Water softener to fit under sink

[Chris S]

Good evening,

 

I'm trying to find a suitable water softener that will fit under a kitchen sink.

 

The kitchen isn't installed yet so I can't take measurements, but I think I have about 460 to 480mm height available. Plenty of width available and about 550mm depth within the cabinet.

 

There are 5 of us (2 adults plus 3 young kids), with just the one bathroom and a WC. We have a combi boiler and supply pressure of around 2 bar. Total hardness according to water supplier is 350 mg/l (very hard).

 

Would prefer a proper softener rather than a salt free one but realise they may be the way forward.

 

I'm having a hard time getting past all the marketing waffle and finding proper product data, hence I'm turning to you guys for help!

 

Any recommendations??

 

Thank you

[Jeremy Harris]

A Harvey, or similar, will fit in a kitchen cabinet OK.  I can measure ours tomorrow, but I'm sure it will fit OK.

[Gone West]

10 hours ago, Chris S said:

Any recommendations??

We have a Harveys Crown which is 490mm high and 460mm deep. The box is 210mm wide but with the pipe connections ours is 270mm wide.

[Chris S]

Thank you guys. Yes, I like the size of the Harvey and the pipe connection locations are great. Just got to consider the incredibly high price tag now! I haven't asked for a quote or demo yet (wanted to be clued up first) but see they can be bought for around £850 ish from other suppliers.

 

I've also realised that I can cut a hole in the base of the kitchen unit so the softener can sit on the floor. That does open up some other options.

[Bitpipe]

Would recommend one that takes blocks vs loose salt / pellets (I have the latter) as it's a faff to fill and you need to lug about 25kg bags and inevitably get spills etc.

[Jeremy Harris]

I'd second getting one with blocks.  We have a Harvey that uses block salt and it's pretty clean and easy to handle.  You can also store packs of blocks a bit more easily, as each refill is separately packaged.

[JoeLondon]

On 02/09/2019 at 21:31, Chris S said:

Good evening,

 

I'm trying to find a suitable water softener that will fit under a kitchen sink.

 

The kitchen isn't installed yet so I can't take measurements, but I think I have about 460 to 480mm height available. Plenty of width available and about 550mm depth within the cabinet.

 

There are 5 of us (2 adults plus 3 young kids), with just the one bathroom and a WC. We have a combi boiler and supply pressure of around 2 bar. Total hardness according to water supplier is 350 mg/l (very hard).

 

Would prefer a proper softener rather than a salt free one but realise they may be the way forward.

 

I'm having a hard time getting past all the marketing waffle and finding proper product data, hence I'm turning to you guys for help!

 

Any recommendations??

 

Thank you

 

The Harvey is excellent. We have one installed underneath our kitchen sink. When you consider the dimensions, make sure you leave some rooms for taking the salt block compartment lid off for refilling. If you don't buy directly from Harvey, make sure you get a well qualified plumber to fix it. Apparently there are some tricks to set up the precise flow-rate for column/filter regeneration. 

 

[Gone West]

2 hours ago, JoeLondon said:

If you don't buy directly from Harvey, make sure you get a well qualified plumber to fix it.

I've owned a few different block salt softeners over the years and always installed them myself. I've never had problems with regeneration, as the supplier has set the hardness value, so I'd be interested to know what the setting up tricks are.

[Jeremy Harris]

There is no way to adjust a Harvey for different water hardness once it is in-situ.  The water meter inside the top cover is set during manufacture for a particular hardness range and this cannot be changed.  I've had our spare one apart, and all there is in the water meter is an impeller plus a lot of gears, nothing in there is adjustable.  I would guess that Harvey have a range of different gears they can install during manufacture in order to change the preset hardness, as the top cover is labelled with the hardness range that the unit is set for.

[NSS]

5 hours ago, JSHarris said:

There is no way to adjust a Harvey for different water hardness once it is in-situ.  The water meter inside the top cover is set during manufacture for a particular hardness range and this cannot be changed.  I've had our spare one apart, and all there is in the water meter is an impeller plus a lot of gears, nothing in there is adjustable.  I would guess that Harvey have a range of different gears they can install during manufacture in order to change the preset hardness, as the top cover is labelled with the hardness range that the unit is set for.

