PRV, whole house filter, expansion tank

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Peter_6605

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winston salem NC
On Monday the fire department decided to exercise the fire hydrant outside my house. I am on the bottom of a hill and the last one in the cul-de-sac. Most of my neighbors are on well water so they did not get affected by the stupidity of the fire department. The fire department in their infinite wisdom closed the hydrant off so fast that it caused a hammer head effect that made its way all the way to my house. It destroyed my whole house filter and dumped water 1 inch deep in my shop. I have spent the last three days cleaning and lubricating my lathe, drill press and all my tools so they will not rust. So here are my questions that I need help with. I am trying to determine other than the whole house filter, what else did they damage in the water system. I checked the PRV and it appears to be working. I have it set at 50 lbs with the hose bib on and when I turn the house bib off it rises to 60 lbs.

Should it raise 10 lbs?

The expansion tank would be the next item. It is on my cold water line. I have the cold water shut off in the house, then the whole house filter, then the PRV, then the expansion tank. I checked the pressure in the expansion tank with the system down at zero pressure and it read 37lbs. I was told that it should be the same as the water pressure so I adjusted it up to 50 lbs which is my running pressure. After I turned the water back on I also rechecked the expansion tank pressure expecting it to increase to 60 lbs which is the pressure i the line when nothing is running. The tank was still at 50 lbs, This confused me so I let some air out. I dropped the air pressure all the way down to 40 lbs with 60lbs water pressure on the inlet side of the expansion tank. How can this be?

Is the expansion tank working?


And the final question has no answer - How to I prevent the fire department or city water department, who flushes hydrants, from destroying my plumbing system?

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I cannot speak specifically for WS or Forsyth County, but many municipalities flush and test hydrants on a regular basis (sometimes, like 2x per year) to ensure they are working (hydrant is nothing but a big faucet) and to flush any rusty water that may accumulate. So, if this is the first time it's happened perhaps some yahoo didn't follow a protocol.

Did you call the city and explain to them what happened? Maybe a pleasant phone call and showing these photos may get you some compensation. Worth a try! CityLink 311 or 336-727-8000.
 
I was very pleasant, yet upset when I called the water division. I had a manager come out and he was courteous and explain that their department was not out flushing the hydrants. It was the fire department that did the dastardly deed and they did not know which fire house was responsible. He continued to tell me that this happens regularly by the fire department and training is the only thing that can prevent it. This means any new rookie is prone to do damage and get someones blood pressure up. They did suggest to take pictures and send them in to risk management to request compensation.

So other than the water filter, based on what I explained do I have any other damage?
 
If you had other damage, you'd probably know it by now.

I'd have a word and meeting with the fire chief, and also the station chief with the fire station nearest to you, and get to the bottom of this.

What's with the galvanized piping? You ought to change it to copper or PEX. The galvanized will eventually give you trouble.

If this happens regularly consider adding a seriously large shock absorber or water hammer arrestor as the first thing in your water system. You may call a few of the manufacturers and talk to their engineers or customer service and explain your issue and ask for recommendations...
 
The water pressure at the hot water tank made it up to 70psi last night. Regulator is set at 60psi and drops to 50psi when you flow the water. Either I have a lot of thermal expansion that the expansion tank could not handle or a PRV that is leaking.

I am going to re-pipe the system and I can use Copper between the components. I am also going to move it down from above so it is easier to change the filter.

You mentioned a water hammer arrestor, isn't that similar to the thermal expansion tank?
 
You mentioned a water hammer arrestor, isn't that similar to the thermal expansion tank?

Well, yes and no. Generally the water hammer arrestors are small devices (see below) that are placed at the source of the hammer; more often than not, at faucets and most notably, at washing machines which are notorious for introducing hammer. (electric solenoids that instantly stop water flow). They used to be site made with just a vertical column of copper tube off a Tee just before the shutoff valve. Now they are manufactured items. The one shown is a set designed for use with a washing machine. Every faucet/fixture in both of my former homes had site made models. I have not checked the new house yet.

The expansion tanks should be able to accomplish the same thing--but in your case you had the filter before that tank and the filter housing got the shock first. My new house is the first home that has a thermal expansion tank at the hot water heater. Never saw this before in any of my former homes.

https://www.amazon.com/dp/B07DLPB9QS?tag=duckduckgo-osx-20&linkCode=osi&th=1&psc=1
And, oh by the way, whoever drilled holes in your joists to run that electrical wire? Done incorrectly; the holes should be in the center (or as close as possible) of the joist, not at the edge as shown. Holes at the edge weaken the joist. Your house isn't likely to fall down, and the joist isn't likely to fail--but next time remind the guy with the drill...
 
I have hammer arrestors at every sink, washing machine and inline inline in hot and cold water trunks in the house. I have copper tubes as shock arrestors in the wall for showers and bath tubs. I just never protected myself against the city.

Are you suggesting putting the thermal expansion tank first in line and use it as a hammer arrestor? Would it handle that type of shock?

The WS water department suggested putting a PRV out at the curb right after the water meter. I am thinking about it as a possible protection, but I have no idea what would happen to it if it was first inline to take the shock. And would I put a 3/4 in PRV in or up it to a 1"PRV. I have a 3/4" plastic line running to the house ?.

As for the holes in the floor joists - The person who built my house was an idot. No need to worry about a few small electrical holes like you said not ideal. I did end up with much worse like: floor joists that are not resting on the double top plate. (oh he forgot the double top and is not even directly above a cripple) Or a huge cut out in a floor joist because the drain for the bathtup was centered on the floor joist. I remolded the bathroom and moved the tub,

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You have a very unique situation that doesn't have a ready-made answer. You can't go to Home Depot and say "I need to buy a giant water hammer arrestor to prevent my pipes from bursting when the Fire Department flushes the hydrants".

I would call the technical departments at some of the larger manufacturers of equipment (Watts, Cla-Val, Emerson, Nibco, Zurn, Parker, etc.) and also those professional engineers best suited to solve this issue. Try making some phone calls to get some referrals to those you may be able to talk to. Aside from that list of manufacturers, try this group:

https://www.pmengineer.com
 

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