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View Full Version : Antisyphon Valves


Wet_Boots
03-04-2007, 10:58 AM
With the rising cost of brass backflow preventers, is anyone looking at using antisyphon valves instead? Less expense. No valve boxes to dig. No critter-chewed wires. Easy winterizing.

Customers asking "What the &%@#*$!!" are these?!" probably remain the biggest hurdle.

The only real downside to AS valves I've seen are visual, if foundation soil settling twists an installation, and the inevitable need to replace the vacuum-breaker poppet washer somewhere down the line. Also, depending on brand (like Irritrol) the solenoids' ability to endure weathering might be questioned.

londonrain
03-04-2007, 11:42 AM
The water systems in my area require a DCVA regardless. They are also on the lookout for unprotected systems without DCVA's. We installed two DCVA's last week, one was on a meter converted to an irrigation meter. The other DCVA was on an unprotected system with just a gate valve.

sildoc
03-04-2007, 11:56 AM
Never even considered asv's. other than the ease of repair I cant stand the things. No matter how you obscure them in a landscape they always stick out like a sore thumb. Most people are so used to not seeing asv's that when they do it is a homeowner install.

bumper
03-04-2007, 11:57 AM
The vast majority of residential installs in our region are AS valves, not difficult to hide with proper placement and the correct plant material.

I can only remember a faint few service calls where ASV's were not used.

Wet_Boots
03-04-2007, 12:02 PM
Any regional code (like the SBCC) allows lawn sprinklers to be protected by antisyphon valves, which are toxic-rated. Local ordinances might require DCVA's, like many towns in my area did, before the code rewrites made 'toxic-rated' a must. Interesting times, for awhile, when ordinances and codes were contradicting each other. Prevailing codes in my region would allow a locality to raise the bar, and require a PVB or RPZ (both toxic-rated) but they could never mandate a DCVA (not toxic-rated)

Unless I see actual documentation, I will always believe "You must use a DCVA, and not a PVB or RPZ or antisyphon valve" to be a result of local ordinance or (perhaps even more likely) one of those "Because I'm the inspector, and I say so" ~ The logic in using a lower-quality backflow preventer escapes me.

Wet_Boots
03-04-2007, 02:21 PM
This probably isn't a question for users of Double Check Valve Assemblies. Awful hard to trade in buried backflow for anything above ground. More of a PVB versus antisyphon valve comparison.

sildoc
03-04-2007, 03:27 PM
Our community is kind of screwed up. I see alot of pvb's around on the supper old 20+ year systems, You know the ones that used brass sprays and such. but now you are required to use Double checks if you are licensed only and if you are homeowner you can just use asv's with no double check. ??? only those old ones are grandfathered in. Crazy.

PurpHaze
03-04-2007, 04:18 PM
I have ASVs on my house system. I originally put them in 25 years ago and just went manual to start with. Then I converted to automatic about 18 years ago and just kept the ASVs instead of renovating the whole thing. I'm still trying to figure out if I was a DIYer back then. The system still has the original valves and MAs but they don't leak because maybe I was in professional install mode even way back then. :)

Wet_Boots
03-04-2007, 05:08 PM
...but now you are required to use Double checks if you are licensed only and if you are homeowner you can just use asv's with no double check. ??? only those old ones are grandfathered in. Crazy.This is the 'because I said so' aspect I mentioned before. A genuine code requirement for DCVAs would govern all installations. Codes don't care who does the work.

None of the old stuff around here was grandfathered, so all the existing DCVAs became non-compliant the moment the new code was adopted. Sympathy from the government was sadly lacking.

sildoc
03-04-2007, 05:20 PM
I have ASVs on my house system. I originally put them in 25 years ago and just went manual to start with. Then I converted to automatic about 18 years ago and just kept the ASVs instead of renovating the whole thing. I'm still trying to figure out if I was a DIYer back then. The system still has the original valves and MAs but they don't leak because maybe I was in professional install mode even way back then. :)

You probably didn't even realized it was your calling!!!!!:laugh:

Ground Master
03-05-2007, 12:09 PM
an AVB is considered a toxic high hazard device also. Its just not practical in a commercial landscape with a high number of zones.

h20 guy
03-05-2007, 04:03 PM
Ditto on the last response. If you cannot pass on the extra $10 or so, then maybe it's not worth the effort. Better yet maybe just leave the poly pipe above ground [due to increased cost of poly pipe], and give a discount to the homeowner, and just tell them to be extra careful when mowing, also easy for repairs when a leak develops!

