Chemical backflow possibility through Hydrominder

[bigjws]

Does anyone know if the venturi effect created by the educator of the Hydrominder would work in reverse? Say if the hydrominder was stuck open, and there was suction on the line instead of pressure coming in, would it still suck the chemical back into the city water or is the educator designed to only go one way? The city is trying to force me into installing some $2k backflow preventor on my incoming main. I'm technically 'air gapped' everywhere except for the incoming chemical into the hydrominders.

 

[GoBuckeyes]

While I believe the Hydrominder Siphon Breaker and/or E-gap Eductors are to prevent your solution tank from continuing to draw chemical I would think they might also do the same if your incoming water line had negative pressure. You could always drill a hole in the hydrominder discharge tube which would allow air to be sucked into the main water line rather than solution or chemical concentrate. I would call Hydro at (513) 271-8800 and ask them for supporting documents if you're going to be trying to argue with the city.

 

[Eric H]

It could happen but there would need to be multiple failures for it to happen. You could call Dema and ask them for some documentation that says it can't happen.
To the best of my knowledge a backflow preventer on the incoming water lines is required by code. If your plumbing inspector is telling you that you need one just ask him for the code so that you can make sure that you meet all of the requirements. If you don't agree with the code or his interpretation you can then discuss it after you've read the code. In the end, if he says you need it he won't sign off until it is installed.
"You can't fight city hall" - Mr Brady

 

[MEP001]

The city isn't concerned about just the Hydrominders. They want the whole building protected from any chance of contaminating the city supply.

Why is the backflow preventer $2,000? Is that including installation? My 2" incoming RPZ backflow valve was damaged in the freeze, and even now it's only $600 replacement cost.

 

[Randy]

A Backflow preventer RPV is required by most municipalities. I’m kind of surprised that you’ve gotten by this long. How old is your car wash? The water purveyor will designate which backflow preventer can be used, they’ll have a list of which RPV’s that can be used, and some are more expensive than others. In our area it was OK to install the RPV in the equipment room. Now the law has changed, for new installs and rehab’s you have to install the RPV outside in a heated hot box so $2000 is a pretty cheap install if that is what you have to do. When I was state certified to test RPV’s the unit I liked the best was the Zurn Wilkins 975XL, they are about the simplest to work on. Once you have it installed you’re going to have to have it inspected and tested yearly unless the water purveyor forget to send you an inspection notice.

 

[Rodebaugh1]

A Backflow preventer RPV is required by most municipalities. I’m kind of surprised that you’ve gotten by this long. How old is your car wash? The water purveyor will designate which backflow preventer can be used, they’ll have a list of which RPV’s that can be used, and some are more expensive than others. In our area it was OK to install the RPV in the equipment room. Now the law has changed, for new installs and rehab’s you have to install the RPV outside in a heated hot box so $2000 is a pretty cheap install if that is what you have to do. When I was state certified to test RPV’s the unit I liked the best was the Zurn Wilkins 975XL, they are about the simplest to work on. Once you have it installed you’re going to have to have it inspected and tested yearly unless the water purveyor forget to send you an inspection notice.

They never forget

 

[Rodebaugh1]

The city isn't concerned about just the Hydrominders. They want the whole building protected from any chance of contaminating the city supply.

Why is the backflow preventer $2,000? Is that including installation? My 2" incoming RPZ backflow valve was damaged in the freeze, and even now it's only $600 replacement cost.

My last one was also about $600 2 years ago. They are now a little over $800. Mine is brass. If you move up to bronze, they get much higher priced.

 

[cantbreak80]

They never forget

And, be prepared to have your Sewer District inspect/test your sand/oil separator every year, too.
BTW, it won't be free!

 

[Toms PTcarwash]

Very surprised you didn't have to install a backflow preventer sooner. In most areas, they are required on even residential water supplies.
I have a 2" water main and 2" backflow preventer. I am required to provide testing for the preventer every 5 years.
If you do not have a preventer and add one, you will most likely have to add an expansion tank(s) to your water heating, as you will no longer be able to expand back into the municipal system.

 

[Toms PTcarwash]

When you buy a backflow preventer, make sure you get one that will flow your required GPM. They are not all created equal. You can probably get a POS one for $600 or 700 that may last a few years before puking on the floor, but a good Watts 2" is about $2k.

 

[Toms PTcarwash]

And, be prepared to have your Sewer District inspect/test your sand/oil separator every year, too.
BTW, it won't be free!

Yes, just another fun time. In my area, they have "annual Inspections". It is a $50 charge on top of your regular sewer bill. I had several years when they did "semi annual" inspections and tried to charge me both times. You need to be aware of the codes and don't be afraid to speak up.

 

[MEP001]

You can probably get a POS one for $600 or 700 that may last a few years before puking on the floor, but a good Watts 2" is about $2k.

Mine is not a POS. It's a "good Watts 2" that was $600 new. It was 20 years old before the freeze damaged it.

