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Old 08-12-2019, 06:13 AM   #1
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The Hazards of Backflow /Cross Connections

There are very good reasons your RV may be equipped with backflow prevention devices. The device most discussed and frustrating to RV owners seems to be the vacuum breaker/check valve installed on the black water tank flush system. While sometimes problematic, these backflow preventers are necessary, and it is important to leave them in place if they are working, and replace them if they are leaking or not working as they should. No backflow preventer should ever be eliminated from a system or bypassed — they are there for a good reason, whether you understand their purpose, or not.

In another thread on this forum, I am being challenged to justify the purpose of one of these cross connection devices by somebody who has eliminated it from their black tank flush system. I’ve tried my best to explain the hazards involved with doing this, but this member and some others insist on pushing back and refusing to accept that the possibility of a hazard exists due to this modification. I am being asked to prove how backflow is possible in this situation. I would go blue in the face trying to provide all of the different possible scenarios to this member because he just doesn’t get it. But many people don’t get it.

Here are a couple of videos that might help people to understand the importance of backflow prevention devices and the hazards of cross connections. The first video is short and gives the basics. The second video is long (and old), but it will give people a much better understanding of how these things work and why they are so important.

Bruce

https://youtu.be/l5QoNSPpDZE

https://youtu.be/HLVt6GNxZho
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Old 08-12-2019, 06:40 AM   #2
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Thank you for keeping up the fight for safety. As a recipient of a waterborne illness this is simple way to keep everybody safe.
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Old 08-12-2019, 06:58 AM   #3
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Thanks for the info
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Old 08-12-2019, 07:09 AM   #4
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I second the thanks, and I share your frustration trying to get some people to accept that there should a backflow prevention device in the black tank flush line. It can be as easy as using a garden hose bib backflow preventer on the outside at the flusher port.

EDIT: If you don’t have a flusher installed directly into the black water tank but you use one of those adapters with a back flush nozzle at the dump outlet, you also need to make sure you have a backflow prevention device. They do come with one installed and they shouldn’t be removed.
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Old 08-12-2019, 07:54 AM   #5
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yes, the second 'old school' video is fantastic, and while most of the 'scenarios' and old school fixtures might not seem applicable today, most of us have all of our water lines, and sewer lines, and fixture connections 'behind the scenes', and it's nice to know why these 'air gaps' and 'air admittance valves' and 'loops' and p-traps are important to even today's plumbing... even in RVs.
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Old 08-12-2019, 08:31 AM   #6
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the second 'old school' video is fantastic.
It really is fantastic. If people have the patience to watch the entire video, they will learn a lot and really understand how these “mysterious” devices work and why they are so important.

Not much has really changed with how these things work since then, but nothing has changed with regards to why they are needed and what can happen when they are not used.

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Old 08-12-2019, 03:15 PM   #7
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Bruce - I’ll watch the video but your word is good enough for me. As the wife of a licensed tradesmen (electrician) I have only respect for the education and knowledge you provide.

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Old 08-12-2019, 03:39 PM   #8
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As a 10 year old kid I used to love siphoning water out of buckets. The black tank is a bucket and the hose hooked up to the black water rinse can become a siphon if a back flow device is not in place. Don't argue with common sense, folks.
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Old 08-12-2019, 09:12 PM   #9
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Good information, Bruce.

I understand your frustration. I think some of the resistance comes from peoples' experience with the crappy equipment we see all the time.

It's not only the black-tank flush gear. People see the cheesy backflow preventers they put on the hose bibbs at our campground and others. They leak. They squirt you in the face when you turn the water off (less of a problem for me). And they don't have enough threads to connect a hose leak-free unless you put in an extra washer. At our campground they replace most of the brass hose-bibb backflow preventers annually because they leak out the air vents after being taken out of service for the winter. The dripping water attracts bees. These things lead to dislike/disrespect of all backflow preventers. After all, we didn't need such things as backflow preventers, bicycle helmets, car seat belts and safety seats when we were growing up.

And what, people think, is the risk? Suppose my camper IS on a hill and pressure DOES drop in the campground. My camper's plumbing is clean, and my white USF sanitary hose is clean. Why would anyone care if a gallon of my clean water got back into the system, they think?

Obviously, the black water tank flush is a different situation, and at our campground the hose bibb backflow preventers would block contamination beyond the user's hose.

