Water Pressure Problems

[TexasRanger]

Hi,

My new house was just finished and I have a few water problems. I won't go into the why's and wherefores but the bottom line is that I had a water tower built, and a fine specimin it is too, here are some pictures, you can see that at 5m height plus the tank it tower over the house, the pipework from the base of the tower to the house is not more than 4m to the first tap. Pictures

What happened is that thee water pressure was so low that when any of the taps were turned on it came out slowly, the kitchens indoors and outdoors are closer to the tank than the bathroom and are a bit stronger but not much, the shower and bathroom sink are pathetic.

To cut a long story short I had to add a 280W pump after the tower and that makes everything fine.

It has however started to bug me as to why when the pump is off (power cut for example) I can't get decent flow from such a tower?

As it is all taps including the one nearest the tank I am thinking maybe some kind of partial blockage from glue or general crap (cement?) that the pump is able to push past but the water flow without the pump can't bypass? I am thinking of cutting out some of the pipe and replacing stuff to try and isolate the problem.

Any info gladly received as I am not a plumber, also (forfgive my ignorance) I take it there is not much more to connecting these pvc pipes than making a clean cut, cleaning off the burrs and glueing??? Should I put glue on the inside of the larger pipe or the outside of the smaler or both and should you leave it a certain time before letting water flow after glueing?

Thanks in advance,

Frustrated of Nakorn Phanom

[trogers]

I estimate you have only a 6m water head from middle of your water tank to the faucet.

Converting height to water pressure

1 psi = 2.31ft

20ft = 8.5 psi

Assuming you have no problem with blockages in pipes and fittings, water flow will still lose pressure due to friction loss over distance. For a 1-inch pipe over 10m, 8.5 psi may become 7psi.

Normal faucet are designed to work well with 1 bar pressure (or 14 psi). You are only getting half of this pressure. Water heater and larger faucets like flush valve need 1.5 bar.

Thus, the reason for the pump.

[Gary A]

I have a similar situation. Your tower is not high enough to have decent pressure. It is, however, high enough for most things. I installed a pump for the bathroom. It supplies the shower, toilet and washing machine. It takes water from a ground level tank and is a totally separate system. The tower supplies the kitchen and outside taps for watering the garden etc.. There is a valve that I can open to supply the bathroom if the power is off. It doesn't have enough pressure to trip the pressure switch for my hot water shower but there is at least water.

Bottom line is that you don't want to run the tower water through the pump. Add a "T" to the discharge side of the pump with a valve. When the power to the pump is off, open that valve.

[TexasRanger]

Bottom line is that you don't want to run the tower water through the pump. Add a "T" to the discharge side of the pump with a valve. When the power to the pump is off, open that valve.

Thanks for the info, but why don't I want to run tower watter through the pump? Does the pump restrict flow if it isn't powered?

I have one pump which sucks from the well annd supplies the tower then the pipe that comes out of the tower has the biigger pump at the botttom which supplies the house.

Edited March 1, 2009 by TexasRanger

[trogers]

Does the pump restrict flow if it isn't powered?

Yes.

We usually have a bypass that will be used should there be a power blackout or if you need to remove the pump for servicing.

There would be a gate valve before and after the pump to enable it being removed for servicing or replacement.

Connect a pipe (with two 90-degree bend) before and after these 2 gate valves. This bypass pipe should also have a gate valve which is only opened when you bypass the pump.

Edited March 1, 2009 by trogers

[TexasRanger]

Does the pump restrict flow if it isn't powered?

Yes.

We usually have a bypass that will be used should there be a power blackout or if you need to remove the pump for servicing.

There would be a gate valve before and after the pump to enable it being removed for servicing or replacement.

Connect a pipe (with two 90-degree bend) before and after these 2 gate valves. This bypass pipe should also have a gate valve which is only opened when you bypass the pump.

Thanks very much, I will do that, the longest run is to the bathroom, if I was to isolate everything else and supply only the bathroom in the event of a blackout would this help with the bathroom flow or not?

[trogers]

Thanks very much, I will do that, the longest run is to the bathroom, if I was to isolate everything else and supply only the bathroom in the event of a blackout would this help with the bathroom flow or not?

Water supply without the pump will still be half the ideal pressure. Best way is to bathe like the locals, have a clay urn filled slowly with water and use a scoop.

[Rimmer]

What a beautiful thing to have in your garden

[trogers]

What a beautiful thing to have in your garden

But it cannot beat the Balinese outdoor toilet...

Edited March 1, 2009 by trogers

[TexasRanger]

Whilst diggging up the pipes to see where they enter the house I have found that I have 1 inch pipes coming from the tank and then they reduce in diameter bevfore they enter the house, is there any benefit to making the pipes 1 inch until just before they go through the walls, would this help the flow or am I still limited by the height of the tank? Cheers.

[trogers]

Whilst diggging up the pipes to see where they enter the house I have found that I have 1 inch pipes coming from the tank and then they reduce in diameter bevfore they enter the house, is there any benefit to making the pipes 1 inch until just before they go through the walls, would this help the flow or am I still limited by the height of the tank? Cheers.

From what you have described earlier, you basically have 2 water points in your house - wet and dry kitchen, and a bathroom. The 1-inch pipe may be reduced to 3/4-inch to serve 2 water points.

Should you need to extend one or two more water points in the future, make sure you use a 3/4-inch pipe for the new extension.

Pressure is primarily being limited by the height of the water tank. For working pressure without the pump, your tank has to be 20m above ground level.

Edited March 2, 2009 by trogers

[Artisi]

The height of the tank is the controlling factor but as you have 1" pipe upto the house it just means that the loss to this point in mimimal. As trogers pointed out earlier - the pressure here can only be approx maximum of 8PSI, from this point on if the pipes are 1/2" then you will incur higher losses.

The achieve any meaningful pressure inside the house you will need to install a small pump unit , close to the house is probably the best point as it will save on power cable.