Water softeners and combi boilers

[abc123]

Hi all

Firstly I'm not a plumber or heating engineer so excuse my ignorance if this is a silly question.

I have a Potterton Gold 28 HE combi boiler. I live in a very hard water area and am thinking of getting a water softener installed in my home. I rang Potterton who said they didn't recommend this as the high salt content the softeners use will damage the boiler and reduce the life of it?

Is this true? I can't believe no one with a combi cannot have a water softener? None of the water softener companies I have spoken to have even asked what CH system I have, so they don't seem to think its a problem.

Will it damage my boiler or are there other methods I can use to treat the hard water we have?

Any thoughts or advice would be great
many thanks

 

[Plumbstar Tom]

Hi

Never fitted one to a combi but have a look here

Will your water softener work with a combi boiler? - Additional Text - Harvey Softeners

I would assume on this basis that if you fit one of theirs you will be ok

I did hear that they damage condesing boilers though but have no way of confirming this

 

[abc123]

Hi

Never fitted one to a combi but have a look here

Will your water softener work with a combi boiler? - Additional Text - Harvey Softeners

I would assume on this basis that if you fit one of theirs you will be ok

I did hear that they damage condesing boilers though but have no way of confirming this

Thanks mate. I just rang a local CH company and they said it depends on what type of heat exchange the boiler has, steel or aluminum. If steel its ok but not if aluminum, apparently the Potterton is aluminum (doh). I guess I can't have one then.

 

[Bernie2]

I was also going to say only if its a steel heat exchanger.

 

[abc123]

I was also going to say only if its a steel heat exchanger.

Damn. So what will it actually do to the boiler if we had one installed? The company who are coming around reckon it can be used on combi boilers

I was also going to say only if its a steel heat exchanger.

Just had a thought. What happens if combi boilers are installed in areas that already have soft water? Does that also mean their life expectancy is reduced?

 

[Bernie2]

Its said to be the base exchange chemicals contained in the softened water that cause the problem not naturally soft water.

Going a bit further, I have read that there are water softeners that you can use on aluminium heat exchanger boilers. But I rather fancy the boiler makers would have told you that if they where suitable for their boiler.

The thing is although you may void any guarantees on the boiler from the boiler makers, do the water softener people guarantee it won't harm the boiler and give you a guarantee it won't?

That way, its just a case of swapping guarantees. But I rather fancy they may not.

If the contractor says its okay, do they guarantee it and is it a bonded guarantee in case in a year or two they go broke you can still claim under the guarantee? And check any guarantees are transferable for any HIPS packs.

 

[abc123]

Its said to be the base exchange chemicals contained in the softened water that cause the problem not naturally soft water.

Going a bit further, I have read that there are water softeners that you can use on aluminium heat exchanger boilers. But I rather fancy the boiler makers would have told you that if they where suitable for their boiler.

The thing is although you may void any guarantees on the boiler from the boiler makers, do the water softener people guarantee it won't harm the boiler and give you a guarantee it won't?

That way, its just a case of swapping guarantees. But I rather fancy they may not.

If the contractor says its okay, do they guarantee it and is it a bonded guarantee in case in a year or two they go broke you can still claim under the guarantee? And check any guarantees are transferable for any HIPS packs.

My boiler isn't covered under a warranty anymore, a bloke from the water softening place is popping over next week so I will ask him about it, although their website says its fine for combis.

My thoughts are that without a softener my boiler will more than likely have problems in the future due to hard water, so it could be worth risking it. I have had the heat exchanger cleaned out once and we do suffer with intermittent banging noises which a BG engineer said was kettling due to build up in the system.

Not sure what to do for the best.

 

[Bernie2]

Yes I agree it's a pretty tough call. I would wait and see what the softener guy says. Its a bit rich really for boiler manufacturers to be selling combi boilers that can't have softened water running through the DHW.

Its not as though hard water is a new problem. Nor are base exchange softeners. So its a mystery why they did not know people may want to put softened water through them and advise against fitting aluminium heat exchangers in hard water areas.

But as you say there are so many different opinions out there its hard to decide what to do.

The problem is a new boiler costs a bomb and if you don't soften the water it will fur up and if you do soften the water it may attack the heat exchanger.

