[robert mitchell]

I have just set up a static system in my shed using the outside tap.

its the 4040 from my van but i have just measured the flow from the tap and its around 6-7 litres per minute after the pre filter (brand new) and the pressure is around 20 psi.

with the booster pump going it gets to just over 40 psi when running at 60/40 waste ....... now at my ex,s house it would boost to 65psi (better flow from her tap) i can hear the pump cavitating when it runs so its not getting enough supply.


my question is , would i be better off getting a 450gpd system with booster ?

would a 450 run ok on a flow of around 5-7 litres a minute?

or a 4021 from gardeners?

would that run on that flow rate?

cheers

[Spruce]

I would start at the tap.

Is the poor flow and pressure just at that tap or does it also apply to the cold water taps in the bathroom and kitchen?

At that flow rate I can't see your toilet filling very quickly or the water will take ages to fill the bath.

If the flow is better from these other taps, then the problem could be at the point were the outside tap is plumbed into the main house pipe. (most outside taps are taken from pipe under the kitchen sink. They may use a special self drill clamp - such as this

http://www.screwfix.com/p/outside-tap-kit-brass-15mm-x/33139?_requestid=197859#

It could be there is a problem as the hole is too small or the tap hasn't be opened properly. This could also apply if the outside tap feed is taken from the washing machine supply.)

Here is a review from someone who fitted one of these.
""I am a plumber and bought this to 'save time' on a quick installation...wish i hadn't bothered. You get everything you need and decent price however had 3 problems -check valve was faulty so initially didn't work at all -near impossible to tighten up onto a pipe for the supply, the fitting kept moving and hence leaking -very poor flow rate, half what customer was getting on his other outside tap Only give it 2 stars as is decent value"

If your water flow is poor everywhere, then there could be the possibility that the water has been 'turned off' in the street. The previous tenant my not have paid the water bill so the water board turned the water off. (They aren't allowed to completely stop the supply.)

Do the neighbours also suffer with low water pressure? - just knock and ask is the best way to find out.
 

[robert mitchell]

i used to run it from the washing machine supply and through the kitchen window , same problems .

The rest of the taps are from a loft tank (on a new build!)

its a terrace and the outside tap comes from the loft and down the wall , this is new and was fitted by a plumber straight from the mains supply in the loft .

I'm the only person to ever live in the house so no previous tenants .

i believe the whole estate is the same .

When showering for a fair while the loft tank actually can't keep up and the flow slows to a trickle .......the water coming in is obviously not enough to keep up.

[Simon Mess]

You may have a problem with the mains supply. In my last house, the water pressure was very poor, i had it looked into, and it turned out there was a problem in the plumbing between the street and my house. I mention it because a booster pump is supposed to bring the water pressure up to a point where your r/o is at its optimum, i.e, if you have poor pressure. So if your pump is only bringing it up to 40psi, to me that suggests either the water supply or the pump is the problem, but you are saying the pump is working but not getting enough water through.

As for you 450gpd system, i don't think i would bother with that as i cant imagine, from what i have read on here, it would be better that a 4040. I have a 400gpd system with twin built in booster pumps and it since i purchased it about 18 months ago, the best it has given me is approx 1 litre per minute, currently more like .75 litre per minute.

[Spruce]

Then I might consider a smaller r/o.

My water pressure is 40 - 50psi and I get 13 liters of water at the r/o per minute.

I run my 4040 with an hf5 membrane and without a booster pump. Produces roughly 2 liters of pure to 2 liters of waste per minute.

I would wait and see what Alex says about his 4021 as that would require less water per minute than the 4040. Your booster pump might manage with that.

Failing that email him at

alex@agardiner.co.uk

as he might not be paying that much attention to the forums over the weekend.

[Spruce]

I think Simon has made a good point about the supply. I would complain to the water board and ask them to test your supply.

A smaller r/o takes longer to process the same amount of water. So that would probably be within his current taps capacity.

