Combi boilers and water softeners

[sputnick]

I am looking to get a replacement boiler and thinking of changing to a combi.
All my existing water except drinking water goes through a water softener.
Both Baxi and Worcester say that I have to have the ch side connected to an unsoftened supply but can have to hot water side connected through the softener. How can I have both supplies if there is only one inlet.

 

[Diyisfun]

All my water goes through the softener (except drinking), with no problems, its been installed for about 8yrs & both softener & boiler have been serviced without any comments.

 

[JohnD]

How can I have both supplies if there is only one inlet.

There are two on a combi. The filling loop is only opened when you need to fill or top up the primary circuit (boiler and radiators). This does not mix with the tapwater.

I suppose, on the hopefully rare occasions when you need to top up the boiler/radiators, you could put the softener on "bypass" and run the taps to flush it through, before opening the filling loop under the boiler, or you could have the filling loop supplied from the unsoftened drinking water pipe, if you have one.

Opinions vary on the use of softened water. I use it, and Sentinel inhibitors, which Sentinel say are compatible with softened water. My boiler has a stainless steel heat exchanger; one of the reasons I chose it. It is not a combi. I would have been more cautious with Aluminium.

But opinions unsupported by evidence are not very valuable.

The only scientific test I have seen was sponsored by Harveys in 2012. Perhaps there are others that someone will provide.
link in here
http://hvpmag.co.uk/news/fullstory....uminium_heat_exchangers,_says_new_report.html

And their guarantee letter
https://www.harveywatersofteners.co.uk/downloads/aluminium_guarantee_letter.pdf

 

[sputnick]

Many thanks for your comments.

 

[Tom Mawson]

I have a water softener and noticed in many boiler instructions it says not to use softened water in the filling loop and also as a supply for the hot water.

After much research on the net it seems that its unlikely to affect the aluminium heat exchanger and as the boiler manufacturers havn't done much research on the subject they probably put it in there just to cover their arses.

I always put mine in bypass when filling up the central heating loop though.

 

[transam]

You would need to ask the specific boiler manufacturer , preferably in writing .If no mention of it is in there tech literature (?)

most or all manus are now giving extended warranties on there boilers 5 years plus (?) & some of them will be looking for any excuse in order to renage on any warranty claim down the line (?)

water quality is one such excuse that is often used (or will be) in order to renage on any warranty claim.

 

[muggles]

I am looking to get a replacement boiler and thinking of changing to a combi.
All my existing water except drinking water goes through a water softener.
Both Baxi and Worcester say that I have to have the ch side connected to an unsoftened supply but can have to hot water side connected through the softener. How can I have both supplies if there is only one inlet.

Fit an Intergas. Much better boiler than a Woofter and AFAIK (@Razor900 will confirm) there's no issue with filling the heating system with softened water. 10 year warranty on the ECO RF

 

[Razor900]

Softened water won't make any difference to an Intergas boiler

Not sure what it'll do to the rads though!

 

[Tom Mawson]

Not sure what it'll do to the rads though!

Eat them from the inside out.

 

[JohnD]

Eat them from the inside out.

How long will that take, do you think?

 

[Tom Mawson]

How long will that take, do you think?

Probably a very very long time, especially if you use inhibitor. I'm not sure if the inhibitor would counteract the corrosive properties of softened water anyway. But its not best practice and you don't want rusty coloured water and bits of rust flowing round your CH system

 

[JohnD]

So I've been lucky for 35 years then.

No sign of the rusty water yet.

 

[Agile]

For the Harvey I fitted a few weeks ago I arranged the fill water for the boiler to come from the unsoftened water.

I was thinking of the rads though and not the boiler as an Intergas is unlikely to be affected.

Tony

 

[Tom Mawson]

So I've been lucky for 35 years then.

No sign of the rusty water yet.

like I said, if you use inhibitor it probably counteracts it, especially if you the Sentinel stuff states its ok as you said above. But I don't understand why you would want to waste softened water and no just put the loop on bypass.

When I went on holiday this year I came back to a trickle of brown water out of the taps so I presume there is a steel fitting somewhere or its eating away at a ball valve maybe.

 

[Agile]

The total volume of a CH system is about 80 li. To fill that for a year might use 8 li at the most.

That is insignificant in water usage!