On balance unless the softener guy says its okay, then I would look at it from two angles.

If the heat exchanger goes because its been attacked by the softened water, it may mean new parts every so often. How long that would be I don't know, it depends how aggressive the water is.

But if you leave the water as it is, you'll get a build up, unless you regularly defur it with chemical washes.

Which ever way you look at it, its a lot of messing about for you.

Good fortune

 

[abc123]

Yes I agree it's a pretty tough call. I would wait and see what the softener guy says. Its a bit rich really for boiler manufacturers to be selling combi boilers that can't have softened water running through the DHW.

Its not as though hard water is a new problem. Nor are base exchange softeners. So its a mystery why they did not know people may want to put softened water through them and advise against fitting aluminium heat exchangers in hard water areas.

But as you say there are so many different opinions out there its hard to decide what to do.

The problem is a new boiler costs a bomb and if you don't soften the water it will fur up and if you do soften the water it may attack the heat exchanger.

On balance unless the softener guy says its okay, then I would look at it from two angles.

If the heat exchanger goes because its been attacked by the softened water, it may mean new parts every so often. How long that would be I don't know, it depends how aggressive the water is.

But if you leave the water as it is, you'll get a build up, unless you regularly defur it with chemical washes.

Which ever way you look at it, its a lot of messing about for you.

Good fortune

Thanks. I managed to get another company around and they said that there's no problem with combis and softeners and even though they keep hearing this advice about aluminum heat exchangers there is no evidence that it does any damage? I must admit I cannot find any definitive proof on the internet that exchangers are being damaged. The cynic in me thinks the boiler companies don't want you to have clean heat exchangers because they make money replacing them !!!

Is it possible to exchange an aluminum heat exchanger for a steel one? if not and the exchanger goes because of soft water are they expensive to replace?

 

[Bernie2]

Hi!abc123!

To renew the heat exchanger in a Potterton Gold HE 28 GCN 47 393 19 means removing the gas valve, which is part of the gas train so it can only usually be done by Gas Safe registered people.

The thing is, as far as I can find the Potterton Gold HE 28 Gas Council Number 47.393.19 has a stainless steel heat exchanger not an aluminium one.

In which case you should ask your local Water company which is the best softener for your area.

Basically Potterton say the same in their boiler manual. So if they say it in the Potterton manual your boiler should be okay, with an approved water softener on the DHW and a inhibitor in the system side.

Unless of course Potterton are saying to you on the phone not to fit a softener for some other reason than the heat exchanger.

Good Fortune

 

[abc123]

Hi!abc123!

To renew the heat exchanger in a Potterton Gold HE 28 GCN 47 393 19 means removing the gas valve, which is part of the gas train so it can only usually be done by Gas Safe registered people.

The thing is, as far as I can find the Potterton Gold HE 28 Gas Council Number 47.393.19 has a stainless steel heat exchanger not an aluminium one.

In which case you should ask your local Water company which is the best softener for your area.

Basically Potterton say the same in their boiler manual. So if they say it in the Potterton manual your boiler should be okay, with an approved water softener on the DHW and a inhibitor in the system side.

Unless of course Potterton are saying to you on the phone not to fit a softener for some other reason than the heat exchanger.

Good Fortune

What a star, thanks Bernie2. I just assumed the advice I was given was accurate, but your right the Potterton website says "Features the very latest stainless steel heat exchanger technology"

Looks like I should be ok afterall as long as use the correct inhibitor, woo hoo !!!

 

[Kayball]

I know this is a bit late, but I offer my experience with an ion exchange (salt regeneration type) softner and aluminium. Whilst not heat exchanger related it is offered as a caution. I have an aluminium egg poacher which is used daily. I always use softened hot water from the kitchen tap, as no contact with food is made and, using unsoftened water previously, lime scale formed very quickly in the pan.
Using softened water has certaily stopped any scale forming, but the base of the pan is now very pitted and, in my opinion, is being attacked by the boiling softened water. If this is evident after 6 months in an item which is only used for 6 minutes, five days a week, then a heat exchanger would be perforated quite quickly. I hope this experience is usefull. Incidentaly, my boiler is a Vaillant ecoTech 418 which has a stainless steel heat exchanger.