[Frankybadboy]

check that your stop tap out side in the road is fully open

[robert mitchell]

Been out to the pavement to check stop cock at meter .

It's fully on , it's a little plastic one that only turns a half turn from off to on .

[Spruce]

Maybe another solution is another 600 liter or 1000 liter IBC tank to be used as a 'header' tank or storage tank. You fill that with tap water and then use that water through your booster pump to filter water through your 4040. You might even be able to get away with a smaller 'header' tank as you could be processing water from this while still filling your main storage tank.

You could estimate this better by using water from your van tank. You could check the amount of water (LPM) your booster pump will pump at 65 psi which was your previous pressure. If its say 8 liters and you are supplying 5 liters from the tap, then you could get away with a header tank roughly half of the tank size in the van.

There was a company supplying a portable 4040 using a 5.3 litre 12v Shurflo pump as the feed pump and booster pump. This was enough to clean windows by directly processing it through the 4040, di vessel and then straight to the brush. We run our delivery pumps at between 1.5 - 2LPM when cleaning windows. (This again relates to the figures produced by my 4040 at 50 psi.)

[robert mitchell]

Thanks spruce , I already have the water processing into a 1000 little ibc .

I don't have room for a second one to feed it .

I have emailed the water company to see if they can test it .

If I have to go to a 450 gpd that's no problem .

It's easier to set up as an auto system with the 24v auto cut off pump .

Currently I have it set up as manual  which kind of defeats the object of a static system .

A controller is around 280 from gardiners or a pump with cut off 300 from machine Mart .

[Alex Gardiner]

On a standard set-up with a 35/65 product to waste ratio a 4021 HF4 would need about 9 lpm flow rate and a 4040 HF4 would need 23 lpm to work optimally.

I would imagine that either of the following units with a booster pump would be OK although the 4021 would be on its limits:

HF4/HF5 4021
450gpod
PRF-RO (5.5lpm flow needed)

[robert mitchell]

Sounds like a 450 gpd with booster may be my best bet .

Will this keep up with one man using 500 - 650 litres a day ?

Does anybody have the ro-man one with built in pump box ?

[Spruce]

Sounds like a 450 gpd with booster may be my best bet .

Will this keep up with one man using 500 - 650 litres a day ?

Does anybody have the ro-man one with built in pump box ?

A 450GPD just kept 2 of us in water using about 750 -850l per day. You will need to plan your water, especially toward the end of a good working week. This means starting off with full tank on the van on Sunday and having a full storage tank on Monday evening when you return home. Filling the van in the evening will give the system a head start to fill up overnight so you be able to keep on top of it.

Production in winter will drop due to water temperature, but then your working day will be slightly shorter as well.

Having an automatic switch on and switch off is ideal.

I would still concentrate on getting the water board to solve the low pressure/flow issue.

[robert mitchell]

I will try that first .

I did notice on a fish keeping shop website selling ro systems that they recommend a pump if you are on a water meter as the meter reduces the pressure .


http://www.ro-man.com/shop/index.php?route=product/product&path=22_92&product_id=4453

This is the ro I was looking at , pumped with a cut off float valve all for just over 500 .

[robert mitchell]

Hi , i have emailed the water board but got no reply ........as i expected !

Even though it says expect a reply within 7 days.

after investigating a bit more , the tap the plumber fitted had a double check valve incorporated in it , when looking at the inlet side of the tap it is very restrictive.

changed for a a tap without the check valve , yes i know your supposed to have one before you all start!

flow has now increased after the pump and pre filters to 15lpm .

This is less than the 23lpm that alex said is optimal for a 4040 but it gives me 4 litres per minute of pure water .

still only showing 45psi on the pump and it still sounds like its cavitating but seems to be doing the job.


tap pressure is still less than 20psi .

I'm wondering if its worth trying a new pump , a lot of money to spend if it turns out to make no difference.