You have to wonder: Would people be so willing to bypass backflow preventers if they didn't have such a high failure rate?
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Old 08-13-2019, 07:03 AM   #10
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Originally Posted by Larry-NC View Post
You have to wonder: Would people be so willing to bypass backflow preventers if they didn't have such a high failure rate?
Larry,

I always appreciate your perspective and enjoy reading your opinions, especially when it comes to trades-related topics. You have a good understanding of how most things work and you apply logic with first-hand experience to so much of what you have to say. You don’t ask many questions, but you have many answers and opinions that cause me to realize things that I never before would have realized, and your posts often teach me things that I will carry with me forever. I don’t know how you learned as much as you have, but I don’t think it’s just because you stayed at a Holiday Inn Express. All I know is, you’re a smart guy.

Now, to answer your question: I think that most people just don’t understand how some backflow preventers work, they don’t know how to use them, and they often use the wrong type for a particular application. Your example of the backflow preventers used at your campground is a perfect one to support why I think this. I see what you have described all of the time — the wrong type of hose thread backflow preventer has been used for a particular hosebib’s location or purpose. Your campground is apparently using backflow preventers that are either not designed for locations where they can freeze, or they are using the type that are difficult to winterize and stay winterized. I will use the WATTS Series 8 model numbers here for simplicity. The other brands have versions that look almost identical and work the same way. Here is a picture showing all of them:

Well, my connection is too slow to upload the picture, so here is a link to the page: https://www.watts.com/dfsmedia/0533d...ource/es-8-pdf

Of all of these backflow preventers, the only one that is suitable for your campground is the Model NF8. Your campground probably uses the cheaper Model 8A or another one similar to it. The Model NF8 has a simple vacuum breaker (the black plastic collar) that will allow drainage of the hosebib at the hosebib and it also allows the entry of air into the entire system, breaking the vacuum which is holding water in the line downstream of the hosebib to allow drainage from the hosebib back to the point of the system’s drainage without the user having to stand there, pulling the difficult-to-grab stem inside of the hose threads (which they probably don’t even know is there) to achieve the same thing. The Model 8A would work if it was used properly, but they are never used properly. Since the Model 8A isn’t used properly and the undrained water is always left sitting inside of the hosebib and the backflow preventer itself, they freeze, but they usually don’t split, so they give the appearance of still being “good”. This is usually what makes them eventually spray water like you described — the freezing has caused the rubber diaphragm to develop holes and cracks at the brass drainage holes inside of the Model 8A and most of the others beside the Model NF8. So, while the Model 8A is a good backflow preventer, it is not user-friendly, and the correct way to use them is not understood by most people.

This is just one example of why there are so many different types of backflow preventers and why careful thought must go into the decision or regulation for why one version should be used instead of another — they all have a specific purpose, and different conditions/situations will dictate exactly which is the right one to use.

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Old 08-13-2019, 07:52 AM   #11
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Larry,

I failed to mention one additional thing about why the backflow preventer you mentioned might spray water out of it when you turn it off. As they age, the spring that holds the rubber diaphragm down against the drain holes can become weak, or if its not weak, the high pressure in your hose overcomes the force of this spring allowing it to push up when you turn off the hosebib and spray the back pressure water out through the drain holes. You can keep this from happening by turning a faucet on inside of your RV while you are turning off the hosebib.

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Old 08-13-2019, 06:44 PM   #12
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Watts 8B

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Originally Posted by nomad297 View Post
Now, to answer your question: I think that most people just don’t understand how some backflow preventers work, they don’t know how to use them, and they often use the wrong type for a particular application. Your example of the backflow preventers used at your campground is a perfect one to support why I think this. I see what you have described all of the time — the wrong type of hose thread backflow preventer has been used for a particular hosebib’s location or purpose. Your campground is apparently using backflow preventers that are either not designed for locations where they can freeze, or they are using the type that are difficult to winterize and stay winterized. I will use the WATTS Series 8 model numbers here for simplicity. The other brands have versions that look almost identical and work the same way. Here is a picture showing all of them:

Well, my connection is too slow to upload the picture, so here is a link to the page: https://www.watts.com/dfsmedia/0533d...ource/es-8-pdf

