New CH boiler

kristoff101

Looking to change our 20 year old boiler for a new one but I am getting conflicting recommendations.

Its a 4 bed 2 bathroom home with 14 radiators.

One recommendation is for a 37kw combi and the other was that combi boilers are suitable for small properties only so I am confused.

Any recommendations from people who have upgraded from a conventional system (with stored hot water) would be gratefully received.

Also if anyone has any advice on which type to avoid that would equally be appreciated.

Thanks

silps

I'm about to do the same thing as you but we are going to stick to having an open vented system with hot water cylinder. The main reason being with a sealed system as in a combi it is pressurised and if our oldish pipes leak it would be a pain to find the leak and fix if under the ground floor. Also, if you have 2 bathrooms and use hot water around the house at the same time a combi might not cope.

ziggyman99

If you intend to use both bathrooms at the same time then the combi may not be the best choice. Some people have 1 bath and 1 shower room with an electric shower. That works well and also gives you a backup if the boiler breaks down. Do you need the space were the hot water cylinder is? If not then it may be better to stay with a heat only boiler.
How did the installer arrive at a 37kW boiler? Did he measure the flow rate at the cold tap? If you have very good flow rates and pressure, an alternative is a storage combi. That would give suberb hot water flow rates and allow both bathrooms to be used at once. A great example, which I have fitted myself, is the Vaillant 937. I was very pleased with the output, as was the customer. It is a huge boiler though and won't look right hanging in a kitchen! More suitable for a loft or airing cupboard.

kristoff101

Thanks for the replies. Ziggyman - Thanks for the heads up on the Vaillant, I like the sound of the spec and have found a price online for £1295 inc vat. I am going to get a price for a local installer to fit.

garethgas

Personally, I would steer clear of the combi route. They have their place but if you want decent hot water on tap (sorry) then I would stick with stored hot water. Even the largest combi's can't match what you already have.
There are lots of negatives regarding combi's but all too often installers will try and steer you towards one because its in their interests to do so not yours.
My advice would be to search for a good installer as most problems stem from poor installation, even 5 yrs down the line.

Canucklehead

Good morning: it makes no difference to my OH whether he installs a combi, regular or system boiler. It boggles the mind why folks think the conversion of an open vented to a sealed system is the easier or more convenient option for an experienced RGI.

An unvented cylinder with a system boiler is recommended for a 2 bathroom property if you have sufficient water mains pressure and flow rates. A RGi, after conducting a site survey and discussing your requirements, would be best placed to advise.

HTH

Canucklehead