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jabeles

Active Member

Posts: 11

Location: USA

1

Thursday, October 6th 2005, 7:38am

Richdel valve

Hi!

My sprinkler system is leaking from (what I assume is) the backflow valve where the pipe emerges from the foundation about a foot off the ground. [:I]

I removed the two-inch (or so) diameter hex cap which is green and says "Richdel 3/4" valve 150 psi max 110ºF H2O max 'R705' Carson City, Nevada" on it. The cap has a kind of bonnet on it through which water can escape when it's closed (see below).

This cap has a small white plunger inside which I gather is some kind of shut off device which operates to close the valve when there is pressure in the system but enable the system to drain when it turns off.

This cap is cracked and the O-ring needs replacement.

QUESTION: I can't find *any* Richdel parts on the Web. Seems Richdel is old news, acquired or went out of business. So I found something from Basic Irrigation Parts (http://www.basicirrigation.com) that I ordered, as follows:

711 Series 3/4" Cap & Float (BPHR-7)

sooooo.... my question is: Will this match the threads and will it work in my system???

If not, any suggestions as to how to replace this part? Or another course of action (replacing the entire valve?)?

Help! [:p]
Joe

Wet_Boots

Supreme Member

Posts: 4,045

Location: Metro NYC

2

Thursday, October 6th 2005, 4:52pm

Your problems go far beyond Richdel. If your system has more than one zone, and you only have one of these Richdel devices, then you actually have no backflow protection at all, and never did.

If this device you describe is located between the shut-off valve of the sprinkler system, and the electric zone valves, and is also at an elevation that is a foot-and-a-half higher than any sprinkler head or pipe that feeds from it, then you can replace it with a Pressure Vacuum Breaker. Then you will have genuine backflow protection.

Money is the reason the job wasn't done right in the first place. A PVB is a hundred-dollar brass assembly.

By the way, if the elevations of the sprinkler heads are higher than the old Richdel device, you will need to either elevate the new PVB, or step up to an even-more-expensive device known as a Reduced Pressure Zone backflow preventor (RPZ for short)

jabeles

Active Member

Posts: 11

Location: USA

3

Friday, October 7th 2005, 10:24am

Responding to your comment, Wet Boots,

I would doubt the previous homeowner would have skimped, but I have little doubt that his installer might have cut corners and put a few $$$ away thereby for his son or daughter's college savings. [:(]

Actually this device is at least 1.5 feet higher than any emitter, so the PVB should work. Is this an "anti-siphon valve" and if not what's the difference? I'm assuming that the issue with backflow is that water in the sprinkler system can enter the home under unusual conditions. Correct?

I'm willing to replace this assembly as you suggest, but I guess I'm looking for some confirmation that what I have is not adequate. Still wondering ... what is that gizmo? And why can't I find replacement parts to get the system working temporarily.

See, I'm putting in a new seeded lawn and really need this system to be operational. Can't wait on putting in the new lawn because the outdoor temperatures are only going to hold so long.

Appreciate [:)] any help.

Joe
Joe

Wet_Boots

Supreme Member

Posts: 4,045

Location: Metro NYC

4

Friday, October 7th 2005, 1:16pm

You could visit a library and check the National Standard Plumbing Code, and what it requires for sprinkler systems. Despite the name, the NSPC is regional, not national, but most of the regional codes are very similar. The function of a PVB is like that of your device, which is an atmospheric vacuum breaker, or AVB - when you combine an AVB with a shutoff valve, either electric or manual, the resulting combination is the antisyphon valve you speak of.

Where the PVB differs, is that it is designed and approved for continuous 24/7 water pressure. It also has small test valves on it, so a special gauge can be attached for confirming the function of the check valve that is part of the device. The AVB is intended only for temporary water pressure, and it can never have any type of shutoff valve downstream of it, on the grounds that the AVB would stay under pressure, stick shut, and become useless.

Where the AVB sees code-approved use, is in it's antisyphon valve form, with one antisyphon valve for each zone of the system, with the same elevation difference that is essential for the protection. With nothing in between the AVB and the sprinkler heads, the AVB won't be under continuous pressure. Both the AVB and PVB are gravity devices, protecting your water supply, because water will not run uphill in a pipe with an opening to the atmosphere. It is the PVB only, though, that makes that opening to the atmosphere a sure thing.

jabeles

Active Member

Posts: 11

Location: USA

5

Saturday, October 8th 2005, 10:39am

Wetboots,

Thanks for your reply. You clued me in to the correct nomenclature of AVB and PVB. A quick web search revealed helpful information I was not able to find without that nomenclature.

I received the Irritrol part and was able to install it. {711 Series 3/4" Cap & Float (BPHR-7) }

As a result, my irrigation system now functions as historically it did, but (as you ably point out) using an AVB upstream of the solenoid valves causes this AVB to remains under pressure and will not protect the house potable water system from a sudden drop in pressure that could occur if, e.g., a sudden demand for water in the house from multiple sources were to cause backflow from the system with the solenoid valves turned off.

