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https://www.askthetrades.co.uk/cgi-bin/yabb/YaBB.pl DIY Forum >> Plumbing Questions >> External boiler; anti freeze https://www.askthetrades.co.uk/cgi-bin/yabb/YaBB.pl?num=1429376534 Message started by woodsmith on Apr 18^th, 2015, 6:02pm

Title: External boiler; anti freeze
Post by woodsmith on Apr 18^th, 2015, 6:02pm

Should a heating system have anti freeze added if you have an external boiler, bearing in mind the boiler is fitted with a frost stat?

Thanks.

Title: Re: External boiler; anti freeze
Post by thescruff on Apr 18^th, 2015, 10:21pm

What does the manual say, I would say no as antifreeze is corrosive without inhibitors at the right blend

Title: Re: External boiler; anti freeze
Post by woodsmith on Apr 18^th, 2015, 10:57pm

Thanks, the heating engineer wants to use Fernox Alphi 11 which has its own inhibitors but he's quoted £72 to add 5 litres so not cheap. I haven't seen any mention in the manual, I'll have another scan through to see if I've missed it.

Title: Re: External boiler; anti freeze
Post by thescruff on Apr 19^th, 2015, 7:10am

Quickly before I dash off to the Crucible.

Its a good product and maybe worth considering if you get extreams of cold, But, 5 ltrs will be a waste of time.

We used a similar procuct for the heat pumps and the minimum was 25% solution and that hasn't changed, therefore depending on the size of the system 25ltrs + would be required, Check out the fernox website there's some good info.

Buy your own and put it in after the guy has tested and gone.

https://www.plumbnation.co.uk/site/fernox-alphi-11-protector---25-litre/

Title: Re: External boiler; anti freeze
Post by woodsmith on Apr 19^th, 2015, 8:54am

Thanks, I hope you had a good night out.

I was the ref 11am to 11pm got back home 01:00 Zzzzzzzzzz

Title: Re: External boiler; anti freeze
Post by londonman on Apr 19^th, 2015, 9:51am

Keith, I've never bothered with anti-freeze in our external boiler. Never even entered my head since the boiler will be on if the weather is cold. Glad you went with one in the end! Makes a lot of sense. Which make?

Title: Re: External boiler; anti freeze
Post by woodsmith on Apr 19^th, 2015, 1:45pm

The quote I've got is for a Worcester Bosch 18/25 combi. Thought about getting a system boiler and having a mains pressure cylinder, but the logistics and costs didn't stack up. I had a boiler specialist round a few months ago when I was trying to get Listed Building consent and he recommended the W/B as has the heating engineer I plan to use to install it.

It will be good to get it out of the house, not a great idea having the boiler under the stairs next to the bedrooms.

Title: Re: External boiler; anti freeze
Post by londonman on May 6^th, 2015, 10:29pm

Interesting as when I was researching a while back WB said none of their boilers could go outside!

Title: Re: External boiler; anti freeze
Post by woodsmith on May 7^th, 2015, 8:33am

That's odd because they make a range of external boilers? Still haven't got mine, the engineer should have come last week but didn't turn up and not been in contact since! I'd fit the boiler myself if I was allowed.

Title: Re: External boiler; anti freeze
Post by londonman on May 8^th, 2015, 9:32am

You can. I did. Then got a bloke to come in to commission it and connect up the oil pipe. Needless to say that this 'qualified' person failed to position all the stopcocks, fire-valves etc at the required distances. The crucial thing was the bit of paper ...which TBH now I'm not sure where I put it. :-[