Post by londonman on Feb 19th, 2017, 3:00pm
We get our water from a borehole and it's then treated down in the cellar. An annoying problem has been creeping in over the last few days in that the cold water in the house stops flowing. It's all driven by pumps in the cellar and when you turn the tap on, you can hear the pump kick in.
This is the pump and what? Pressure tank as it's a negative head ?
The tank does have a meter on it and when the water stops (because the pump s not energised when the tap is turned on) I notice that the pressure on the meter has fallen. To get round the problem, I momentarily open up this stopcock here and then the pump starts and the meter on the tank shows increased pressure.
I don't really understand how these things work. Does the tank have a diaphragm inside it with air under pressure on one side and water on the other ? If the pressure is dropping then what? A pinprick hole in that diaphragm? How can I tell?
What if there was a slow leak in the cold water system somewhere ? A leaky cistern stopcock, for example. I could see that slowly reducing the pressure such that when a tap was turned on there was not enough pressure inside the pressure tank to start the flow to make the motor run.
Have to confess that I don't really understand how it turns on and off....pressure sensitive switch as opposed to a flow magnet like to get in shower pumps ?