Of all of these backflow preventers, the only one that is suitable for your campground is the Model NF8. Your campground probably uses the cheaper Model 8A or another one similar to it. The Model NF8 has a simple vacuum breaker (the black plastic collar) that will allow drainage of the hosebib at the hosebib and it also allows the entry of air into the entire system, breaking the vacuum which is holding water in the line downstream of the hosebib to allow drainage from the hosebib back to the point of the system’s drainage without the user having to stand there, pulling the difficult-to-grab stem inside of the hose threads (which they probably don’t even know is there) to achieve the same thing. The Model 8A would work if it was used properly, but they are never used properly. Since the Model 8A isn’t used properly and the undrained water is always left sitting inside of the hosebib and the backflow preventer itself, they freeze, but they usually don’t split, so they give the appearance of still being “good”. This is usually what makes them eventually spray water like you described — the freezing has caused the rubber diaphragm to develop holes and cracks at the brass drainage holes inside of the Model 8A and most of the others beside the Model NF8. So, while the Model 8A is a good backflow preventer, it is not user-friendly, and the correct way to use them is not understood by most people.

This is just one example of why there are so many different types of backflow preventers and why careful thought must go into the decision or regulation for why one version should be used instead of another — they all have a specific purpose, and different conditions/situations will dictate exactly which is the right one to use.

Bruce
Bruce, you are way too kind. I've learned a little in 74 years and I don't mind sharing.

The campground uses Watts 8B units on the hose bibbs, but never shears off the lock screw. I imagine they've never researched the options, just bought what their supplier offered. We're in the mid-Atlantic. We have a few months of below freezing weather, or at least freezing overnights.

They offer two options:
  1. If you heat your hose all the way to the bibb, you can keep water all year. They leave the backflow preventers in place and cover the water pedestal with a styrofoam barrel. The fulltimers do this.
  2. If you don't heat the hose, they disconnect your hose (if you haven't), remove the backflow preventer (sometime between Halloween and Thanksgiving) and cover the tap with a styrofoam barrel. In April sometime, they remove the barrel and restore the backflow preventer. Many of these drip and must be replaced. Based on your theory, they must have removed them a little too late in the season or restored them too early.
The penalty for messing with the styrofoam barrel in any way is immediate expulsion. This is a serious and costly penalty.

They usually have some water line breaks in the winter due to freezing. I imagine they aren't buried very deep.
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Old 08-13-2019, 06:58 PM   #13
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Getting sprayed

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Originally Posted by nomad297 View Post
Larry,

I failed to mention one additional thing about why the backflow preventer you mentioned might spray water out of it when you turn it off. As they age, the spring that holds the rubber diaphragm down against the drain holes can become weak, or if its not weak, the high pressure in your hose overcomes the force of this spring allowing it to push up when you turn off the hosebib and spray the back pressure water out through the drain holes. You can keep this from happening by turning a faucet on inside of your RV while you are turning off the hosebib.

Bruce
Thanks for the information. I was really thinking of a different situation, residential. All recent homes have hose bibbs with built-in backflow preventers as well as one at the city water meter. I've seen two styles, one with a round cap just behind the bend, and one with a tan handle and the preventer alongside the valve and tap. These spray straight out at you when you do something as simple as turn off a lawn sprinkler that's not holding much pressure. There are kits to repair them, but nobody knows it or they are hard to find, and the big-box stores all want to sell you a new frostproof tap. Then you get involved with making a hole in the wall or ceiling, finding a crimping tool, getting out your sweat-soldering kit, or dumping a few more bucks in a Shark-Bite connector.

It's easy to see why consumers resent this feature that has no apparent value to them. I'm not even sure if every brand can be rebuilt. Do you know?
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Old 08-14-2019, 07:12 AM   #14
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Originally Posted by Larry-NC View Post
Thanks for the information. I was really thinking of a different situation, residential. All recent homes have hose bibbs with built-in backflow preventers as well as one at the city water meter. I've seen two styles, one with a round cap just behind the bend, and one with a tan handle and the preventer alongside the valve and tap. These spray straight out at you when you do something as simple as turn off a lawn sprinkler that's not holding much pressure. There are kits to repair them, but nobody knows it or they are hard to find, and the big-box stores all want to sell you a new frostproof tap. Then you get involved with making a hole in the wall or ceiling, finding a crimping tool, getting out your sweat-soldering kit, or dumping a few more bucks in a Shark-Bite connector.

