interior fixtures.

Also be sure to firmly secure the larger piping for the irrigation. Wobbly pipes bang against structures making the hammer sound much worse.

I don't believe there is a pressure reducing valve feeding the house. Basically it's a 1" copper coming out of the pressure tank and connects directly to 1" supply line, as well as t's to the 3/4' house line (and i don't see any reducing valve there).

I will double check how secure the line is, but once it gets beyond the mechanical room (in the floor) i won't be able to adjust it at all since it's finished. But i'll look.

Mike Leary
05-30-2008, 03:46 PM
I had that problem on a existing system, the plumbers installed what is called a
"hammer arrestor", worked fine, it absorbed the shock.

Mike Leary
05-30-2008, 05:08 PM
I had that problem on a existing system, the plumbers installed what is called a
"hammer arrestor", worked fine, it absorbed the shock.
Or, it was called a "shock arrester", check with plumbing supply house.

Summett
05-30-2008, 05:20 PM
Or, it was called a "shock arrester", check with plumbing supply house.

Thanks Mike. I actually have been asking around about it, and impression i get from speaking with a few plumbers is most say "it should work".

I've been pondering another option that i "may" have, but won't know exactly until i go home and look at our home plans.

Our mechanical room sits along the front of our house, and it may be be a possibility of plumbing out a new line (1 1/2" copper) out the front of the house. And, it may just be in a corner space right next to our front porch, so with a nice bush installed, may not be visible.

Only concern is that i have a brick faced front, so i'd have to have a hole drilled through that. But, that may be the best option of all.

Mike Leary
05-30-2008, 05:38 PM
In that case, be thinking about how to winterize, I understand it gets a tad chilly up there.
Oops, the forum boys are going to kill me; the first mention of winterize. :dizzy:

Summett
05-30-2008, 06:11 PM
In that case, be thinking about how to winterize, I understand it gets a tad chilly up there.
Oops, the forum boys are going to kill me; the first mention of winterize. :dizzy:

I wouldn't think it would be any different than winterizing the other line (with a drain valve on the inside of house), but i'll ask it there would be anything specific with winterizing going thru that brick face.

AI Inc
05-30-2008, 06:13 PM
I wouldn't think it would be any different than winterizing the other line (with a drain valve on the inside of house), but i'll ask it there would be anything specific with winterizing going thru that brick face.

Screw the inside. Put a boiler drain on the outside where it belongs. Keep things simple.

Mike Leary
05-30-2008, 06:37 PM
Boiler drain on the inside, insulated enclosure on the outside, quick-couple for air
compressor winterize irrigation.

Waterit
05-30-2008, 11:39 PM
Thankfully winterizing down here means draining the pump and turning off the breaker!

Startups can be fun - electric motor sits unused for 3-4 months in corrosive salty air, binds up, sorry Mr. Customer, you need a new one.

We advise all of our clients to go to a 2x per week schedule from Nov - Feb, then go to every other day. Some listen, some don't and do total shut down and get new pumps every spring!

FIMCO-MEISTER
05-31-2008, 07:27 AM
In a search RB recommends the PGA valve for slow closing and avoiding water hammers.

Wet_Boots
05-31-2008, 07:32 AM
RB also recommends Maxipaws....

FIMCO-MEISTER
05-31-2008, 07:35 AM
RB also recommends Maxipaws....

Your Point?

Wet_Boots
05-31-2008, 07:37 AM
Your Point?Rainbird is a pack of misguided scoundrels?

FIMCO-MEISTER
05-31-2008, 07:46 AM
Rainbird is a pack of misguided scoundrels?

Which makes them different from whom?

Wet_Boots
05-31-2008, 07:59 AM
Which makes them different from whom?....different from the Godly Company, which is just incompetent :p

FIMCO-MEISTER
05-31-2008, 08:01 AM
....different from the Godly Company, which is just incompetent :p

I'd respond but IT"S PANCAKE TIME!:dancing: