[pcrouch666]

Hi all

We have a private water supply.

Our water comes from a well up the hill so feeds to a 200 ltr holding tank next to the house. We then have a pump which draws from the holding tank and pumps the water into the house.

The trouble is is when we use the upstairs shower / tap the water pressure is not great, and if someone uses water downstairs it becomes almost non-existent upstairs.

The holding tank has around a 4 inch pipe that leads into the pump and the pipe that comes from the pump to the house has around a 1 inch bore.

I have no understanding of water pressure at all so please excuse the 'dumbness'. Can I 't' off from the 4 inch pipe into another pump and 't' back into the 1 inch pipe that goes back to the house. Or can I just get another pump with more power to help increase the pressure.

Any advise would be great.

Many thanks for any help.

[Womble]

How high is the holding tank relative to your house? (same level?). Also how far below the tank water level is the pump, and roughly how long is the pipe between the tank and the pump?

Can I 't' off from the 4 inch pipe into another pump and 't' back into the 1 inch pipe that goes back to the house.

I may not be following this properly, but do you mean so that you have two pumps running in parallel with each other?  If so, that's probably not going to help you very much TBH. If you want more pressure, generally you have to put a second pump after the first, but there are potential issues with that which would be hard to predict without seeing the system first hand and doing some calculations.

Do you have a pressure gauge anywhere in the system?  If so, it would be really handy to know what it reads under different flow conditions. Also, what's the make and model number of the existing pump?

Or can I just get another pump with more power to help increase the pressure.

Yes, you can certainly do that. However, before you do, it's worth giving the existing system a check over to make sure it's not something obvious first. Also, if it IS something wrong with the rest of the system, and you change the pump without fixing it first, your problem is very likely to remain!

Sorry to ask more questions than I've given answers to, but if you can expand a bit, maybe I can be more helpful later?

[pcrouch666]

Thats great help thanks.

The holding tank is at the same level as the houses ground level, the pump is at ground level too. To get the water upstairs I'm guessing it is just using water pressure.

The distance from the holding tank to the pump is about 12 inchs.

The system is all ok as it was checked last year.

I'm thinking that the more volume of water I through at the pump (s) the more pressure I can get from the pump at the outlet end. ? I really don't understand how this water pressure thing works. lol

All your help no matter how many questions is very helpful trust me.

Any more advice is greatly welcomed. PLEASE !

[pcrouch666]

My mistake, I was thinking it was the old system on our other house.

I have attached photos to see if you can get a better understanding of our problem.

Many thanks

[henchard]

we have a similar system. However, a holding tank of 200L is not a lot (if it cannot refil quickly). Ours is 3000L. Average water consumption is around 150L per person per day; so if it's not refilling quickly enough there could be a problem.

We had a problem when the pipe from our spring to the holding tank being blocked with sediment.

We had to clear it by blowing it back with a compressor.

Is the pressure guage on the pump in PS!? Ours is set at around 3 Bar which is around 44 psi and this gives us plenty of pressure. If some pumps have been allowed to run dry for any time the vanes can overheat and distort and then the punp cannot produce much presure.

Are there any inline filters anywhere that need cleaning?

[Womble]

Ah, that's a bit different, having seen the photos.


The pump looks like a good spec, so provided it has water to take (as Henchard says), and as long as there are no blockages, it should be fine. What actually tells the pump to turn on and off?  Is there a pressure switch somewhere near the wee blue tank perhaps, or one internal to the pump?


One thing that concerns me a little is the inlet pipe to the pump. It's nice and short, but is that a 15mm valve on the outlet to the tank?  Couple that with the non-return valve, if that's what it is, after the blue plastic section and I think you may just have too much pressure drop in the pump suction pipework.


If this is the case, the pump will most likely be quite noisy and the flow will be poor. If so, try gagging back the outlet valve to very nearly closed when the pump is running, and see if the noise disappears. If it does, that points to a restriction or blockage in the pipe between the pump and tank.


Has it ever worked well to your knowledge? (i.e. has the performance always been poor, or has it deteriorated over time?).

[pcrouch666]

Thanks both. Sorry it is a 2000ltr tank not 200 oops.

I will try your suggestions.

We do have two filters inline inside the house, I will check they are clean.

I was thinking, if I changed the pipe from the tank to the pump to a larger bore, would that help increase the pressure ?

The pump runs after about 6 seconds of running water so I'm guessing there is a pressure valve in the pump. (?)

I'm not 100% sure about what the blue bottle thing does, its filled with just air. (?)

I will let you know how I get on.

Thanks again

[henchard]

The pressure vessel (blue cylinder) is charged with compressed air (and needs topping up now and again) it is used to provide a reserve of pressurised water to limit the number of starts of and wear on the pump.

The pressure switch will cut in when the pressure drops below a preset point starting the pump and cuts out when the required pressure is achieved. You can tell when pressure in the vessel is getting low as the water flow starts to 'pulse' in the house.

A larger pipe will not change the pressure but can allow more water to flow through the pipe.

[pcrouch666]

Thanks.

I have checked the filters in the house and although a little clogged, now changed for new ones, it did not change the pressure upstairs.

I watched the pump and it sits at 75 psi and when the water is running it slowly drops to 50 psi at which point the pump cuts in and when the water is switched off it runs until it hits 75psi again.

The air cylinder is good with air, I had ALL PUMPS come out once when it seemed full of water and they fixed it.

In regards to what Womble was saying, the pipe from the water tank only has a open/close valve on it I don't think there is a non-return valve on the inlet. Let me know if you think I'm wrong. I'm new to all this.

When I run the pump and close the shut off valve slightly the pump gets louder, I think it is starved of water.

I was thinking along the lines that if I give the pump more chance to take water in then maybe it could pump harder because it has more water available than it can push through the outlet. Am I wrong. (?)

We've got an outside tap and that seems to have more pressure than the indoor taps, does that make you think I have something in the house which is controlling the pressure through the house. The outside tap 't's off after the pump but before the indoor stop tap. Hmmm

Any thoughts

Cheers again 

[Womble]

I was thinking, if I changed the pipe from the tank to the pump to a larger bore, would that help increase the pressure ?

Only under certain circumstances (technically, only if the pump doesn't have adequate "net-postive suction head", or NPSH).
 
I wondered if this might be the case for you, hence the test with closing the outlet valve. What that does is to reduce the flow the pump is producing, which reduces its requirement for NPSH. (If a pump runs noisily, but quietens down when you dead-head it, that's a good indicator that the suction pipework has too much pressure drop, and needs to be enlarged).
 
However, from what you just said, I don't think that's what's happening here.
 
If your pump is running between 50 and 75 psig, that's roughly 3.5 to 5 barg: more than twice the pressure in a car tyre, and technically enough to pump to the top of a six-storey house!
 
That pressure must be going somewhere, so I think you must have a blockage or other restriction somewhere inside the house. If the pressure to your outside tap is good, that also supports this theory.

[pcrouch666]

Thanks, with the information both you and henchard have offered me I am thinking along those lines too.

Maybe the waste of space plumber that we had re-pipe the house has put some sort of pressure control onto the system. I don't think its a blockage but I will obviously check the system. I will see if I can get a proper plumber in to look over the system and see if they can see what this mass of stuff actually does.

In the house the original plumber put a small hot water tank and some football sized round orange cylinder in, god only knows what that does. It may just be for hot water or heating. We also have a small pump and some sort of electrical metal box on the system.

But if anything is controlling the flow of water maybe that is where we are losing pressure.

Thank you both again for your help it has been invaluable for my understanding of our water system.

Cheers