It's easy to see why consumers resent this feature that has no apparent value to them. I'm not even sure if every brand can be rebuilt. Do you know?
There are so many brands of frost-free hosebibs (wall hydrants) with built-in vacuum breakers on the top of the valve. They can all be rebuilt. There are a few where I can use one brand’s repair kit to repair a different brand — some with a little modification, and some without. They all use the same plunger concept, but there are differences in thread sizes and depths of those threads and the method used to seal the vacuum breaker to the valve. Some use o-rings, some use gaskets and some just use the bottom of the plastic body that holds the plunger to seal when it bottoms-out on the brass valve body. With all of the brands, I have only come across two different sized threads, so I keep the Prier brand kits and the BK/Mueller kits on the truck because of this. I can usually get the job done with what I have. However, there are specific repair kits for every brand/model and sometimes I have to use the specific OEM repair kit, especially with the Woodford brand. Sometimes I need to make a return trip because I don’t have what I need, but that’s no big deal because usually nobody needs to be home since the hosebibs are outside.

The absolute worst enemy of these types of vacuum breakers is backpressure. All of the vacuum breakers are made of thin threaded plastic and they just can’t handle continuous pressure for days on end. The worst-case scenario is when people leave the faucet turned on with a hose and a closed sprayer attached. The sun causes incredible pressure to build in the hose between the sprayer and the vacuum breaker which will cause the vacuum breaker to fail in several different ways, but usually it shears at the top plastic thread of the vacuum breaker body. Another no-no for these types of hosebibs are the timers some people use that require the hosebib to be left turned on. When installed (with slope to outside) properly and used properly, though, these are good frost-free hosebibs. The repair kits for these hosebibs cost me about $4.00.

I think you are talking about the Woodford Model 25 where you mention the type with the backflow preventer to the (left) side of the handle. This is the absolute best residential frost-free hosebib there is — I am in love with these things, but it is also the most expensive to buy and to repair. However, they very rarely need to be repaired because they are designed and built so well and can handle a lot more abuse and misuse by the user. The repair kit for this hosebib costs me about $50.00 when the backflow preventer/vacuum breaker is included. I carry only one of these kits on my truck because I rarely need them.

You don’t miss a thing — those check valves at the water meter you mention are a menace to homeowners in older homes and a money-maker for me. That check valve causes the house’s water system to become a closed system, so if there is not a thermal expansion tank installed in the system, pressure builds in the system as the water heater heats cold water causing the T&P relief valve at the water heater to relieve the pressure once it reaches 150psi. For many years now, the installation of thermal expansion tanks has been a code requirement for all new construction and all water heater replacements, regardless of whether or not the system is closed. This requirement was put in place due to some water companies already having check valves on their system and in anticipation of water companies changing-out their equipment to include a check valve, and due to most PRVs (pressure reducing valves) acting as check valves, I only install PRVs with a built-in thermal bypass, but if there is a check valve at the meter, this doesn’t solve the problems caused to the homeowner of a check valve at the meter. Most of the water meters in the area I work in do not yet have check valves, but the three water companies that service my area are slowly changing-out their old equipment to the meters and the meter yokes that do have them, so if a customer doesn’t already have a (working) thermal expansion tank installed, I explain all of this to them and let them decide if they want me to install one.

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Old 08-14-2019, 07:41 AM   #15
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Bruce, you are way too kind. I've learned a little in 74 years and I don't mind sharing.

The campground uses Watts 8B units on the hose bibbs, but never shears off the lock screw. I imagine they've never researched the options, just bought what their supplier offered. We're in the mid-Atlantic. We have a few months of below freezing weather, or at least freezing overnights.

They offer two options:
  1. If you heat your hose all the way to the bibb, you can keep water all year. They leave the backflow preventers in place and cover the water pedestal with a styrofoam barrel. The fulltimers do this.
  2. If you don't heat the hose, they disconnect your hose (if you haven't), remove the backflow preventer (sometime between Halloween and Thanksgiving) and cover the tap with a styrofoam barrel. In April sometime, they remove the barrel and restore the backflow preventer. Many of these drip and must be replaced. Based on your theory, they must have removed them a little too late in the season or restored them too early.
The penalty for messing with the styrofoam barrel in any way is immediate expulsion. This is a serious and costly penalty.

