Should I ditch conventional system for a new storage combi?

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I'm hoping someone can lead me in the right direction before I waste an engineers time quoting for a central heating system that I might not go for.

Property Details
I have a largish 1800sq ft 4 bed house with bathroom and separate shower room, downstairs cloakroom, gas cooker, utility room with "modernish" cold feed appliances.

CH System
I have a conventional central heating system with tanks in the loft, airing cupboard with copper cyclinder, floor mounted 25kw Thorn EMI boiler all about 20 years old.

Problem
The boiler is working fine and it's not gone wrong so far, but it looks an eyesore and the tanks in the loft make lots of noise filling (wakes the family up), I suspect the cyclinder is heavily scaled as we live in a hard water area and the whole system is probably very inefficient. Also, we're planning to do some kitchen refurbishment so this is the ideal time for a replacement.

In truth, I like the idea of swapping to a sealed system with condensing combi boiler because we mainly shower and share baths and could make use of the extra airing cupboard and loft space, but is this really a good idea and am I being realistic? Do people normally do this sort of thing?

My main concern is that I spend £3k on a new installation and it doesn't do the job (in terms of delivering enough hot water). Partly, my concerns are based on experience - my aunt had a combi fitted 15 years ago and regretted it. However, I wonder if that's no longer a concern with the modern combi and some of the new storage combis?

I've read about the Vaillant ecoTec plus 937 and Alpha do a similar storage boiler. Also, I've heard that the Worcester Greenstar 37/42CDI is very good.

Can anyone give me some advice to get me on track? Thanks in advance.
 
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First you must realise that in answering your question, the trolls will be out in force and the thread will get locked again.

Making an old system sealed, can lead to problems with the existing pipework etc because of the higher pressure.

No modern boiler is that reliable unless you go for the top end market, Broag, Atmos, Viesmann, down the list a bit Alpha give an 5 year warranttee which is worth considering.

Combi's you have feed back from the Aunt, they are worse now than they were 15 years ago, so you must draw your own conclusions at the end of the day.

Dare I say it, but I would go for a good system boiler as above and do away with the tanks in the roof, then get an un-vented cylinder installed.

What is the mains pressure and Ltrs/min
 
Thanks for your reply doitall.

I quite like the idea of a system boiler. Form what I understand, this would appear to offer me the best of both worlds (removing the nosiy tanks in the loft and freeing space, whilst also ensuring the hot water supply).

I don't think our water pressure is very good. It was tested about 2 years ago, by the corgi engineer who last serviced our boiler (sorry I don't have the pressure figures, but he said it was towards the minimum requirement that had to be supplied). I've just tried to measure it from the kitchen sink and it filled two bowls in a minute (about 16 litres) - it's ok to use on a daily basis and we have an electric pump on the shower, so maybe that's a clue. Does that change/reinforce anything on your previous recommendation?

Also, can you give me any advice on the un-vented cylinders, in terms of problems in fitting them? Can I assume that it would be situated in the airing cupboard and a direct replacement for the old copper cylinder?
 
i would be a sort of direct replacement but with your 16 l/m its not going to perform well...you really need minimum 20 l/m and 2.5 - 3bar
 
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Thanks for your reply JPC.

Thats a shame! So, with the lower water pressure, I assume that rules out the combi too. Would you recommend that I just stick with the conventional system instead? Maybe just a boiler replacement?
 
Have you got a cellar. attached garage or utility room etc where you could put the kit
 
Yes, the floor mounted boiler is situated in our utility room, which we plan to rip out as part of the kitchen refurb works. It is failry big (600 deep * 450 wide * 900 high)

We're not fussed about hiding the boiler in a kitchen unit, but I was thinking that it might be nice to have a wall mounted one instead, so that we could use the space below - but it's not essential!
 
If you had the space you could have fitted the cylinder and the boiler in the utility room, and add an accumulator to boost the cold to the cylinder, problem is the accumulator is nearly as big as the cylinder.

On a side note you wouldn't be able to use the shower pump with an pressurized system.

Your budget may be out as well :LOL:
 
...the tanks in the loft make lots of noise filling (wakes the family up)... .

£5 on a new float valve (ballcock) will sort that. I use a Torbeck quiet valve, but not everyone likes them.

I am occasionally amazed that people sometimes put up with noisy tanks for years when they are so easy to cure.

I am not a plumber
 
if your happy with the performance of the existing system then stick with it
...new boiler and controls and job done. spend some money in the loft and have a new ball vlave or similar...insulate the tank well and the loft floor and you should not hear anything
 
also consider a new cylinder...if yours is old a new one should be better insulated and go for a fast recovery one.
 
Thanks doitall & JohnD.

The utility is not that big, so I guess that rules out the accumulator. I wouldn't be too worried about losing the shower pump, but it's a good point and something I hadn't thought about! I am concious of budget too - £3k is about our limit at the moment with the planned kitchen refurb.

Good point about the noisy tanks John, I should really treat them as a separate issue, but I'll get them looked at the same time as install regardless of the system type that I choose. (Also been dreaming about a loft conversion - so the tanks are in the back of my mind for that reason too).
 
If you go for a good system boiler, you can sort the cylinder tank problem at a later date
 

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