Wet_Boots
03-05-2007, 06:04 PM
Ten bucks? Just where the hell do you buy your brass backflow preventers? ;)

Think home systems then, and not large installs with a mainline. California, for instance, will have antisyphon valves on most home systems, and no one really gripes about the look. They got exposed backflow all over the place.

Hereabouts, it was a very hard sell to folks thinking of the all-buried systems with DCVAs. The years have blurred those memories.

My own usage of AS valves is mostly on retrofits of systems with a combination of no/poor backflow and faulty zone valves. Install a bank of AS valves, and you have a compliant functional sprinkler system. Since most installs I see have the pipe exiting a basement (above grade, usually) on the 'utility' side of the house, the valves aren't too much of a disaster, what with gas meters, air conditioners, and electric meters alongside.

For most small home installs, the extra cost of AS valves is balanced by the valve boxes you don't have to buy and install. The savings is the brass BP you don't have to install. I figure that to be about a hundred bucks or so. Even though I normally don't do install quotes with AS valves, I can envision offering them as an economy for some clients just itching to trim some dollars from the cost.

But I don't expect to be offering them on new construction, though. There, I would stick with all copper and brass above ground, with a PVB (or RPZ, if needed) ~ New construction almost always has significant soil settling along the foundations, and AS valves would drop with them. California doesn't have this problem. Copper pipe can be brought an extra foot or so away from the foundation, beyond the settling, and the valves get located in stable soil.

PurpHaze
03-05-2007, 10:06 PM
California doesn't have this problem. Copper pipe can be brought an extra foot or so away from the foundation, beyond the settling, and the valves get located in stable soil.

I thought we were the earthquake capitol of the country??? :)

Wet_Boots
03-06-2007, 09:41 AM
Yeah, come to think of it, after they got over being astonished, the World Series announcers in Candlestick Park back in 1989 (Loma Prieta earthquake) were heard to be saying how tough it was going to be for all the lawn sprinkler systems in the area. :dizzy:

gusbuster
03-06-2007, 04:23 PM
Yeah, come to think of it, after they got over being astonished, the World Series announcers in Candlestick Park back in 1989 (Loma Prieta earthquake) were heard to be saying how tough it was going to be for all the lawn sprinkler systems in the area. :dizzy:

Acutely, it wasn't a big deal (8 min from Candle Stick Park,now 3Com park). I don't recall having too many repairs to the systems my dad, myself and uncle were maintaining.

I did have a repair in Foster City where water from the swimming pool washed away the support(cement pad) for the flow protector, but that was the only thing that came to mind.

Regarding piping, most of repairs had to do with stuff falling on irrigation components rather than the earthquake itself.

Getting back to asv valves, part of the issue has to do with space for the yard. You are going to see asv somewhere in a back yard than the front yard, though, now with the newer houses you're going to find in the Valley and stuff, the only underground stuff is on the commercial jobs.

I do see way too many asv installed by so called contractors and dyi's installed at ground level and in boxes. I have lost bids because the people wanted the asv valves underground. I won't because I always explain that it isn't to code.

Wet_Boots
03-06-2007, 04:50 PM
Below-grade vacuum breakers always astonish me. I know there's a point where too many zones make AS valves hard to go with. Also, with heads on tall risers, or a bit of upslope from a house, one could hide a single tall PVB behind a chimney, where a row AS valves would be hard to look at.

Once or twice, I've used them mainly to preserve system pressure in neighborhoods that had very low static pressures. I don't expect to be doing any more systems where I ran lots of copper in the basement, in order to exit on the utility side of a house, with a grouping of AS valves.