They usually have some water line breaks in the winter due to freezing. I imagine they aren't buried very deep.
Since your campground leaves the water on throughout the winter and takes the Model 8Bs off, the Model NF8 would really not provide any advantage over how they are doing it now. I suspect that they are failing more due to the constant backpressure on them while they are being used than they are due to freezing. None of the Series 8 backflow preventers are designed for use with extended/constant periods of pressure and backpressure. This is a good example of the wrong type of backflow preventer being used for a specific purpose. There are backflow preventers designed for constant pressure, but they are much more expensive than the Series 8 type backflow preventers. At least your campground is using some form of backflow protection, and replacing them when they fail is definitely less expensive than buying and maintaining the appropriate reduced pressure principle backflow preventer (RPZ) or double check valve that will last longer.

Bruce
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Old 08-14-2019, 10:39 AM   #16
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More on vacuum breakers

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Originally Posted by nomad297 View Post
There are so many brands of frost-free hosebibs (wall hydrants) with built-in vacuum breakers on the top of the valve. They can all be rebuilt. There are a few where I can use one brand’s repair kit to repair a different brand — some with a little modification, and some without. They all use the same plunger concept, but there are differences in thread sizes and depths of those threads and the method used to seal the vacuum breaker to the valve. Some use o-rings, some use gaskets and some just use the bottom of the plastic body that holds the plunger to seal when it bottoms-out on the brass valve body. With all of the brands, I have only come across two different sized threads, so I keep the Prier brand kits and the BK/Mueller kits on the truck because of this. I can usually get the job done with what I have. However, there are specific repair kits for every brand/model and sometimes I have to use the specific OEM repair kit, especially with the Woodford brand. Sometimes I need to make a return trip because I don’t have what I need, but that’s no big deal because usually nobody needs to be home since the hosebibs are outside.
You probably have sources for these items. Our local Lowe's is an "A" store. A stores have the largest area and largest inventory of any in the chain. I can even walk in and get ABS pipe and fittings for trailer repairs to avoid mixing PVC and ABS. But as an experiment I went to the Lowe's website and searched for vacuum breaker repair parts. I found several. Then I checked the filter for "Available for pickup at W. Raleigh Lowe's" and they mostly disappeared. Four items remained:
  • A Delta one-handler repair kit (irrelevant)
  • "American Sillcock Brown Repair Part (maybe a vacuum breaker kit)
  • Woodford Brass Sillcock Valve Replacement Part (This is the entire valve assembly for $19.88)
  • Woodford Brown Brass Replacement Part (The handle and screw for $4.98)
The local homeowner would not be able to easily get repair parts to repair a vacuum breaker. One of the local jobbers here does not want to deal with anyone but plumbers. The other one is actually very helpful, but you have to know where/how to find him.
Quote:
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The absolute worst enemy of these types of vacuum breakers is backpressure. All of the vacuum breakers are made of thin threaded plastic and they just can’t handle continuous pressure for days on end. The worst-case scenario is when people leave the faucet turned on with a hose and a closed sprayer attached. The sun causes incredible pressure to build in the hose between the sprayer and the vacuum breaker which will cause the vacuum breaker to fail in several different ways, but usually it shears at the top plastic thread of the vacuum breaker body. Another no-no for these types of hosebibs are the timers some people use that require the hosebib to be left turned on. When installed (with slope to outside) properly and used properly, though, these are good frost-free hosebibs. The repair kits for these hosebibs cost me about $4.00.
But backpressure situations is how they are being used. Sally Homeowner has always turned the hose nozzle off and left the tap on when watering her garden each day. Joe Carwash leaves his pressure washer connected so he can rinse off his pickup every other day. Sam Golfer is very proud of his putting-green quality lawn. He leaves the tap on and uses a series of timers to water his lawn, even when he's out of town for a week or two. They've always done that and were never told that the new equipment was under-designed and not robust enough to withstand their normal usage pattern. Some people might think that inferior equipment was foisted off upon them by officious code-writers in Washington, DC, who probably live in apartments and condominiums and have never dealt with these issues. They might even relate it to the early ineffective low-flow toilets that were foisted upon them.
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I think you are talking about the Woodford Model 25 where you mention the type with the backflow preventer to the (left) side of the handle. This is the absolute best residential frost-free hosebib there is — I am in love with these things, but it is also the most expensive to buy and to repair. However, they very rarely need to be repaired because they are designed and built so well and can handle a lot more abuse and misuse by the user. The repair kit for this hosebib costs me about $50.00 when the backflow preventer/vacuum breaker is included. I carry only one of these kits on my truck because I rarely need them.
Maybe they rarely fail. A former GF lives in a townhouse where a lot of them failed. I replaced hers (the entire valve)--fortunately there was an access panel so I didn't have to open a wall. The original one had a crimp fitting and was crimped to plastic pipe. I got a longer one (not Woodford, whatever HD had in stock), and a SharkBite connector to keep things simple. No one I asked mentioned that rebuild kits were available. Trade secret?
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Originally Posted by nomad297 View Post
You don’t miss a thing — those check valves at the water meter you mention are a menace to homeowners in older homes and a money-maker for me. That check valve causes the house’s water system to become a closed system, so if there is not a thermal expansion tank installed in the system, pressure builds in the system as the water heater heats cold water causing the T&P relief valve at the water heater to relieve the pressure once it reaches 150psi. For many years now, the installation of thermal expansion tanks has been a code requirement for all new construction and all water heater replacements, regardless of whether or not the system is closed. This requirement was put in place due to some water companies already having check valves on their system and in anticipation of water companies changing-out their equipment to include a check valve, and due to most PRVs (pressure reducing valves) acting as check valves, I only install PRVs with a built-in thermal bypass, but if there is a check valve at the meter, this doesn’t solve the problems caused to the homeowner of a check valve at the meter. Most of the water meters in the area I work in do not yet have check valves, but the three water companies that service my area are slowly changing-out their old equipment to the meters and the meter yokes that do have them, so if a customer doesn’t already have a (working) thermal expansion tank installed, I explain all of this to them and let them decide if they want me to install one.

