Replacing boiler, to combi or not to combi

[semrots]

Hi there, I'm sure this has come up before and I have trawled the forum but if you guys could help me with our specific issues please?

We're in a largish 4 bed house, with a bathroom (bath & shower) and an ensuite (shower ). There's 16 rads in the house. Currently we have a Thorn gravity fed boiler, the original still working OK (hope I'm not tempting fate!!) but around 30 odd years old. System is gravity fed, pump is in the boiler for heating only - no valves or associated wiring with the cylinder up in the airing cupboard to enable seprate heating/hot water.

We're looking at doing up the utility and moving the boiler would free up much needed space - we're looking at the garage, and thats convenient for picking up the gas supply and existing pipe runs to boiler.

We've had 4 guys round, 3 say go combi, the last, BG, say don't. Their advice being 'you'll only ever get one hot tap to work at a time', and pipe run from boiler to far side of house means long wait for water, and risk of leaking pipes.

Boilers suggested are Baxi Duo Tech 40kW, Worcester Bosch 37 CDi, BG 330+, and an Italian Combi one, forgotten make, at 38Kw.

So is a combi suitable for this installation, or not? Yes we understand there could be an issue with pipework and the pressure from the combi, and we are solid floored downstairs. Although one guy said combis often loose pressure and a pipe weeping in a solid floor is nothing to worry,and not too worry so long as you're only having to repressurise around once a week.

I suspect the combi would be an easier install, especially as an alternative means installing control valves on pipes near the cylinder and moving the pump there, and running the control cabling will mean a lot of floor boards up.

Lastly the Worcester guy says it is covered parts and labour for 6 years, is this usual or an 'added value' he's providing.

Any thoughts and advice on anything else we need to consider or ensure they are fitting/doing much appreciated.

 

[sambotc]

Sounds like you've had on the whole, some really bad advise.

Personally I would advise against a combi and agree with BG.

Firstly, long runs to hot taps cause delays in hot water and bowls of cold thrown away. Secondly topping up your heating system with water which has been lost through leaks is a quick way to cause corrosion related problems to your boiler and heating system. Any leaks need to be found and fixed. Pressurising your existing system is like roulette, could be lucky, could not.

A well designed and installed open vent system is just as good if not better IMO than a sealed system.

I would be advising a new condensing regular boiler fitted in the garage, all new controls, high recovery water cylinder, convert to S plan and system flush from the infomation you have provided.

There are a lot of installers who don't think twice about ripping a system out and plonking a combi on the wall, easy money. That isn't often the most suitable solution for the end user though. You have multiple bathrooms and siting the boiler far away from them.

I think if you are on the approved worcester installer scheme (forgot the official title) you can offer your customers a 5 year warranty when registered with worcester, not heard of 6 years myself.

HTH Sam