Water related problems and why I installed RO (Paul L)

Izzo Alex MK-II: Water-related problems and why I moved to RO

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Some background
In a short space of time I had some problems with my Alex which were all linked to the same cause. It led to me having to learn how to undertake two repairs and one consequential check (for which a repair would follow the same procedure). The whole episode was a real eye-opener and flowed (sorry – pun intended) from an incredibly important but mostly over-looked aspect of your home coffee making so let’s start there. It’s called water.

I suspect many home users are doing exactly what I did. Using jug filters in the knowledge that limescale problems are an enemy of the coffee machine. Thankfully jug filters are available cheaply and we all know that these 'wonder products' significantly reduce the hardness of tap water and help to avoid water related problems. Right?

Well, I learned the hard way (another pun intended!) and personally I no longer rely on jug filters based on bitter experience.

Water problems take time to show themselves though and so it’s hard to know whether the quality of water we put into our machines really matters and, if it does, what do we mean by quality?

My solution was to do what I suspect many others do:

  • I descaled my coffee machine at least every 6 months
  • I used a jug with replaceable filters which I replaced monthly
  • It was suggested to me this may not be enough so I started changing the filters weekly.

Despite this, it became apparent that this was not enough when I had to:

  • clean and restore proper operation of the anti-backflow otherwise known as a non-return valve
  • Clean and replace a sticking vacuum breaker
  • Remove scale build up from inside the brew boiler (an eye opener)
  • Install RO as a preventative measure going forward (a necessity for me)

The importance of water
Let me throw some figures at you which may or may not be accurate but will give you a basic framework (contaminants in water is measured in TDS and whilst this does not correlate directly to the water hardness and amount of limescale it appears to share a close relationship):

  • In Europe the maximum permitted TDS by water companies is 500 ppm (parts per million)
  • In the UK the maximum permitted TDS by water companies is 400 ppm (parts per million)
  • If you look at a water hardness map of the UK much of the mainland sees water hardness of 300 ppm or greater
  • If you suffer this hardness of water then as limescale builds up over time the TDS in your coffee machine can also build up. One home user measured this over 600 ppm before installing an RO system
  • Various figures are quoted as the ideal TDS of water going into our machines and none seem to suggest using above 50 to 60 ppm. Crikey, that’s a bit different from our tap water then
  • In fact, water is so sensitive an issue that damage to equipment caused by water is typically an exclusion from product warranties if you take a look. This can be the case for coffee machines, water machines and vending machines
  • You really need to think about that last one. If you have to return equipment back to your supplier for warranty repair and want to tell them about the quality or reliability of either the machine they have sold you or certain components that are failing you need to consider if you are in fact causing the problem. It could be the case that the cause is not covered by warranty and that your vendor has the right to charge you for investigation, repair, replacement and so on.
  • In the commercial world down-time inevitably means lost revenue and therefore expensive in-line water filtration systems will be deployed costing perhaps hundreds of pounds and requiring periodic filter replacement approaching perhaps £100 per replacement.

Now, we may be unlikely to submit our domestic coffee machines to commercial use or volumes of water throughput but we need to ask ourselves if it makes sense that we only need tiny jug filters yet commercial water filtration is on a totally different scale?

That depends on how effective a jug filter is, naturally. When we relax because we start using a jug filter we don’t question this as a consumer, the marketing of the filters tells us our water will be better (or at least I think it does because I did not pay close attention, I made an assumption). Perhaps we then change the filter maybe once a month, maybe less frequently or maybe more often if we are dedicated. We assume all is okay but we don’t really know what is going on. In my case, this approach led to the following in the space of a few months:

Problem no.1 - anti-backflow valve

Separate article here)

Problem no.2 - the vacuum breaker
The existing Wiki articles will explain this component. My Alex developed the issue of false boiler pressure when switched on each morning. I would come back to it half an hour later, feel a lukewarm grouphead, blast the steam wand, watch the pressure drop to virtually zero and then it would recover and be fine for the rest of the day.

Sorting out the water supply cured the sticking problems and I have had no repeat problems after some 3 months to date.