But to get backflow to the potable system one would need contaminated water upstream of the solenoid valves.

The chances of this happening seem awfully slight: One would have to invoke backflow into the sprinkler piping all the way from the emitters upstream past the solenoid valves under pressure sufficient to keep the AVB closed -- which is hard to imagine after the solenoid valves close. Even if pressure were to be lost entirely in the house water system it is still hard to believe that hazardous water could be brought back into the house from from far downstream of the solenoid valves if they are below the solenoid valve height.

This irrigation system was most likely installed about 20 years ago. I wonder what the state of the art (the plumbing code) was at that time? I suspect the AVB might have been intended not to prevent backflow per se but to facilitate winterization of the irrigations system. Simply opening each solenoid valve with the main valve closed would have tended to drain the lines a bit, perhaps sufficient to prevent damage in freezing conditions. Or, the lines could have been blown out from the AVB.

Your thoughts very much appreciated. I am looking into, nevertheless, replacing the AVB with a PVB considering the code issues, and am wondering, inter alia, why the home inspector did not note this deficiency when we purchased the house several years ago.

Joe
Joe

Wet_Boots

Supreme Member

Posts: 4,045

Location: Metro NYC

6

Saturday, October 8th 2005, 1:43pm

Home inspectors today still don't catch bad sprinkler plumbing. The next time someone dies from bad lawn sprinkler plumbing, you can count on that changing. When it happens, it will be a chain of circumstances that will seem to be incredible. But it will be a chain that would have been broken by the proper backflow prevention.

In case you didn't know it, the solenoid valves that shut off the flow of water to the sprinklers are completely incapable of preventing that same water from flowing backwards through them, should there be a drop in water pressure. And water pressure does drop. It sometimes disappears. Sometimes it even goes negative, when a fire truck hooks up to a hydrant.

Twenty years ago, the codes were largely the same. What has changed between then and today is the evaluating of the risk. Some of the language describing the risk has changed. You describe the odds of backflow occurring as "awfully slight." However slight you may think it to be, it does occur. There is even one backflow death on the records, from more than a generation back.

Back then, a lawn sprinkler system was described as "low hazard" as opposed to "high hazard" and "lethal" ~ but nowadays the phrasing has changed to "non-toxic" and "toxic" (I think we still have "lethal")

Since the possibilities of lawn sprinkler backflow include substances you'd never stir into your coffee, however awfully slight the possibilities could be (fertilizers, pesticides, and the occasional dead rabid animal in the puddle of water around that one low sprinkler head) the level of risk for a lawn sprinkler system is "toxic" and the proper backflow will have an opening to the atmosphere.

The reason you will upgrade the plumbing to code is that your home is technically unsaleable as it presently is. Also, even if you sell your currently-defective home, the responsibility for it being up to code can follow you later. You can probably find some case law on this.

jabeles

Active Member

Posts: 11

Location: USA

7

Saturday, October 8th 2005, 5:36pm

Hi "Wetboots"

This does seem to have turned into the proverbial can of worms.

As for the solenoid not providing any protection against backflow, I do believe that depends on their being some signficant positive pressure and water supply (both factors) in the irrigation lines in excess of that in the potable water system. I mean, I don't think the solenoid is a wide open sluice gate for backflow. However I suspect you are correct that they are designed to hold off a head of pressure coming from the supply line, not (certainly not) the other way around.

Certainly, it would benefit us to keep a close eye in the near future on any use of the fire hydrants (one's right in front of the house) that leads to significant depressurization of our potable water system. The township does drain these annually, but I never paid attention to this before... nor have I seen any dead animal carcasses.

I don't know whether the home *practically speaking* is unsaleable since we bought it in that condition with the help of an apparently assiduous and honorable -- certainly hardworking -- inspector. [:(] Perhaps the right statement rather is that it should be unsaleable without a PVB valve but this might or might not be caught by the next buyer's inspector should we ever sell the place.

You are correct, however, on the issue that it is something that must be dealt with. What I'm left to wonder is whether the sprinkler system was properly permitted originally. That is a potentially significant issue. Since a major renovation was performed at that time and many many drawings were filed with the local government, it's hard to believe that it wasn't inspected then. BTW there is an older irrigation timer located next to the electrical panel (also Richdel as is the currently functioning timer) which has been disconnected but not removed. Hard to say what that signifies other than that there has been a long-term use of a sprinkler system dating back more than a few years before we bought the house -- i.e., odds certainly are that it was here at the time of the major renovation. Furthermore there are lines going underneath the driveway and that has (from its condition) not been replaced for many years.

But if not, there are other issues to be concerned with here. You might or might not be aware that permits and inspections are critical to satisfying the homeowner's responsibilities for insurance coverage -- this is not a trifling matter, not at all.