We have a Twintec which I thought to be pretty much identical to the Harvey, but ours can certainly be adjusted for degree of water hardness (and indeed was by our installer).

[Jeremy Harris]

8 hours ago, NSS said:

We have a Twintec which I thought to be pretty much identical to the Harvey, but ours can certainly be adjusted for degree of water hardness (and indeed was by our installer).

 

 

Interestingly, the spare one I took apart has a Twintec label on the case, but a standard Harvey unit inside.  Where is the adjustment for hardness, out of interest?  Maybe there is more than one type of water metering unit fitted to these units.

[NSS]

47 minutes ago, JSHarris said:

 

 

Interestingly, the spare one I took apart has a Twintec label on the case, but a standard Harvey unit inside.  Where is the adjustment for hardness, out of interest?  Maybe there is more than one type of water metering unit fitted to these units.

Not sure, but the installer definitely checked the hardness and then adjusted the unit to suit. I believe it was something to do with the volume between regenerations.

[Jeremy Harris]

1 minute ago, NSS said:

Not sure, but the installer definitely checked the hardness and then adjusted the unit to suit. I believe it was something to do with the volume between regenerations.

 

 

That's true, it is the volume between regenerations, but it can only be set by changing the water metering assembly, something that I've tried (out of curiosity) and found to be very challenging, as all the gears fall out when you lift the cover off!

 

Here's a photo of the front of our spare TwinTec (with the top lid off):

 

 

And here's a photo of the top of the water meter assembly, with the label showing that this unit is preset at the factory to regenerate every 750 litres (looks like there are four different water meter gearbox options):

 

 

 

[Chris S]

Wow, lots of detailed responses, thank you. I wonder if Harvey and Twintec merged? I noticed that Monarch's non-electric softener goes by a different name too.

 

The next question is what price should I expect to be quoted by Harvey and what should I realistically be able to get them down to? I haven't contacted them yet I as want to be clued up with alternative options in order to get a good deal (!). I'd prefer to install myself as I'm fitting the kitchen and plumbing.

 

Thanks

[dpmiller]

The Kinetico units are a bit different, there's a clear cover ontop of the meterhead that you can easily unscrew to swap out a little metering disc underneath.

[PeterW]

You can get them on eBay refurbished from £350 upward. 

[Gone West]

1 hour ago, JSHarris said:

Interestingly, the spare one I took apart has a Twintec label on the case, but a standard Harvey unit inside.

Harveys make the TwinTec as well as the MiniMax and Crown.

[tommyt]

I spent a good few years installing and servicing all kinds of domestic water softeners. All the Harvey's made units can only be ordered in four different settings depending on water hardness as indicated by the model numbers on the pic above. The model numbers refer to the number of litres of treated water that will pass the metering system before a regeneration is triggered. Four settings to cover any incoming water hardness means it it may not be running at full resin efficiency. Kinetico comes in 8 settings IIRC and can be more easily adjusted by changing the metering disc in the top although still fiddly and can be further adjusted on the brine height setting allowing harnesses at the edge of a range. They are both fairly reliable units though in my experience. Most faults were with stones or blue polythene pipe burrs blocking internal passageways.

A lot of the cheaper 10-15 Litre basic electrically operated water softeners found in builders merchants are actually a lot more efficient in terms of exchange capacity as they can be set to an exact litre figure and tested and adjusted easily by the customer after installation if not quite right. I used to always recommend anything with a Fleck or Autotrol control valve on top. Maybe slightly less reliable but the initial purchase price saving and salt running costs (The electrical costs are miniscule plus potential waste water savings if set up correctly) will easily pay for future maintenance and if you are handy plenty of Youtube guides showing how to strip and rebuild them. Plus spare available online.

