Ping Nick Holmes re Water Softener.

[Donwill]

[Copied & Pasted from "Reccomendations for a decent boiler etc]

Pls excuse the slight tangent but I want to replace our existing boiler before winter. Ideally I would love to install a softener too but I have always worried that the softener would restrict the flow/pressure.

We have quite low mains pressure in Cambridge, typically 2.5 bar, this correspondingly delivers only about 20L/min at ground floor on cold mains but a disappointing 10L/min in our second floor bathroom.

Clearly, Don, you are very happy with your shower now but I wonder if you think your water supply and situation means that the softener could be accommodated better in your supply than it would work for us?

What kind/make did you use - I have noticed some are limited to 1.75 bar?

Any tips/info gratefully received.

best wishes

Nick

Hi Nick, Sorry about the delay in answering your query, however here goes. I purchased the water softener from EMWC in March this year, a Permutit model, although most of them seem to be made by Culligan these days but I had the permutit branded one for historical reasons I suppose. Here's the link to the one I purchased.

was installed and commissioned in May and has been on stream since then and given satisfactory results. There are only 2 of us in our house so the demand on it is quite small, however, we have used approx a bag and a half of salt to date ( we buy localy at £10 a 25Kg bag). Our incoming water is approx 230ppm of hardness and it reduces it to less than 14ppm after regeneration, there is a mixing facility valve built in to the unit which allows you to mix the incoming hard water with the softened water to allow you to choose a not so highly softened water if you require. We have not chosen to do so.The water pressure is controlled to 3.8 Bar by a regulator which I installed at the same time. (They recomend the water pressure to be between 1.7 and 5 Bar for this particular model). If I had more than 2 people drawing on it, I feel that I would require a larger model.

It regenerates automaticaly at night at 2 AM, in our case I think about twice a week but it's difficult to catch it "at it" so to speak so I'm guessing a little here based on the level of the salt tablets in the casing the next morning. The unit came with 15mm flex pipes but we purchased 22mm flex pipes to minimise pressure drop (manufacturers' reccommendation), however the pressure drops to 2.8 Bar when the shower is on. (All pressures measured on the inlet side just after the pressure regulator) the resistance to flow is therefore before the pressure regulator which comprises the following: Water meter, stop valve,

10Meters of pipe to main in road and external stop tap in the pavement. That sounds a bit garbled but I hope you get the jist.

I haven't measured the pressure drop across the unit but the spec says " for flow rate of 24 L/Min pressure drop =1Bar"

We fill the salt container approx once a week and it's very easy do do so.

Hope this Helps Come back to me if you stillhave a query, Ill do my best to find out but you may be able to get more detailed info from the maker/supplier. Best Regards

Don

[Nick Holmes]

Thanks very much Don. I wish we had your mains pressure.

when it says > "for flow rate of 24 L/Min pressure drop =1Bar"

I am struggling to follow the implications of this for flow rates.

I suppose all I care about is that, when plumbed in to the CW feed, my putative direct combi boiler can still deliver its max continuous HW flow rate (say 16l/min at 35c rise, e.g Avanta 39c).

I am well aware that a resin bed can apply very significant resistance to a system (25 years ago I used to run a high pressure chromatography system which could take >200 bar to drive 'water' at 0.006l/min through a 0.6 x 0.0046m (l x d) resin bed!

[Nick Holmes]

Whoops that should have read 20 bar. I did use 200 bar sometimes but that was with a hydrophobic resin so not a fair comparison.

I have changed the thread title in the hope of attracting wider comment on the issue.

[Donwill]

I think there is more info on pressure drop for different flow rates on the site, if you get enough points you my be able to join them together with asmooth curve and extrapolate from that,. try contacting manufacturer or distributor through the site link I refered to earlier, they may have a graph of pressure drop / flow rate.

Open a new thread , ( i.e Info required on water softener), you may attract more comment. Cheers Don