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I was 'drifting' the 'Temporary Outside Tap' thread too much with my questions about accumulators so I though I'd start a new one (but I don't know how to link to that existing thread - soz).

 

The flow from my 3/8th" main is 15lts/min at 4bar which wise counsel advises me is a bit puny and the advice was 1 or 2 accumulators situated outside of the house to give me the boost I need. I've agonised over where to put the accumulator/s and am now thinking of going ahead without using an accumulator initially and then retro-fitting one when it becomes obvious it's required.

 

After the house is built we will apply for planning for a garage (we've been advised to wait that long) which would be a suitable location for the accumulator/s so the question is, how would I go about having the plumbing done with the ability to add an accumulator with ease at a later date that will be situated in  a garage that as yet doesn't exist - mind you, neither does the house yet1

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Quite simple. Just T out of the cold main AFTER the softener and run a large bore ( 32mm ) MDPE out to where the garage / acc’r may end up. Just cap that off and leave it for later. 

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@Nickfromwales thanks. I was hoping the words would be something along the lines of ‘quite simple’. 

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16 hours ago, Nickfromwales said:

Quite simple. Just T out of the cold main AFTER the softener and run a large bore ( 32mm ) MDPE out to where the garage / acc’r may end up. Just cap that off and leave it for later. 

 

 

Be very wary of fitting the accumulator after the softener if you are looking to use a Harvey or similar twin cylinder softener.  They do not like having a slightly higher pressure on the outlet than the inlet and will reward you for doing this by filling your plumbing with salty water every now and again (ask me how I know this...).  I had to re-plumb our system so the in-house 100 litre accumulator was on the inlet side of the water softener to fix this problem, as my initial fix of fitting a non-return valve on the softener outlet didn't work, probably because the high outlet pressure is still "seen" by the internal valve system within the softener that changes over from one cylinder to another during regen. 

 

If using a single cylinder softener then make sure there is a non-return valve on the outlet (single cylinder units usually have one, or specify that one is fitted).

 

You also need a double non-return valve on the incoming supply, before the accumulator, so that the accumulator doesn't back feed the main when/if the incoming pressure drops.  Normally there will be one of these on the incoming water main, next to the water meter or external stop cock, but older systems may not have one.

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I wondered before but in light of @JSHarris's post I'm going to ask, why @Nickfromwales specify (so emphatically) that the accumulator tee should be after the softener? Is it just a case of not having hard water clog up the accumulator eventually or is there something more subtle? Puzzles me as I'd think the cold water in the accumulator wouldn't be much of a problem for that.

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There's no limescale problem from having hard water in the accumulator that I'm aware of.  Pretty much every domestic borehole supply in a hard water area will have an accumulator just after the pump, and before any water treatment system. 

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Does the softener act as a restrictor in some way? Would that be why @Nickfromwales suggests the accumulator is downstream from it?

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1 hour ago, Russdl said:

Does the softener act as a restrictor in some way? Would that be why @Nickfromwales suggests the accumulator is downstream from it?

 

Depends on the softener, but all will cause a small pressure drop, although not enough to make any significant difference if the supply pressure is high enough.

 

All I know for sure (from personal experience) is that the twin cylinder softeners (like the Harvey, but these come with several different badges on) do not like having a slightly higher pressure on their outlet than their inlet.  It disrupts the way the internal water pressure operated valves work when they change over and can cause salty water to get into the house plumbing.  It happened with our system a couple of times, when I had an accumulator on the outlet side of the softener.  The first time it happened I flushed all the pipework out and fitted a non-return valve on the softener outlet, but it happened again, so I shifted the accumulator over to the inlet side and it has never happened since.

 

There's also the problem with running an unsoftened supply to the kitchen tap if you fit an accumulator after the softener.  There's a recommendation that if you fit an ion exchange water softener you should run an unsoftened supply to the main potable water tap, due to concerns over excessive sodium intake.  I, personally, don't 100% agree with this, as there is little evidence that the small increase in sodium intake from drinking ion exchange softened water is potentially harmful.  In our case, the amount of sodium in the softened water is pretty small, and only makes up a tiny fraction of the recommended daily intake.  It's also a lower than the level that's allowable in a drinking water supply.

 

I think the key thing is really being aware that there is slightly more sodium in softened water and, if you're concerned about it, take steps to reduce your sodium intake from other food and drink to compensate.  In our case, my daily sodium intake is around half the maximum recommended, so the little bit that comes from drinking softened water doesn't cause me any concern.

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Just to be awkward......

 

I am of the opposite opinion where I would routinely have the accumulator on the output side of the softener. 

 

I would fit a robust double check non return valve on the output side and have the accumulator full of softened water to guarantee high flow, softened, water can service at least two showers at any one time without suffering any noticeable pressure drop ( subject to the run times being suited to the design capacity of the accumulator ). 

 

Re the hard water outlet at the kitchen sink. If you have a boiling water tap then the remit is usually to feed it with softened water as per the MI’s. I suppose it’s down to the water quality after your chosen softener spits it out ?

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How do you solve the softener valve problem though, Nick?  I tried a check valve between the softener and the accumulator and it didn't solve the problem, I had to move the accumulator to the inlet side to fix it. 

 

Probably not a problem with a single cylinder, non-metered, type softener, that regens overnight when there's no water demand, but my experience suggests it is definitely a problem for the non-electric twin cylinder type softeners.

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@Nickfromwales & @JSHarris thanks for both of your input on this, and the contrary positions makes for interesting debate. 

 

We plan to have the boiling water tap, one of which we have seen combines everything including filtered drinking water (which seems a bit, er, wet as good old tap water has seen me through this far) but as a supplementary question, would the water filter remove the sodium from the softener?

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43 minutes ago, Russdl said:

We plan to have the boiling water tap, one of which we have seen combines everything including filtered drinking water (which seems a bit, er, wet as good old tap water has seen me through this far) but as a supplementary question, would the water filter remove the sodium from the softener?

 

No, you can't filter sodium ions out of water with the sort of activated carbon and phosphate dosing cartridge that's normally supplied with boiling water taps.  You can remove the sodium ions by more expensive (and lower flow rate) systems, but it's not worth the hassle, IMHO. 

 

To put the sodium content of softened water into context, it's worth looking at how significant it is in terms of the amount of water you drink.  An ion exchange softener exchanges calcium for sodium in a ratio of 2.17:1, so if you had water that was really hard, say 400mg/litre calcium equivalent, then there would be 184mg/litre of sodium in the softened water.

 

So, every litre of softened water you consumed would give you an intake of 184mg of sodium.  A litre of milk contains about 400 to 600mg of sodium.  The recommended maximum daily intake of sodium is currently 3400mg for an adult, although I monitor my sodium intake reasonably closely and rarely exceed around 2000mg per day - I think you have to have a pretty unhealthy diet to get over the recommended 3400mg daily intake, although it's surprising just how much hidden sodium there is in some foods.

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@JSHarris well that answered that question pretty comprehensively!

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