Bruce
Interesting history here. This area (Sun Belt) has been hot for half a century--really even longer, since air conditioning became widespread in the 50s-60s. Currently population in the county increases by 36,000 per year. (if you assume four people per family, that's 25 new homes per day, seven days a week.

The neighborhood I live in used to be the north edge of the populated area and was called North Raleigh. Now it's been renamed Midtown and North Raleigh is 5 miles further north.

In the 1970s, they realized that the water infrastructure was undersized. They advised everyone to install PRVs and jacked the water pressure to 140 psi. (Most people complied, but there are probably still a few folks who haven't. There are even folks without PRVs that have the old-style washing machine hoses that lack the braided jackets.) Apparently those PRVs (the inexpensive 70 psi ones from Lowe's) do not have integral check valves. There was never a problem with hot water expansion.

Then about 7-8 years ago someone decided it was important that backflow preventers be installed at every meter yoke. A terse note included with the water bill advised adding an expansion tank. I eventually did so. The T&P valve on the water heater wasn't a serious issue, but I had a toilet ballcock that didn't want to stop seeping from the excess pressure.

If your area is just now getting check valves at the meter, this will be a windfall for you. Every time you get called out on a toilet ballcock or "leaking" T&IP, you will get to install an expansion tank and blame the expense on the water supplier.
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Old 08-15-2019, 07:39 AM   #17
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Originally Posted by Larry-NC View Post
You probably have sources for these items. Our local Lowe's is an "A" store. A stores have the largest area and largest inventory of any in the chain. I can even walk in and get ABS pipe and fittings for trailer repairs to avoid mixing PVC and ABS. But as an experiment I went to the Lowe's website and searched for vacuum breaker repair parts. I found several. Then I checked the filter for "Available for pickup at W. Raleigh Lowe's" and they mostly disappeared. Four items remained:
  • A Delta one-handler repair kit (irrelevant)
  • "American Sillcock Brown Repair Part (maybe a vacuum breaker kit)
  • Woodford Brass Sillcock Valve Replacement Part (This is the entire valve assembly for $19.88)
  • Woodford Brown Brass Replacement Part (The handle and screw for $4.98)
The local homeowner would not be able to easily get repair parts to repair a vacuum breaker. One of the local jobbers here does not want to deal with anyone but plumbers. The other one is actually very helpful, but you have to know where/how to find him.

But backpressure situations is how they are being used. Sally Homeowner has always turned the hose nozzle off and left the tap on when watering her garden each day. Joe Carwash leaves his pressure washer connected so he can rinse off his pickup every other day. Sam Golfer is very proud of his putting-green quality lawn. He leaves the tap on and uses a series of timers to water his lawn, even when he's out of town for a week or two. They've always done that and were never told that the new equipment was under-designed and not robust enough to withstand their normal usage pattern. Some people might think that inferior equipment was foisted off upon them by officious code-writers in Washington, DC, who probably live in apartments and condominiums and have never dealt with these issues. They might even relate it to the early ineffective low-flow toilets that were foisted upon them.