 

[Earl Weiss]

At 3 of my Tunnel I have a "Break Tank" instead of Back Flow preventer. At the other there is the RPV valve. No annual inspection needed for the Break Tank system.

 

[bigjws]

The city isn't concerned about just the Hydrominders. They want the whole building protected from any chance of contaminating the city supply.

Why is the backflow preventer $2,000? Is that including installation? My 2" incoming RPZ backflow valve was damaged in the freeze, and even now it's only $600 replacement cost.

What was the model you got for $600?

Yes, $2k was a ballpark figure because they wanted it buried out by the meter. I've since 'convinced' them that if I'm going to do this at all without a huge fight, it's going to be installed in the room, and they've agreed to that.

The wash has been here since 1982, and nothing was required at that time (we added automatics at a different location in a new building in 1998 and had to have an RPV installed there.) They've talked about RPV's a couple of times in the past, but I've been able to successfully argue that everything was air gapped and no backflow preventer was necessary ... being air gapped here is an approved method. Everything IS technically air gapped except for where the hydrominder draws in the chemical, which is why I was asking the question. But if I can do everything for under $800, however, I may just go ahead and do it. It just irks me a bit that I have to spend the money (and future maintenance and inspections) for something that has virtually 0% chance of happening .. basically a fire has to happen that requires the hydrant down the street to be used causing suction at the exact same time that my hydrominder happens to fail. And even if that were to somehow happen, the amount of chemical that could be siphoned out would be extremely insignificant and immediately diluted and killed by the amount of chlorine the city puts in our water...but as has been said, it's tough to fight city hall.

And the RPV that I installed in 1998 -- it was inspected once in 2018..

 

[Earl Weiss]

Had a city plumbing inspector tell me once we could "Air Gap" Hydrominders by having the hose terminate above the liquid level in the bucket. Perhaps you can ask about that.

 

[bigjws]

Had a city plumbing inspector tell me once we could "Air Gap" Hydrominders by having the hose terminate above the liquid level in the bucket. Perhaps you can ask about that.

I'm not following you, Earl .. I'm thinking you are talking about the discharge hose, but the problem I'm having is that the city is contending the suction will still pull the chemical through the intake tube which goes into the actual soap bucket

 

[Randy]

I’ve see a lot of the Watts 009 RPV at car washes, they seem to be the most common at car washes. You can get a Watts 009 for around $800. There’s no reason you can’t install it yourself as long as you install it properly and have it tested after you install it. If you called a plumber and bought a RPV from him it will be a lot more expensive than if you bought it yourself, just be sure that whatever you buy is approved for your city. If you have multiple locations with RPV I’d try to have them all the same. I keep a repair kit for our RPV’s, you never know when they are going to start leaking. They are all repairable, the seats are stainless steel so they last a long time. When you install a RPV your going to see a 10-12 psi drop in water pressure, this is common.

 

[Earl Weiss]

Suction will not pull liquid thru an air gap, I guess the inspector who made this comment did not think the supply to the educator could pull back the concentrate - Then I would think the Hydrominder with the Siphon Breaker before the educator would solve the issue which is not to say the inspector would understand that or accept it.

 

[Randy]

What was the model you got for $600?

Yes, $2k was a ballpark figure because they wanted it buried out by the meter. I've since 'convinced' them that if I'm going to do this at all without a huge fight, it's going to be installed in the room, and they've agreed to that.

The wash has been here since 1982, and nothing was required at that time (we added automatics at a different location in a new building in 1998 and had to have an RPV installed there.) They've talked about RPV's a couple of times in the past, but I've been able to successfully argue that everything was air gapped and no backflow preventer was necessary ... being air gapped here is an approved method. Everything IS technically air gapped except for where the hydrominder draws in the chemical, which is why I was asking the question. But if I can do everything for under $800, however, I may just go ahead and do it. It just irks me a bit that I have to spend the money (and future maintenance and inspections) for something that has virtually 0% chance of happening .. basically a fire has to happen that requires the hydrant down the street to be used causing suction at the exact same time that my hydrominder happens to fail. And even if that were to somehow happen, the amount of chemical that could be siphoned out would be extremely insignificant and immediately diluted and killed by the amount of chlorine the city puts in our water...but as has been said, it's tough to fight city hall.

And the RPV that I installed in 1998 -- it was inspected once in 2018..

The requirement to have a Backflow device or RPV is part of the national plumbing code. It’s the water purveyor who determines what businesses have to have a RPV installed and which RPV to install, not all RPV are legal in all the municipalities and they usually go with the national standard. The water purveyor looks at how much potential a business has to contaminate the water system and they will always go with the highest requirements. The requirements change almost yearly, so what they might have told Earl in the pass might not hold water today. A lot of small municipalities have a very poor cross connect program that is a run by someone who has multiple duties and has very little time to run it properly. The guy who ran the program in the city that my car wash is located in moved to Montana about 12 years ago, I haven’t gotten a test notice since he left, I used to get one every year.

 

[Randy]

They never forget

They forget. I haven't had my RPV tested or inspected in 12 years. I rebuilt it about 3 years when it started leaking.