 

[Jeremy Harris]

8 hours ago, tommyt said:

I spent a good few years installing and servicing all kinds of domestic water softeners. All the Harvey's made units can only be ordered in four different settings depending on water hardness as indicated by the model numbers on the pic above. The model numbers refer to the number of litres of treated water that will pass the metering system before a regeneration is triggered. Four settings to cover any incoming water hardness means it it may not be running at full resin efficiency. Kinetico comes in 8 settings IIRC and can be more easily adjusted by changing the metering disc in the top although still fiddly and can be further adjusted on the brine height setting allowing harnesses at the edge of a range. They are both fairly reliable units though in my experience. Most faults were with stones or blue polythene pipe burrs blocking internal passageways.

A lot of the cheaper 10-15 Litre basic electrically operated water softeners found in builders merchants are actually a lot more efficient in terms of exchange capacity as they can be set to an exact litre figure and tested and adjusted easily by the customer after installation if not quite right. I used to always recommend anything with a Fleck or Autotrol control valve on top. Maybe slightly less reliable but the initial purchase price saving and salt running costs (The electrical costs are miniscule plus potential waste water savings if set up correctly) will easily pay for future maintenance and if you are handy plenty of Youtube guides showing how to strip and rebuild them. Plus spare available online.

 

 

 

Not sure this is technically correct, TBH. 

 

There's not really any such thing as "resin efficiency", the ion exchange process is pretty simple and as long as there are enough sodium ions present on the resin they will be exchanged for calcium ions in the water.  All ion exchange softeners are identical in terms of how efficiently the ion exchange process works (assuming the tanks are correctly sized for the flow rate), as it's just pretty simple, very well understood, chemistry (well, technically, not really chemistry).

 

The only two factors that relate in some way to efficiency are how much water is wasted during the regeneration process (some machines can waste a great deal more water than others) and how much salt solution is wasted during regeneration (again, some can waste a great deal more than others).

 

The key factor regarding both salt and water wastage, over and above the amount of salt (or more specifically sodium ions) required to regenerate the ion exchange resin, is set by the "hardness" adjustments on some units, although technically these setting make absolutely no difference to the water coming from the unit at all (as long as they are set conservatively, to provide a slight excess of sodium ion capacity remaining on the resin at regeneration time).  What the settings do is either adjust how much water passes through the resin tank before regeneration starts, or how much time has passed since the last regeneration in the case of electric timer models.  Clearly the latter has the potential to be inherently more wasteful of both water and salt solution, as a timer has no way of knowing how much water has passed through the unit, and hence how depleted of sodium ions the resin has become.

 

It makes sense to use softeners with water metering, as a general point, as in the majority of cases they will always waste less water and salt solution.  When it comes to metering setting then it gets more complicated, as, although the Harvey meter only has four sets of gear trains that can be selected when the unit is built (these set the volume of water used per tank before regeneration starts), the Havey meter is a great deal more sensitive at low flow rates than the Kinetico one, so meters much more accurately in general.  Kinetico have double the number of settings in their water meter gearing primarily to overcome the inability of their water meter design to measure low flow rates (typically the sort of low flow when wash basins are used at a trickle).

 

Whether there is much practical difference between the water and salt solution wastage between either the Harvey or Kinetico units will depend almost entirely on how any measurement schedule is devised.  I've no doubt that Harvey use a test and measurement cycle that is biased towards showing up the improved sensitivity of their water meter, but whether this is realistic for any household is going to depend very much on how that compares to the actual pattern of use.

 

The bottom line is that all ion exchange water softeners can soften equally well, and all water softeners will waste water and salt solution.  All timer-based ion exchange softeners are likely to be much more wasteful at times than water meter type softeners^[1].  I strongly suspect that any difference in wastage between softeners like the Harvey and Kinetico are more likely to be influenced by differences in water usage pattern than they are by the design of the water meters they use. 

 

 

 

 

^[1]  As an example as to why this is, take our water filtration (uses a water softener type electric timer valve to operate the backwash and flush system).  This is set to backwash the filter bed once every 4 days, at 2.00am.  This is generally fine, but we were away for three days over Christmas, so the unit would have wasted about 75% of the backwash and flush water, as it doesn't actually measure how much water has passed through the filter bed, so doesn't know whether or not it really needs a backwash and flush.  A timer controlled softener will similarly be very wasteful under the same circumstances, it will just flush loads of unused salt solution down the drain.

