Cold Water Hammer? Stumped!

Old 08-23-05, 06:11 AM
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Cold Water Hammer? Stumped!

Newbe mistake, posted first under "Water Heaters" this could be a double post and against the rules, I'm sorry it happened, please excuse me.

I am on a water well system; have blatter tank at well, air pressure is 50psi; submersible pump 3/4HP with electric starter box; Pressure switch cut-in set at 42psi; cut-out pressure set at 49psi; copper piping within well area, turns into cpvc piping to house 50' distance.

The house is a converted from Mobile Home to house, have had well water for 30 years originally installed by a professional.

In the center bath area, when running cold water faucet or flushing the toilet I hear a dull hammer sound, cold water only, does not happen when using hot water, I can feel the "hammer" when I hold the cold water copper piping under the bath sink. Now the problem I'm having just started about a week to ten days ago and it's developing into a very large headache. When the hammer/studdering starts the lights flicker in all areas, house, detached garage (where the water well is located) and will continue to flicker until the shuddering stops. At the water pump location it sounds as if the pressure switch is trying to start, rapid clicking, sometimes as many as 18-20 clicks can be heard, and then the pressure switch turns on the pump and all is well until the cold water is used again and it starts all over again. I have had no water hammer/studdering before, so I'm wondering what would be the cause of it at the present time. I have no idea where the PRV valve is or if I even have one nor do I know if any air supply devices are installed within the water piping of the house.

I would greatly appreciate advice as to (1) Why it's happening at the present time? (2) Why it's affecting the lights to flicker while it's hammering? (3) What can I do to stop this problem? (4) Could it be the electrical starter at the well causing this problem?

Any replies would be greatly appreciated. Thanks in advance for your time.
Old 08-24-05, 08:11 PM
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reply to water hammer

You could have one of two problems. Either your pressure tank is bad causing the pump to short cycle. Or your pump control box is bad. Start with diagnosing the pressure tank, it's the easiest. Shut off the electrical to your well pump. Completly drain all of the water out of the pressure tank. To get an accurate air pressure. If you check the Air pressure the tank pressurized it always read what the water pressure is. If your cut on pressure is 42 psi. Your Air pressure with no water in the system should be set at 40 psi. always set the air pressure 2 psi below the cut on pressure. If that tests good chances are it is your Pump control box. You should be able to pick one up at the local do it center, or local supply house that could be open the public.

Last edited by wraytheplumber; 08-24-05 at 08:45 PM. Reason: not enough info

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