 

[Bernie2]

If you have hard water you have a Low Ph if you soften it, it makes for a more acidic higher Ph.

So being more acidic it attacks metals.

The Ph table is 14 with 7 being that of pure water. So if you soften the water to the extent its higher than say Ph 8.5 you can have corrosion pitting problems which is what seems to be happening to the bottom of your pan.

That is why its probably best to ask your water supplier about the best sort of softener to use and its dosage rate. After all they know what is in their own water probably better than anybody else. A local water softener guy is probably just as good.

In my area we have what is known as soft water and yes it does pit aluminium pans. Thought at one time to be a part cause of Alzheimer's disease. But it doesn't seem to affect the boilers much. Although being frank I don't think anybody has collected any local data about it either that I know of.

Perhaps there should be a national register of suitable boilers for each area?

 

[H2Ooh]

Hi!abc123!

To renew the heat exchanger in a Potterton Gold HE 28 GCN 47 393 19 means removing the gas valve, which is part of the gas train so it can only usually be done by Gas Safe registered people.

The thing is, as far as I can find the Potterton Gold HE 28 Gas Council Number 47.393.19 has a stainless steel heat exchanger not an aluminium one.

In which case you should ask your local Water company which is the best softener for your area.

Basically Potterton say the same in their boiler manual. So if they say it in the Potterton manual your boiler should be okay, with an approved water softener on the DHW and a inhibitor in the system side.

Unless of course Potterton are saying to you on the phone not to fit a softener for some other reason than the heat exchanger.

Good Fortune

Not sure if this info will be useful to anyone wondering. I work with a water softener company and this has been quite a contentious issue for many customers.

I have spoken with 5 boiler manufacturers regarding the matter, including Vaillant, Ariston, Viessmann, Ferroli and Potterton (Baxi Group). None of them said that using a water softener would affect the warranty as long it functioned properly. 4/5 actually recommended using a water softener.

The issue of steel vs aluminum heat exchangers is also shrouded in a bit of mystery. Noone has ever shown any plumbers at Harvey's an aluminum heat exchanger that had been wrecked by soft water and most boiler manufacturers don't even differentiate when recommending whether it is wise to use one.

I will keep any postings here free from bias or advertising rubbish but I will say that the guarantee still depends on the water softener functioning correctly so it is always wise to opt for a high quality model.

 

[ggaylmer]

Well late into this discussion!
Just reading about aluminium corrosion. Aluminium is prone to corrosion when an electrolyte solution such as salt is present and the aluminium is connected to another metal such as steel or copper, or even fastened with rivets or screws of a different metal. It is called Galvanic corrosion. This is a problem in sea vessels which require a special grade of aluminium and other precautions and protection, such as a "sacrificial anode". This is where a metal that is more reactive than aluminium, is attached to it and is preferentially corroded by electrolysis, while at the same time protecting the aluminium. This technique is I believe used in combination hot water storage cylinders, where the sacrificial anode is found in the reservoir tank above, to protect the copper from corrosion.
So if the heat exchangers are aluminium and they are fastened to other metal structures in the boiler, they could corrode when salt is present in the water. Of course the amount of salt getting into the supply is supposed to be fairly low when using water softeners, but over time could be a problem. I have read a post where a plumber said he learned about this the hard way when a boiler he fitted failed and started leaking after 6 months due to a water softener. Another post where a customer's boiler failed and the exchanger leaked after only 2 years.

 

[Reg Man]

I can see where the boiler manufacturer is coming from if you fill the central heating side with water softener water, but if you pipe it up correctly you can top up fill the central heating with untreated water. can't see that there's any problem running treated water through the plate heat exchanger.

In any event there should only be minimal amount of salt residue. Its not the salt that softens the water. The salt is present after regeneration of the water softener. ie: the salt cleans the hardness from the resin in the softener every 2-3 days usually at night time.

 

[michael c]

in hard water areas i have been fitting inline limescale reducers just before the boiler or a small electrical device which puts a small electrical pulse through the water (cant think of the name of it though sorry i will try). Whats peoples thoughts on these methods as only really been fitting for last year so not had much feedback as of yet