Maybe they rarely fail. A former GF lives in a townhouse where a lot of them failed. I replaced hers (the entire valve)--fortunately there was an access panel so I didn't have to open a wall. The original one had a crimp fitting and was crimped to plastic pipe. I got a longer one (not Woodford, whatever HD had in stock), and a SharkBite connector to keep things simple. No one I asked mentioned that rebuild kits were available. Trade secret?

Interesting history here. This area (Sun Belt) has been hot for half a century--really even longer, since air conditioning became widespread in the 50s-60s. Currently population in the county increases by 36,000 per year. (if you assume four people per family, that's 25 new homes per day, seven days a week.

The neighborhood I live in used to be the north edge of the populated area and was called North Raleigh. Now it's been renamed Midtown and North Raleigh is 5 miles further north.

In the 1970s, they realized that the water infrastructure was undersized. They advised everyone to install PRVs and jacked the water pressure to 140 psi. (Most people complied, but there are probably still a few folks who haven't. There are even folks without PRVs that have the old-style washing machine hoses that lack the braided jackets.) Apparently those PRVs (the inexpensive 70 psi ones from Lowe's) do not have integral check valves. There was never a problem with hot water expansion.

Then about 7-8 years ago someone decided it was important that backflow preventers be installed at every meter yoke. A terse note included with the water bill advised adding an expansion tank. I eventually did so. The T&P valve on the water heater wasn't a serious issue, but I had a toilet ballcock that didn't want to stop seeping from the excess pressure.

If your area is just now getting check valves at the meter, this will be a windfall for you. Every time you get called out on a toilet ballcock or "leaking" T&IP, you will get to install an expansion tank and blame the expense on the water supplier.
Larry,

You are right about everything you said. This is why I spend so much time with my customers trying to educate them on this stuff so they can make the decision to change the ways they have always done things or continue to do things the way they have been and then repair stuff when it fails. Quite often I will show customers how easy it is to repair some of these things themselves and I will give/sell them a couple of repair kits for when that time comes. I will, at least, give them the correct part numbers and let them know where they can buy them — usually at Amazon.

I carry the two most-used sizes (2.1 gallon and 4.8 gallon) of thermal expansion tanks on my truck at all times. I install about four per week, but those installations are usually replacements of existing tanks that have gone bad. They seem to last only a couple of years before they become waterlogged or leak at the welds.

Bruce
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Old 08-15-2019, 07:57 AM   #18
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As a non-expert in this area I appreciate your time to educate the forum members who want to learn.

That said and since anyone on the internet can be an expert...it escapes me why Some municipalities would remove the requirement for a plumber to have a license for this very reason.

http://www.fox26houston.com/home/plu...ng-september-1
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Old 08-15-2019, 08:14 AM   #19
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I must be a Reactionary

Quote:
Originally Posted by nomad297 View Post
I carry the two most-used sizes (2.1 gallon and 4.8 gallon) of thermal expansion tanks on my truck at all times. I install about four per week, but those installations are usually replacements of existing tanks that have gone bad. They seem to last only a couple of years before they become waterlogged or leak at the welds.

Bruce
Bruce, This is progress? Taking a plumbing system that only needs maintenance every 7-10 years and installing a meter fitting that then requires the homeowner to install parts that fail this frequently? Forgive my rant, but this is a giant step...backwards.

My expansion tank came from Lowes. It's listed on my MyLowes card, and if it fails I WILL take it back to learn what the warranty is.

One question: Does "waterlogged" mean that the rubber diaphragm fails catastrophically, or that the air just seeps away over time like a bicycle tire? My pressure is 70 psi after the PRV. I filled the tank to 35 psi. If it misbehaves, could I simply depressurize the water system and refill the tank to 35 psi? This is analogous to fixing water hammer by draining the system to get air back in the air hammer arrestors. Doing this every 10 years or so is not arduous. I'll probably do this and see how long it lasts before replacing the tank.
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"Always bypass the water heater before opening the low-point drains."
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Old 08-15-2019, 09:30 AM   #20
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Many years ago I was involved with the backflow thing.

It became law in most areas to install said equipment on new homes and businesses. Few require the majority of homes in the US to install these devices.

So the majority do not have them. They need routine inspections which a licensed plumber must do. $300 a year?

Do all rv’s have backflow devices on the white water system? I do not remember seeing one on my fivers water line. Supposed to be near the connection to the hose. Where do I look?
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