House Water Pressure Pulsing After Shutting Off and Draining Water from Detached Garage/Apartment

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Tom2020

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Hello,

I have one well that feeds both my home and detached above garage apartment. The apartment is not occupied at the moment so I do not want to pay to heat it. To prevent any pipes bursting I shut off the apartment's main water supply and then drained the building of all the water. Immediately after I noticed the water pressure in my home was pulsing full pressure to half pressure in consistent 5 second intervals. I turned the apartment water back on and refilled it, after which the pulsing stopped. As far as I know there is no link between the apartment and house water lines other than the main well they are both connected to.

Does anyone have any ideas on what could be causing this?
 

Tom2020

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There is a pressure tank in the apartment it's small and plumbers have told me they don't think it is connected to the house. Nobody has ever found another pressure tank, I was told the house only gets preasure from the pump. I am saving to get the whole system replaced. We wont really know what's going on until they dig everything up.
 

Tom2020

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So shutting off the apartment water takes away the only pressure tank the system has and that causes the pulsing?
 

Jeff Handy

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johnjh2o is right.

The well pump is cycling so fast because there is no pressure tank to help push the water out when the pump shuts off.

So when you open any faucet the pressure drops quickly and greatly, so the pump has to come back on every few seconds.

You can add a tank somewhere in your house, anywhere close to where the well water line comes in.

And you should keep the apartment heat on but just keep it low, like 45 or 50 degrees.
There is often water trapped in the lines, and that can freeze and require expensive repairs.

Even if you blew out all the lines with compressed air, water can still collect in low spots.
And the drain traps can freeze also.

Also, if the apartment is totally unheated, condensation can form on or inside the walls and other places, resulting in mold or water damage and paint failure.
 

Valveman

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Yeah well the pressure switch should be located with the pressure tank. If closing off the apartment kept the tank from being in the circuit, it should have also kept the pressure switch out of the circuit. This means you pump should not have come on or gone off, as the switch was isolated. Large pressure tanks or multiple tanks are no longer needed. With a modern constant pressure system like a Cycle Stop Valve a little 4.5 gallon size tank is all that is needed for an average size house.
 
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