[tommyt]

If you are not using resin to its maximum capacity before regenerating it is not efficient.  Nearly all domestic size softeners are fairly inefficient due to the setting methods. And as you say some models are even less efficient by wasting excess water and salt to regenerate. There is no disputing the accuracy of the Harveys metering system as they are fitted with Kent meters , the same as the water board fit in your house so you know they aren't missing a drop. Each of the four available Harveys models can only be using 100% exchange capacity at one incoming hardness value. If your water harness is actually below this value the softener is not being efficient and is regenerating more often than needed. (thus wasting salt and water) and they would certainly err on the side of caution when specifying your model needed. 

With the cheaper single column softener models the inefficiency comes from the fact that most cannot provide softened water whilst regenerating, so are set to do so at periods of low usage (night time in most domestic situations) and as such are programmed with a Safety factor or Reserve capacity meaning they run at say 80-90% efficiency most of the time and have the extra 10-20% in reserve to last until the machine can be regenerated.  So if the softener manufacturer recommends a setting of say 1000litres at 300ppm hardness it will probably actually soften up to 1200 litres before becoming exhausted.

Also you are correct about the metering accuracy of some of the cheaper models which can often not read very low flows normally caused by large storage tanks and ballcock filling valves where if the tank level only drops a small amount when say flushing a toilet or washing hands the the ballcock will not fully open and has very low flow at the beginning and end of its stroke. Softeners are then set to regenerate more often to combat this thus then being less efficient. 

The best way to have full exchange efficiency is to use a Duplex machine with a digital programmer capable of incremental settings so as soon as a column reaches maximum exchange capacity it swaps duty to the other column and regenerates to exhausted one. But these are normally larger machines not suited for under sink installation. 

 

 

 

 

[Jeremy Harris]

27 minutes ago, tommyt said:

If you are not using resin to its maximum capacity before regenerating it is not efficient.  Nearly all domestic size softeners are fairly inefficient due to the setting methods. And as you say some models are even less efficient by wasting excess water and salt to regenerate. There is no disputing the accuracy of the Harveys metering system as they are fitted with Kent meters , the same as the water board fit in your house so you know they aren't missing a drop. Each of the four available Harveys models can only be using 100% exchange capacity at one incoming hardness value. If your water harness is actually below this value the softener is not being efficient and is regenerating more often than needed. (thus wasting salt and water) and they would certainly err on the side of caution when specifying your model needed. 

With the cheaper single column softener models the inefficiency comes from the fact that most cannot provide softened water whilst regenerating, so are set to do so at periods of low usage (night time in most domestic situations) and as such are programmed with a Safety factor or Reserve capacity meaning they run at say 80-90% efficiency most of the time and have the extra 10-20% in reserve to last until the machine can be regenerated.  So if the softener manufacturer recommends a setting of say 1000litres at 300ppm hardness it will probably actually soften up to 1200 litres before becoming exhausted.

Also you are correct about the metering accuracy of some of the cheaper models which can often not read very low flows normally caused by large storage tanks and ballcock filling valves where if the tank level only drops a small amount when say flushing a toilet or washing hands the the ballcock will not fully open and has very low flow at the beginning and end of its stroke. Softeners are then set to regenerate more often to combat this thus then being less efficient. 

The best way to have full exchange efficiency is to use a Duplex machine with a digital programmer capable of incremental settings so as soon as a column reaches maximum exchange capacity it swaps duty to the other column and regenerates to exhausted one. But these are normally larger machines not suited for under sink installation. 

 

 

 

 

 

 

I think we're mixing up measures of efficiency here.  Ion exchange resin doesn't behave any differently, to any significant (or measurable) degree between being fully "charged" with sodium ions and being almost depleted of sodium ions, with most available binding sites occupied by calcium ions.  The softener will work just as well, as long as there are still enough sodium ions available to be preferentially exchanged with incoming calcium ions - the softening efficiency doesn't change to any measurable degree.

 

The only two measures of efficiency that are possible (for a non-electric softener) are:

 

1.  How much water does the unit waste as a proportion of the water that it treats?

 

2.  How much salt solution does the unit waste as a proportion of the sodium ion exchange per cycle?

 

All ion exchange softeners waste water and waste salt solution, because all, without exception, use an excess of salt solution during regeneration in order to ensure that all available binding sites are occupied with sodium ions.

