Re: Knocking in pipes after water heater replacement
Posted by Sylvan Tieger on May 15, 2004 at 12:04:08:
In response to Re: Knocking in pipes after water heater replacement
: Hello!

: We had our water heater professionally replaced with an A.O. Smith Conservationist 40-gallon tank in 1999.

: As soon as this unit was put in place, we get frequent loud knocking/rattling in our pipes when the water is running. It is the worst when cold and hot are on at the same location (i.e. the washing machine on "warm").
: When the location is turned off, you hear one loud knock followed by one or two quieter ones.

: Our plumber who put it in said we have a loose pipe somewhere, but why would this have started the day he put in the tank? All pipes around it are tight as can be.

: Another plumber thought it was air in the line, so he installed a baffle in the line...and this didn't help at all. We recently had our water pressure reducer replaced, and this didn't make a difference either.

: Thanks for any advice you can provide!

: Travis

Wow "air in the line" that is a great one I must use it to get folks to buy parts.

If air gets into the line how come water doesn't shoot out of the same opening?

Is this water supply on a negative system sucking air through valve bonnets?

I would install an AIR CHAMBER to see if this hydraulic shock absorber to see if this helps.

Shut off the water supply to the washing machine one at a time (H&C) and then test to see if it.

As there could be a bad Solenoid valve as any quick closing valves like some ball cocks can cause this kind of sound ALSO a loose washer can send sound waves through out the system.

Check your piping to make sure it is properly strapped so it does not move especially on long runs.

ALSO check to see if someone had installed a return circulation line with a check valve, this is another problem a check can cause.

Personally I think its a combination loose piping and a quick closing valve

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