Problem no.3 - limescale inside the boiler


I purchased a 30mm/32mm box spanner from eBay in order to undo the element which was a useful thing to have to learn as elements need replacing from time to time. Careful re-assembly using PTFE tape went absolutely fine.

boiler_002.jpg boiler_003.jpg

Now, having taken the element out to look inside a couple of days after a descale was a surprise as I did not expect to see that limescale sitting in the bottom of the boiler. So, this picture is simply to show you what may be going on inside your own coffee machine despite your best current efforts relying on descaling.

Solution - RO installation


I had to reduce the hardness of the water supply being fed into my machine. You need to understand the water supply in your own area to see if this would be appropriate for you.

An under-sink RO system does not have to be inconvenient, large or difficult in operation. This has a small footprint, requires no separate water tank or pump, provides a water pressure of about 2.6 bar and is very easy to use in practise. The blue pipe is the RO water pipe, the green is the bypass for the run-off containing the filtered contaminants and the red pipe is the inlet from the mains. Each individual pipe has closure valves for added safety from leaks.

It takes me about 14 minutes to produce 1 litre of RO water and so it is easy to work this into a weekly routine when you work out your consumption. In my case, probably about 90 minutes every 2 or 3 days. It really isn't that much to ask. Total cost of the system was less than £100 including the plumbing extras, TDS handheld meter, pressure gauge etc.

A quick summary of the TDS:
• TDS of my tap water = 300 ppm (give or take from day to day)
• TDS of a new jug filter if used for less than a week = 140 ppm (my lowest measurement on filters used for less than 1 week, TDS only gets worse form there)
• TDS from my RO pipe = 8 to 10 ppm (depending on water pressure at the time)
• TDS exiting the grouphead = 19 ppm (at last count some 3 months since installation, I check about once a month)

Pure RO or not

There is some question on whether pure RO is so low in TDS that it can be aggressive to the inside of your coffee machine. I have not seen it proven either way and I would imagine it depends on the construction of your machine as well. Nevertheless, many people raise the TDS of their water by adding a percentage of non-filtered (or at least non RO) water back into the mix aiming for TDs of perhaps 50 ppm.

Tank_001.jpg Tank_002.jpg

A 'dual-water' version of the Alex can run off of either the internal water tank (2.3 L capacity) or an external supply (any size you like). Thankfully mine is this version and this is a fantastic option that I did not use for the first year of ownership until now. To be honest I thought it would mean a complicated set-up but I now know that it is not.

Look at the pictures and you will see:

  • a 5L bottle of water typically found in superstores very cheaply (in this case 79p or for non-UK readers 0.79 GBP)
  • the braided pipe supplied with the dual-water version which is easy to fit to the Alex (check for leaks though)
  • the other end loosely in the bottle with no problem. I retained the lid and made a hole in it so that the open surface area was smaller than without the lid (my anti-wasp/fly approach!)

This has the benefit of:

  • no more removal of the Alex cover or risk of spilling water inside the machine when filling (even though the Alex chassis is mad eof stainless steel throughout)
  • no more sliding the 25kg+ Alex around to fill the internal tank
  • nice large capacity for less frequent filling
  • makes life easy by being able to see the water supply.

It is one of those things I wish I had done earlier.

Addition Summer 2008: I very quickly settled into a new water routine by using two of these 5L containers. With one in use I wait until it's about half-way or less and then I fill the second with 4L of RO water into it and 1L of spring water.

  • If you do the maths you have (4L x 10 ppm) + (1L x 85 ppm) = so about 25 ppm give or take
  • it means you have your next bottle ready to swap out allowing you to dry/sterilise the removed one
  • once you have a couple of these bottles you don't need to buy them again even if you want the RO/spring water mix as I do as I have found that superstores also stock 4 x 2L bottles for the same price per litre
  • once you are set up and then buying 2L bottles most your spring water stock remains unopened
  • If you are reading this outside of the UK then note that spring water is a boutique market over here. The superstore own-branded Scottish water I am describing is about 0.16 GBP per litre so 4 x 2L costs about GBP 1.28 or thereabouts. A trendy 0.5L bottle of water with a sports cap can often cost close to that in our stores and fuel service stations and at least double in restaurants.

This whole episode was aimed at preserving the operation and cleanliness of the machine. However, there has been another less obvious benefit. Alex owners use a fair bit of water with cooling flushes and any machine owner uses a fair bit of water with general and cleaning routines. My water set-up means no running short of water and using water is not an irritation to the point that if water usage or cooling flush is reason for aspiring to a dual-boiler machine then it becomes less of an issue.