Softened water problems

[houstonceng]

My MES used to collect rain water to use on our fortnightly Public Running day’s throughout the summer. With so called “global warming” we had less and less rain during our running season. Having vacated our previous site, another story, we have less roof area to collect rainwater and now running every Sunday between April and October, we investigated water softening. Reverse osmosis wouldn’t be viable as we are not on mains drainage and with up to a 10:1 ratio between total water through the system to water softener, it would flood our site quickly. We had an ion exchange softener installed and all seemed well. The regeneration waste water has been piped into our chemical toilet - a maximum of 17 litres every 400 softened in very hard water areas.

Recently, a couple of members have had problems using the softened water. Priming, I can understand from previous postings about the Sodium salts that replace the Calcium and Magnesium in the hard water, however, one member reported that a brown deposit was found on the working parts of his loco’s safety valve.

We have contacted the manufacturers of the water softener who said they would look into it, but otherwise the softener was working as expected. Nothing back from them after three weeks.

Has anyone come across the brown deposit problem and/or any suggestions about reducing foaming in the boiler.

[flyingfox]

Greetings Andy, what you must do when preparing boiler water is to reduce the Total Dissolved Solids (TDS). Water softening does not reduce TDS. Rain water by its very nature has a low TDS, tap water varies across the UK, roughly the further east, or south you go, up goes the TDS. Great Yarmouth is the highest I think about 260 ppm. Electricity generating companies using steam boilers panic if their TDS goes over 0.5 ppm

If you want more detailed information about boiler water, get hold of an Model Engineer article "Water Water" I wrote about 10 to 13 years ago. Water softeners often use common salt, Sodium Chloride as their regenerator and Chloride ions in Copper boilers is real bad news.

Go back to rainwater some how.

Regards

Brian Baker

[houstonceng]

Brian. Thanks for the info. I will hunt for your article in my ME “archive”. I am aware of what you say here. What I was wondering was if there was any way of precipitating the Sodium salts (the majority of TDS in the softened water). Putting it through an RO system would not work for the same reason we cannot use RO directly on the hard water. In any case, if we could use RO, then we wouldn’t have invested in the ion-exchange unit. Basically, having told the water softener company our requirements, we were not sold the correct solution.

[steamer5]

Hi Andy,
How long have you had the water softener? Can you supply a link to the softener you have?
Do you make & store a heap of softened water for use over several days running, or do you make as required on the day? If you make on the day, do you make enough for the day or run the softener as required durning the day? Does the softener have any form of monitoring on it, or do you use any portable monitoring?
When you run the softener do you throw away the first, say couple of volume equivalents of the softener, water? Softeners by there nature will allow ions to be released into the water if left standing, potentially giving you even more dissolved ions than the incoming water.

Cheers Kerrin

[houstonceng]

We had it insayalled on25 May this year.
www.harveywatersofteners.co.uk/products/water-softeners/?_gl=1*2v7i8k*_up*MQ..&gclid=CjwKCAjwu4WoBhBkEiwAojNdXjwpLKEy9Z_ZmD_WldCkjmUIp_US89GzkJE39-YB2jkodClTWtZWNxoC2sUQAvD_BwE
We did store some softened water in outer water tower, but we now have a bypass direct to steaming bays and station area. The idea was to leave the tanks empty to collect the maximum volume of rainwater and, when that wasn’t available, use the softened mains water.
Per a domestic arrangement, water is taken from the softener at mains pressure as and when one of the taps is opened. We also run our water heaters in the loo and kitchen of the drivers’ Hut from it, but drinking water is unsoftened. A few members are worried about taking in extra sodium, even though it’s only two cups of tea each week.
No automatic monitoring. Just the occasional check on the salt blocks and a test of the water it’s a tablet.
Would be a bit difficult to throw away the first two volumes as the process is continuous and regeneration is automatic. Basically, there are two chambers. Effectively, water is supplied from both. When one needs regeneration, it is disconnected from the output and softened water is supplied from the second chamber. Once regenerated, the first chamber ones on line and both supply until the second needs regeneration, Then rinse and repeat.
I have noticed that members tend to open taps on the refill hoses and “waste” some onto the ground, to check flow before filling, so there is a little flushing, but not much.

[steamer5]

Hi Andy,
That’s a pretty nice unit! Reading thru there info it reads as you shouldn’t have issues for years! I didn’t find anything about needing to flush before use, & given its for home use I guess it doesn’t need it! The only proviso would be that it’s in daily use in a house, we’re as you guys only run it on the weekend? So maybe look at running to waste when you first startup, and hopefully after that should be ok for the day?
On the boiler priming front, not trying to teach grandma to suck eggs, blow the boiler down at the end of the day. My preference is drop the fire & to allow the pressure to reduce down to about 30psi & then blow down to empty. Increased TDS is a cause of priming, & as it sounds like your water is hard so swapping hard salt for soft still means hi mineral content, & the boiler is good at concentrating that up! As to the brown deposit not so sure! Maybe another mineral maybe iron or manganese but that only a guess, you would need to get a water analyse done. If the water you are using comes from a council supply they may have an analysis already.

It will be interesting to see what the softener company comes back with.

Cheers Kerrin

[chris vine]

To me, the biggest question is whether sodium ions are bad for our boilers. Probably a different answer for steel and copper.
For stainless steel, very common in superheaters, I would think that sodium ions at high temperature might be a real problem.

One would really need either a metallurgist with knowledge of this area. Or, a group of model engineers who have tried it for a considerable time to have found out the effects or lack of them.

For myself I have a totally different solution:
I keep the water from the workshop and engine shed dehumidifiers. I have plenty of drums to store it from the winter, and seem to have enough to last through the summer running.

My original plan was to use the water butt which collects water from the workshop roof. However there is a large plum tree overhead and the fallen fruit make the "rain" water smell like rank (plum) cider. Not any use for boilers!

Chris.

[millman]

I have a dehumidifier running in the workshop and like Chris I collect the water during the winter for use in the following running season, however I have been told that dehumidifier water is bad for the boilers, I don’t understand why because as far as I can work out it is only moisture in the air, same as rain is, isn’t it. Can someone on the forum please tell us all what water is good and what is bad for our boilers. The club I belong to is planning to fit a reverse osmosis system this winter, one of our members apparently “knows” about such things and says this water will be ideal for us and save members humping large plastic containers of water to the track every time they run, but apparently the reverse osmosis unit needs the water passed through a water softener first. Fortunately owning a caravan we took the van down to Devon early in the season and on the day we were returning home I filled up both our roll along water containers with 45 litres each of lovely soft West Country water, nearly done myself an injury though lifting them up to waist height to put them in the back of the Land Rover but sadly I have now used it all.

[chris vine]

Interesting!
At the kent and East Sussex railway, they are very proactive in their water supply and have reverse osmosis plant.
However I understand that the water supplied is not at all good for steel boilers without additives.
More info/understanding needed maybe
C 🚂🚂🚂