Water Pipe Hammering

tinner666

Hey guys. I don't hang with you plumbers too much, but I have a couple of queations.
About 2 weeks ago, when the toilet got flushed, the pipes started hammering. Only did it at random intervals, and not every day. Yesterday, it hammered several times.

What causes it? ( We've been here 16 years without it )

The city has been working on the local water lines for about 2 months. Could they be causing air bubbles, which in turn are causing the hammering?

FWIW, they're digging at nearly every corner, and appear to be inserting new liners in the pipes, or maybe dragging 'a bullet' through the lines to clear them. Been low pressure here for years.
Above ground 2" lines everywhere, hydrants open and runnning every few corners. Steady flows, low pressure with them too.

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Frank Slate Roof Repairs, Richmond, Va.

Ron The Plumber

Sounds like the fill valve on the tank has seen better days, time to replace it.

Whats so wrong with hanging with us plumbers, you have something against us?

KillerToiletSpider

How old is the house?

Does it only happen with the one fixture, or do you get hammering when other fixtures are used?

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A flush is better than a full house.

tinner666

I've got nothing against plumbers! Been under many a house sweating pipes, cleaning out sewer/waste lines. Even melted lead and packing into cast iron pipe a few times.

House about 50 years old, 1 bath. Random events of hammering.

Which is the fill valve on the tank? Are you talking about the 1" tube the float is attached too? I'm familiar with 99% of the parts, but not the nomenclature for each.

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Frank Slate Roof Repairs, Richmond, Va.

KillerToiletSpider

Yes that would be the fill valve, but if it happens when other fixtures are used, it is probably not the fill valve. It sounds to me like your air chambers are water logged. Does the house have the laundry room in the basement? If so there is an easy fix, turn off the water main to the house, then go to the laundry sink and open the hot and cold on the faucet, then go to the bathroom and the kitchen and open those faucets as well. When you no longer get any water out of the laundry sink, turn all the faucets off, and open crack open the water main, and let the system fill back up slowly. This will restore the air into the air chambers and stop the hammering.

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A flush is better than a full house.

tinner666

Great. Thanks for the quick reply. No sink in the laundry room, just the washer. And 1 line for the outside faucet. I'll see what I can do later tonight, after supper. Thanks.

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Frank Slate Roof Repairs, Richmond, Va.

tinner666

OH, the laundry room is behind the bathroom, but it is 2' lower than the bathroom.

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Frank Slate Roof Repairs, Richmond, Va.

KillerToiletSpider

Shut the water main down and drain from the drain on the water heater, it would be the lowest point, but you will have to drain it for awhile, about a half hour oughta do it, and you would be doing your water heater a favor.

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A flush is better than a full house.

tinner666

OK. No key here, so I'll have to put it off till Sun. then. Going out of town tomorrow, and key is at shop. Can't turn my valve off with a wrench.

I apprectiate your replies. Many thanks.

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Frank Slate Roof Repairs, Richmond, Va.

Ron The Plumber

If that is an electric water heater, make sure to power it down or you will fry the elements out, and if gas shut the gas off or set the pilot only. Also do not turn power back on the the heater if electric until you get all the air out of it, do this by opening up a faucet on the hot side, once the faucet stops spitting air then you can fire the water heater back up.

Just info you should know, no one has mentioned this yet.

KillerToiletSpider

Good point, I always assume people know to do this.

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A flush is better than a full house.

tinner666

Thanks for the reminder! It's the first thing on my list. Electric.

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Frank Slate Roof Repairs, Richmond, Va.

Grumpyplumber

Sherlock Holmes here...

Recent / current work in the street main. Low pressure for years.

Water hammer suddenly occuring.

Let me guess...new homes popping up alot in your area?

JUST a guess...stab in the dark here:
Local DPW finally decides to boost pressure from years of complaints...keep up with increase in demand (have a plumber put a gauge on your main...look for pressure exceeding 80 psi)

IF thats the case...have your plumber start with an expansion tank (IF the pressure is high)
IF the tank doesn't quite cut it...have him add a PRV

Just seems like too much coincidence that the water mains are being reinforced...but with what you've mentioned it's an educated guess.

tinner666

Grumpy. My concern exactly! But, we still have low pressure and no sign of any higher pressure yet. At all. Since I've been remiss in draining my WH for years, I'll drain the system before trying anything else. It's necessary anyway, and will be a way of eliminating one scenario.

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Frank Slate Roof Repairs, Richmond, Va.

Grumpyplumber

It's a good idea to drain every 6 months or so...and the idea hadn't occured to me, but thats a perfect start.
I'm still wondering about your pressure issue though...you can still have good pressure with bad flow and get low volume...one sign is the faucet starts with briefly good flow or surges when opened, then slows down...this could mean you have constriction in your water lines...very difficult to cover all variables in typing.

tinner666

No surge when turning any faucet on. I cut power, opened drain, turned all faucets on,and drained the tank. Took over an hour to refill. Left hot valves open enough to drip. Turned power back on. We'll see how it turns out. Hammering was random and days would go by between events. So now, it's just wait and see.

Thanks for all the replys! This place has always seemed to have great group of people.

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Frank Slate Roof Repairs, Richmond, Va.

tinner666

Hammered today. I'll be getting a new inlet tomorrow~

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Frank Slate Roof Repairs, Richmond, Va.

tinner666

Many thanks for your responses guys No hammering after changing the inlet and a loud whine which had also started at the same time has disappeared. Thanks,

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Frank Slate Roof Repairs, Richmond, Va.