Knocking in pipes after water heater replacement
Posted by Travis H Beaver on May 15, 2004 at 00:44:21:

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!


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