Interestingly, the AVB is all-plastic construction; I guess a PVB also be all-plastic. E.g., the Toro model 53300 (a PVB shown at their website) does appear plastic. This could make a significant difference in whether I am replacing like for like (and therefore do not need a permit) or am installing something new.
Joe

Wet_Boots

Supreme Member

Posts: 4,045

Location: Metro NYC

8

Sunday, October 9th 2005, 1:54am

Don't waste time and money on a Toro plastic PVB. Get a brass one.

<blockquote id="quote"><font size="1" face="Verdana, Arial, Helvetica" id="quote">quote:<hr height="1" noshade id="quote">Certainly, it would benefit us to keep a close eye in the near future on any use of the fire hydrants<hr height="1" noshade id="quote"></blockquote id="quote"></font id="quote">No, you won't keep a close eye on hydrants. Or anything, for that matter. Codes are in place so that the proper construction practices removes any obligation to keep an eye on things. When a water supply is compromised, it's by something out of the blue that no one could have kept an eye on. I've clipped an occasional news story about backflow events. They keep happening.

As for protection, permits and inspections are worth the paper they are written on. You could get written acceptance of defective plumbing by any and all authorities, and find that it's worthless if someone is harmed by it. Some fellow in New Hampshire who sold his house found himself tried and convicted of negligent homicide, when a faulty damper on an auxilliary heating system allowed a fatal buildup of carbon monoxide. How the prosecution established his prior knowledge of the faulty damper, I don't know, but the verdict indicates that they did.

You now have prior (to the future sale of your home) knowledge of the missing backflow prevention in your sprinkler system, and Google will have a public record of it for many years to come. The money to fix the fault (around a hundred for the materials) is a better investment than spending time wondering about past practices or paperwork.

Think of backflow prevention like emergency brakes for your plumbing. You may go through an entire lifetime and never have to stop your car with the emergency brakes. But if you ever had to, you'd want them in good working order.

jabeles

Active Member

Posts: 11

Location: USA

9

Sunday, October 9th 2005, 7:32am

I'm doing a little prospecting on the WWW to find support for your strong statements about backflow.

from http://www.treeo.ufl.edu/backflow/casehist.asp#25

25. - BACKFLOW AT A PREMISES
WHERE THE CONSUMER'S POTABLE WATER SYSTEM
SUPPLIES AN IRRIGATION PIPING SYSTEM

DATE OF BACKFLOW INCIDENT: October 1991 LOCATION OF BACKFLOW INCIDENT: Southgate, Michigan SOURCE(S) OF INFORMATION: - Drinking Water & Backflow Prevention, Volume 9 Number 6 (June 1992)
- Pacific Northwest Section of the American Water Works Association, Summary of Backflow Incidents, Fourth Edition, 1995
- Watts Industries, Inc.; Watts Regulator News/Stop Backflow

CASE HISTORY

On October 1, 1991, two homeowners in the City of Southgate, Michigan, found parasitic worms, or nematodes, in their water. One homeowner found the worms swimming around in his bathtub when he started filling the tub for his child. He also found rust and other debris in his water. The Wayne County Health Department determined that water had backflowed through a residential irrigation system into the public water system.

An atmospheric vacuum breaker on the residential irrigation system had malfunctioned because the device's air inlet valve had stuck to the device's air inlet port. There was a water main break, which caused a vacuum in the public water system. The vacuum in the public water system sucked some water--and some nematodes--from the irrigation system into the public water system.

Crews from the City's Department of Public Services opened fire hydrants and flushed all the water mains located three blocks north and south of where the backflow incident occurred. Analysis of subsequent water samples collected by the Department of Public Services showed no detectable coliform bacteria.

The County cited the owner of the irrigation system for improper installation of the system. The contractor that this resident employed to install the irrigation system did not have a City permit and used a "cheap" atmospheric vacuum breaker.
Joe

jabeles

Active Member

Posts: 11

Location: USA

10

Sunday, October 9th 2005, 7:40am

More on backflow resources on the web:

1. The American Backflow Prevention Organization http://www.abpa.org/

2. CASE HISTORIES OF SELECTED BACKFLOW INCIDENTS FLORIDA DEPARTMENT OF ENVIRONMENTAL PROTECTION http://www.mindspring.com/~loben/casehist.htm
http://www.treeo.ufl.edu/backflow/casehist.asp#25

3. Backflow Prevention Techzone http://www.backflowpreventiontechzone.com/

What is very hard to find, however, is specific information on the problems associated with backflow. Clearly, the one case study I've seen already relates to the problems occurring after a loss of water main pressure.

However, I have to agree that the issues relating to backflow are inadequately understood. Essentially there is a cross connection problem whenever the sprinkler system is open by a valve to the solenoids.
Joe

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