Town Water Supply

nomad97

nomad97

Resident Geek
Johnb said, "All that rain last evening and we wake up this morning to very, very low water pressure. The wife saw on Facebook that something is broken at Hoi Senang. Anyone else got problems?"

In a word, no. We live on the outskirts of town and there is a reasonable flow of water in the inlet pipe to our holding tank. Maybe there is an insufficient 'head' of water to top up the tank during the day but the tank is full and usually recharges every night.

Are you saying you do not have a water tank between the water inlet from the town and distribution to the house ? Do you rely solely on the town's municipal water supply? If so, you have been very lucky to have a continous flow of water. I have a 2,100 litre tank and a Hitachi electric pump to distribute the water under pressure to the house. I have always needed this setup for the past 12/13 years to ensure an adequate supply of water 24 hours a day.
 
John said 'very, very low water pressure.'

The question to 'does he have a pump' must be ascertained before further investigation.

It's all yours , John...as you're wondering as to why.
 
nomad97 said:
I have a 2,100 litre tank and a Hitachi electric pump to distribute the water under pressure to the house. I have always needed this setup for the past 12/13 years to ensure an adequate supply of water 24 hours a day.
Click to expand...

I have the same set up but a 1 m3 holding tank (good for about 3 days if there's a stoppage).

water supply.jpg
 
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I had a similar set-up in Chiangmai. In the dry season, mains water was often cut to three or four hours daily, and the holding tank was essential.

The square metal covering was in our front yard (a townhouse). One day, our Bangkaew dog somehow managed to shift this, and fall through into the tank. Luckily there was a severe water shortage at the time, or he would have drowned. Nung came home to find him there, and had to climb down into the tank himself to rescue the dog (in a right state of panic). As the silt from the mains water had accumulated at the bottom, both Nung and dog were covered from head to toe in mud before they got out.

Luckily I was away at the time, or else Nung would have made me do it.
 
Nice diagram Yorky - I have the same but without the by-pass. Tried it to start with but the pressure was insufficient for the hot water shower. Your diagram needs a non-return valve on the by-pass loop to stop the water flowing backwards when the pump is on.
 
We have quite a bit of silt build up in our tank also. Since we changed onto "mains" water (about 7 years ago), my wife has been in the tank once to clean it out. I have screwed connectors at strategic points on the pipework to facilitate disconnection of the tank and lay it on its side.

Out of interest does anyone drink the mains water? I have an under-sink filter in the kitchen and use tap water for coffee, tea, boiling vegetables, making gravy - virtually everything that requires the water to be boiled. Also, washing dishes and cleaning work surfaces, etc.

In the bathrooms, we use unfiltered water for teeth cleaning, showering, toilet flushing and hand washing.
 
nomad97 said:
Your diagram needs a non-return valve on the by-pass loop to stop the water flowing backwards when the pump is on.
Click to expand...

There is a valve on the by-pass which is in the closed position unless we have a power cut, at which time the valves at either side of the pump are closed and the by-pass valve opened. As you say there is minimal flow during the day but any water is better than no water. Evening time there is just sufficient to shower.
 
There's a pressure sensor on the outlet. >1 barg (I think) shuts it down. We have a standard ball cock in the tank (inlet is very close to the top). Completely turning off the pump electric supply is by a switch on the consumer unit.
 
maybe I'm missing something here,
but does this setup mean that if the mains supply is cut for some reason and you have a leak or an open valve
in the house the pump will just run and run and run, pumping air or whatever?
 
If we have a leak of a magnitude to permit "full bore" flow, then the pump will run forever or, in the case of mains water being shut off, until the tank is empty and the pump cavitates and/or burns itself out. This is unlikely to happen as whenever we leave the house to stay away overnight, the electric supply to the pump is manually shut down. If there is an occurrence overnight when we are in residence, the pump is immediately outside our bedroom window and I'm sure the continuous running will awaken my wife.

[If, in the unlikely event that the mains water is cut off and we have a leak at the same time that we are shopping or out at the pub for longer than it takes to empty the tank (6 hours?) then it is "new pump time"].
 
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Reminds me of a project we had in the North Sea where it was a requirement that we transported full nitrogen tanks offshore to purge and fill an underwater pipeline. The Client's consultant required a "contingency procedure" in case a tank ruptured. I told him there was only so far one could go - would he next require a "contingency procedure" in case the vessel sank!

[Edit: He didn't get either]
 
melvin said:
maybe I'm missing something here,
but does this setup mean that if the mains supply is cut for some reason and you have a leak or an open valve
in the house the pump will just run and run and run, pumping air or whatever?
Click to expand...

1. Water flow into the tank from the mains inlet is controlled by a simple mechanical float valve. Once the water reaches the desired level in the tank the ballcock shuts off the flow of water.

ballcock.png

2. As far as the water pump is concerned this is controlled by an automatic sensor in the pump. When you turn on a tap, or flush a WC, the drop in water pressure will be sensed by the pump. Initially, the pump will satisfy the demand through water already under pressure in the pump. Once this is consumed the pump will start up and pump water under pressure to the outlet. Once the need is satisfied, and the open tap is closed, the pump will automatically shut off.

Buriram Hitachi Inverter WM-P750 GX automatic water pump.jpg

3. Finally, you are quite correct that if you leave the tap open, or there is a leak/break in the pipe, the pump will continue to work until such time that all the water has been pumped out of the holding tank. Could make quite a mess and flood your house if the break is inside the house. However, the same would happen with water coming directly from the mains without a holding tank and pump. Water would continue to pour into the house until such time that the pipe is sealed or the tap is closed. That is why it is very important to have an in-line tap or valve, commonly called a stopcock, as the last point of entry into the house. This can be shut off to allow repair work to be undertaken on the broken pipe.

stopcock.jpg

I could add, in the examples that we have shown here, switching off the electrical supply to the pump would also stem the flow of water. When we have a power cut we also have no water flow into the house. Fortunately, power cuts are now very infrequent.
 
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nomad97 said:
That is why it is very important to have an in-line tap or valve, commonly called a stopcock, as the last point of entry into the house. This can be shut off to allow repair work to be undertaken on broken pipe.
Click to expand...

My "stopcock" (denoted "remote valve" on the sketch) is a pair of hand operated valves both sides of the meter outside the gate.

[PS: pretty girl - I have the same make of pump but mine doesn't have any ears].
 
Another reason for inserting a holding tank between the town's water supply and your house is all the suspended muck in the water. I just turned on the outside tap to fill the dog's water bucket (she's a big dog) and the water was very brown. I took relatively clean water from the tap after the holding tank. About 4 years ago I had to drain the holding tank to move it to our new house. There must have been several inches of sand in the bottom that had settled out over the previous 7 years or so. The water outlet pipe is about 12 inches from the bottom of the tank. Don't be tempted to plumb into the bottom drain plug.
 
We have town water and village , town has more pressure but we are often swapping taps over as one stops or drip drops ☺ .
Pumps and tanks are a good idea but lucky for us we don't need and that's good for power cuts , we can shower in the dark .
You can always by pass the tank and pump for the power cuts .

Sent from my SM-J700F using Tapatalk
 
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