 

There are other arguments relating to aspects that aren't related to efficiency, like twin tank units being able to provide softened water 24/7, 365 days a year, because they do not have to interrupt the flow of softened water during regeneration, as well as aspects like the tiny amount of electricity that an electric unit will use to run the timer unit.

 

Clearly using a metered softener (of any type) that is set to regenerate too frequently for the local water hardness is inefficient, yet such units are always set to err a bit on the side of caution, to ensure that the sodium ion content of the resin doesn't become fully depleted before regeneration starts, as that would lead to non-softened water being delivered towards the end of each cycle. 

 

In some areas, though, there is also a marked variation in water hardness with the season.  Where we used to live the hardness would increase significantly in mid-summer, when more of the mains supply was being drawn from the deep chalk aquifer, and decrease by as much as 50 to 80 mg/l CaCO₃ equivalent in winter, when the supply came from alternative sources.  Any softener regeneration volume setting would have to be set for the summer hardness level, with the user accepting the poorer efficiency (more wasted water and salt solution) in winter.  Our borehole supply is always the same hardness all year around, because we're drawing from a fairly deep greensand aquifer, that is replenished very slowly (hundreds of years, rather than tens of years) from chalk ground water, held above a gault aquatard, that percolates very slowly down into the greensand.  It was exactly the same when I measured it a few weeks ago as it was when we drilled the borehole back in 2013, which at leaks made setting up our softener simple and allows it to run more efficiently (less wasted water and salt solution).

 

 

[tommyt]

I just don't think using something at 75% of its capacity is efficient.  Having only four settings/models for all conceivable water hardness values across a range means it can only be right four times. For all other hardness values it is almost right. That just doesn't work for me. If you can get one of their units cheap then go for it but the retail prices on their own brand are eye watering compared to a trade spec alternative from a merchant which can give a finer range of adjustment. Both if setup correctly will give fully softened water at the outlet. Which is all most customers want. And efficiency is less of a concern. I was always surprised how many people would go for a more expensive machine with a plastic cover over the top controls because it looked nicer and then have it installed in their under sink cupboard next to a stinky food waste bin.

 

5 hours ago, Jeremy Harris said:

 

All ion exchange softeners waste water and waste salt solution, because all, without exception, use an excess of salt solution during regeneration in order to ensure that all available binding sites are occupied with sodium ions.

 

 Now this isn't strictly true. If the resin needs that volume of salt and water to be considered fully recharged then it isn't an excess as such.  It is exactly the right amount that is needed. Upflow brining units can reduce 

 

Regenerating the resin before it is fully exhausted and using salt and water unnecessarily is less efficient than running it to capacity and then regenerating is.

You wont find many industrial units that aren't Duplex, Triplex or more and that aren't run to maximum capacity before regenerating but these are more closely monitored than a domestic machine would be. Water tests can be conducted by operatives daily and adjustments made accordingly. Some units have electronic chemical testing units testing the product water every minute and triggering a regeneration the moment the mineral content rises above a set point. 

 

[Jeremy Harris]

1 minute ago, tommyt said:

I just don't think using something at 75% of its capacity is efficient.  Having only four settings/models for all conceivable water hardness values across a range means it can only be right four times. For all other hardness values it is almost right. That just doesn't work for me. If you can get one of their units cheap then go for it but the retail prices on their own brand are eye watering compared to a trade spec alternative from a merchant which can give a finer range of adjustment. Both if setup correctly will give fully softened water at the outlet. Which is all most customers want. And efficiency is less of a concern. I was always surprised how many people would go for a more expensive machine with a plastic cover over the top controls because it looked nicer and then have it installed in their under sink cupboard next to a stinky food waste bin.

 

 

 

 

As earlier, we need to define efficient.  Does it cost more if only 75% of the possible binding sites are regularly used, for example?  Not really.  If anything, it probably extends the resin usable life before exhaustion, so may well be cheaper, and so arguably more efficient.

