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Auto shutoff Valve on Loss of Pressure

Auto shutoff Valve on Loss of Pressure

(OP)
I have some property in South America and we loose water at least once a week. Once the water returns, we need to flush the system for at least 10-15 minutes to clear all the dirt/mud out (as they do repairs, it get's filled with earth). We don't drink from this source....

I'd like to not have to flush this in our sinks/showers or toilets (if someone's not paying attention), plus, we'd like to install a reservoir barrel to keep some water available....which takes water on low level automatically.

Is there a valve that will close on loss of pressure and needs to be manually reset? I'd install a diverter just upstream of this valve to flush the system outside of the home after the 'loss of pressure' valve closes. Once flushed, I would manually reset the valve. Incoming line to the property is 20 or 25mm PVC.

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RE: Auto shutoff Valve on Loss of Pressure

For PVC that small, your best bet is probably a check valve and ball valve combination. When service is lost, you'd need to manually close the ball valve to prevent flow into your system when service is restored. The check valve would close on the loss of forward flow and also serve to prevent backflow from your reservoir into the water main.

RE: Auto shutoff Valve on Loss of Pressure

I think you have a couple options

1) 3 way ball valve with upstream pressure switch
2) Relief valve set at desired pressure. When low or no pressure, no flow to your house. Still requires separate flush/drain and still a risk that once pressure returns, it'll flush dirt downstream
3) Might be able to do something clever using a piston with water pressure on one side and compressed air on the other to keep a normally closed valve to your house open when there is pressure and closed on low pressure. Once the air has been lost on the de energise stroke it needs to be mechanically filled again. This will prevent forward flow of dirt when pressure returns

RE: Auto shutoff Valve on Loss of Pressure

The easiest, considering you're a sparky, is a simple pressure switch and solenoid valve via a manually resettable relay. Then you can adjust the pressure switch to your desired valve and prevent inadvertent operation.

ditto your standby water source - use some float switches and a set of solenoid valves.

You might find something already packaged together, but I've only seen it for gas supplies so far.

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RE: Auto shutoff Valve on Loss of Pressure

(OP)
Standby water source is already done - essentially a toilet/float type mechanical valve. We just don't want it to get filled with dirt. When we loose water, we take water from the standby source. The standby tank is set on top of the house, so everything is gravity fed when we loose water pressure.

I had thought of the pressure switch and solenoid...but we loose electric quite often too! I suppose make it a fail open valve, or fail close with a manual bypass for when we loose electric. We're up in the mountains in S. America. I was surprised we even had city/municipal water....

Now the hard part is finding parts down there....

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RE: Auto shutoff Valve on Loss of Pressure

Maybe this combined with a pressure switch?

Loss of power, either loss of power or loss of pressure latches closed

http://www.asco.com/ASCO%20Asset%20Library/asco-se...

Remember - More details = better answers
Also: If you get a response it's polite to respond to it.

RE: Auto shutoff Valve on Loss of Pressure

(OP)
Thanks LittleInch....More what I was looking for. I wonder if they have anything like this in a Pilot Valve, where loss of the pilot pressure would close the valve too. I'll check further...

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