Soft Water Central Heating

Adam75 · 5 Apr 2020

Hi,

Is it ok to fill a sealed central heating system with softened water?

I installed a Harveys water softener a month ago. Today I replaced 2 radiators where I needed to drain the system.

Using softened water in a combi boiler for hot water now seems ok to do so. The advice has changed over the years.

After searching the net, it seems using softener in central heating systems is not recommended as this may cause pin prick leaks overtime. But again advice is quite mixed.

I filled my CH wit softener water today but it has only just occurred to me this might not be wise. Should I drain and fill again with hard water?

thanks
Adam

JohnD · 5 Apr 2020

There are lots of opinions about this but, so far as I know, only one scientific test, which was carried out by the BSI, and you can look up the report.

http://www.ukwta.org/assets/NewFolder/BSi-Corrosion-Report-12.12.12.pdf

Most opinions are not based on scientific research, but on prejudice.

sxturbo · 5 Apr 2020

Things have changed in recent times.

I am no expert on such things however but Germany latest standards no longer use inhibitors.

My installer is going to fill my system with softened water (he fills all his systems this way)

I believe you need to make sure the pH balance is correct,

I'm not 100% sure on all the ins and outs of it.

Unfortunately the chaps whom are most likely to know about this no longer frequent because of some know it all members whom aren't actually heating engineers

Mottie · 5 Apr 2020

sxturbo said:
I believe you need to make sure the pH balance is correct,

That’s what I did with mine. https://www.diynot.com/diy/threads/system-ph-question.537489/

muggles · 6 Apr 2020

sxturbo said:
My installer is going to fill my system with softened water (he fills all his systems this way)

I believe you need to make sure the pH balance is correct,

I suspect (hope) they're going to used demineralised water rather than softened, although the demin filter does also have some softening effect. VDI2035 standards used in Germany and some other countries do indeed promote demineralised water and pH balancing, and whilst it is a superior method of filling a system for a variety of reasons, it is not without its challenges. You can't top up your own heating system unless a demin filter is in place, for example, and UK boiler manufacturers do not yet officially recognize this system of water treatment so it may affect the boiler's warranty.

sxturbo · 6 Apr 2020

muggles said:
I suspect (hope) they're going to used demineralised water rather than softened, although the demin filter does also have some softening effect. VDI2035 standards used in Germany and some other countries do indeed promote demineralised water and pH balancing, and whilst it is a superior method of filling a system for a variety of reasons, it is not without its challenges. You can't top up your own heating system unless a demin filter is in place, for example, and UK boiler manufacturers do not yet officially recognize this system of water treatment so it may affect the boiler's warranty.

Intergas accept it officially and honour the warranty for the boiler. The installer is also a well respected pro on here recommended to me by Dan Robinson (he is a member on here also but i think he sticks to the trades part of the forum).

he hasn't finished it yet, COVID kind of stopped play, he managed to get it to a point i have heating and i am running hot water from the immersion, he is yet to fill it with softened water.

but i trust him completely and am sure it will all be fine when the restrictions get lifted.

My only concern is should i have to top up the system for any reason, but will just mean i'll have to get him out to do so.

Adam75 · 6 Apr 2020

Thanks sxturbo. What you have done is far too complicated for me. I just need to decide whether to leave the softened water in my CH or drain and refill with HW. From JohnD's post it sounds like having softened water is not a problem

Gasguru · 6 Apr 2020

If you take a look at the German heating forums (and google translate) you'll find it's pure myth that their systems are problem free...they have sludge and corrosion just like us.
Don't get confused over softened water...running through the domestic side may not be an issue but it can void the warranty if filling the system side.

sxturbo · 6 Apr 2020

Adam75 said:
Thanks sxturbo. What you have done is far too complicated for me. I just need to decide whether to leave the softened water in my CH or drain and refill with HW. From JohnD's post it sounds like having softened water is not a problem

softened water is fine,

i was answering a post from another forum member.

you should however also check the Ph balance of the water, to acidic or to much alkaline can both be detrimental.

in the report posted by John D an aerator should also be installed in the system, for optimum reliability.

Gasguru · 6 Apr 2020

Your Intergas has copper waterways on both the system and domestic side.
Most boilers have aluminium or stainless on the system side and stainless on the domestic side.
I'd be checking the manual and warranty conditions...
One of the concerns is the brine/salts content.

JohnD · 6 Apr 2020

Softened water from a water softener does not contain salt or brine.

It does however contain a tiny amount of soluble sodium bicarbonate, as found in indigestion remedies and baking powder.

Gasguru · 6 Apr 2020

The contamination of the water is an argument that will run and run....ultimately manufacturers warranty condition trumps opinion on a forum.

JohnD · 6 Apr 2020

If the manufacturer has scientific evidence to support their opinion, no doubt they will be able to prove that their contractual terms are reasonable.

If not, not.

P.s.
I did not write the BSI report and it is not an "opinion on a forum"

sxturbo · 6 Apr 2020

Gasguru said:
Your Intergas has copper waterways on both the system and domestic side.
Most boilers have aluminium or stainless on the system side and stainless on the domestic side.
I'd be checking the manual and warranty conditions...
One of the concerns is the brine/salts content.

the installer is an intergas platinum installer. Intergas will honour warranties installed according to the german specification. Precedent is set as the same boilers are sold in germany with no modifications nor reduced warranty periods. The installer advised me he hs discussions with intergas regarding this, and all his boilers are installed via this method and have been for a number of years.

He said he can do it with tap water and inhibitor if i prefer, however he is the professional and its his workmanship i am employing, i am not going to question his professionalism. That's why i'm paying him.

if it were to all go belly up there's always the courts etc to claim back, and i don't believe any professional installer would put their business on the line unless they were sure of having complete and full back up.

flameport · 7 Apr 2020

What do people who live in soft water areas like South Wales fill their heating systems with?

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Soft Water Central Heating

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