 

Efficiency is the wrong term for defining convenience properties of any device, as by definition, in this case, it relates to the amount of waste generated (salt solution wasted plus water wasted) relative to the amount of treated water delivered.

 

 

1 minute ago, tommyt said:

 

 Now this isn't strictly true. If the resin needs that volume of salt and water to be considered fully recharged then it isn't an excess as such.  It is exactly the right amount that is needed. Upflow brining units can reduce 

 

Regenerating the resin before it is fully exhausted and using salt and water unnecessarily is less efficient than running it to capacity and then regenerating is.

 

 

It's absolutely true.   As a former chemist, who used ion exchange columns in the lab, then I can vouch for the fact that any ion exchange medium has a defined number of binding sites for a given volume of media.  No commercial water softener ever runs until all the binding sites have zero sodium ions, for several reasons:

 

1. Any practical mechanism for controlling regeneration has no way of knowing how many binding sites have already exchanged their sodium ions for calcium ions at any given time (or volume) since the column was last regenerated, so any timing/metering system can only make a very approximate estimate at the remaining capacity.

 

2.  Any metering system will have some inaccuracy, largely associated with the dynamic flow range that it needs to operate over, plus an inherent tolerance on any initial calibration.  Even a domestic water meter, as used for billing, is only accurate to about 2% in the upper band and may be as much as 5% out in the lower band.  Metering systems fitted to metered softeners are unlikely to be more accurate than this, and may well be significantly less accurate at low flow rates.

 

3.  Water hardness varies from time to time, often seasonally in some areas, so the setting used before either timed or volumetric regeneration sequencing has to be based on the worst case, that for the hardest water likely to be experienced in that area.

 

4.  There has to be a sensible initial allowance for the reduction in ion binding sites with time, both because of the fairly slow chemical degradation of all ion exchange resins, and because of the slow mechanical changes within the resin bed that reduce the available number of binding sites with time.

 

The net result is that all ion exchange water softeners will be initially set up so that they use more salt solution during regeneration than might be assumed by the absolute ion exchange ratio of ~0.46.  If any ion exchange softener was initially set up so that it regenerated when exactly 100% of the initial ion exchange media binding sites had been depleted, then it would start to deliver unsoftened water before long, due to all the variables given above.  The sensible thing for all manufacturers to do is err on the side of caution, and ensure that any unit is initially set up to ensure that there will still be enough working binding sites available close the end of the units working life (or life before ion exchange resin replacement).

 

This always means that some salt solution will be wasted, as will some flush water.  The question is whether this variation in wastage/efficiency between different brands is significant.  Clearly any metered unit is more likely to be more efficient than any timed unit, but whether some metered units are significantly more efficient (in terms of generating less waste per unit softened water) than others is debatable, and, as mentioned earlier, highly dependent on usage pattern within the household, as that has far and away the most significant impact of metering accuracy.

 

 

1 minute ago, tommyt said:

 

You wont find many industrial units that aren't Duplex, Triplex or more and that aren't run to maximum capacity before regenerating but these are more closely monitored than a domestic machine would be. Water tests can be conducted by operatives daily and adjustments made accordingly. Some units have electronic chemical testing units testing the product water every minute and triggering a regeneration the moment the mineral content rises above a set point. 

 

Agreed, but I've never seen a domestic unit that has any form of reliable, process control, type monitoring and control system in order to reduce both salt solution usage and water wastage.  I recall seeing one unit years ago with a supposed hardness meter fitted to the outlet, but in reality it was a simple conductivity (a.k.a. TDS) meter, which was about as much use as a chocolate fireguard, given that its electrodes were permanently in the outlet flow.

 

[tommyt]

Not many time clock models on the market these days (although most digital metered programmers allow the facility to set this) . In my experience though a metered machine will nearly always regenerate at a set pattern of days such as a time clock model would because a modern families daily water usage is fairly constant throughout the week and the softeners are set at a maximum of one daily regeneration.  Gone are the days when all the clothes washing or even family baths were done on one particular day of the week! So you could say that any other claimed benefits of a particular softener over a straight forward time clock machine are just marketing gimmicks.