Suggestions for a new boiler/system please.

[luckyglen]

Hi,

Just moved into a new house about 6 months ago and now discovered that the shiny relatively new efficient combi boiler has got a big problem. It's a six year old 35Kw Veissman Vitodens 100 which has problems with the heat exchanger, the flow diverter and some of the internal plastic hoses are degrading. It's outside the warranty period and I'm thinking that if it breaks again I might need to replace it.

So the setup is as follows
250m2 detatched house
17 radiators
Combi boiler for DHW and CH
No power showers
2 bathrooms and a downstairs toilet.
Double glazed
300mm loft insulation

I'm considering a worcester or valliant boiler with a thermal store, and possibly solar thermal input. I've also toyed with the idea of an ASHP. Initial outlay is less of a problem, provided it pays long term.

Any advice would be gratefully appreciated.

 

[dcawkwell]

I would go for a glow worm ultrapower a cross between unvented
cylinder and combi. Will work as a combi if tank runs out and can
work as a combi if just a couple in the house.
Fast water delivery rates just like an unvented cylinder.
Measure your flow rate. Perhaps an accumulator tank required
if you want to drive two showers/baths at the same time.

 

[luckyglen]

I was informed that reliability of glow worm wasn't brilliant. Was that wrong?

 

[dcawkwell]

I was informed that reliability of glow worm wasn't brilliant. Was that wrong?

Glow worm and vaillant are virtually hand in hand. Same pcb control software, same pumps, same heat exchangers. All part of the same
group and they have the same training centres.
You pay a slight premium for the vaillants.

I've been installing the cheapest glow worm betacoms in rental properties
so far faultless reliability.

 

[luckyglen]

Also I thought combi's were cheaper to run than a boiler and a cylinder because you're paying to heat hot water all the time, rather than when you need it.

I should state I have no expertise in heating systems, just recycling what others have told me. I'm sure the question is much more complex than I'm thinking, can you elaborate why that system is better? Thanks.

 

[dcawkwell]

Also I thought combi's were cheaper to run than a boiler and a cylinder because you're paying to heat hot water all the time, rather than when you need it.

I should state I have no expertise in heating systems, just recycling what others have told me. I'm sure the question is much more complex than I'm thinking, can you elaborate why that system is better? Thanks.

This boiler can run as a plain combi 10-15 litres a minute or whatever it is
for economy. If there are more people in the house switch the tank on and it will deliver whatever the flow rate is into the house 20-30 litres a minute
until the tank is empty and the boiler can't keep up. It then swaps back
to combi mode delivering 10-15 litres a minute of hot water.
Best of both worlds for high demand households. It also has the advantage should the boiler fail for any reason you have immersion heater backup so no waiting for the repair man to get hot water back.
All in the one box.
Job sorted.

 

[luckyglen]

Thanks for that, the boiler's misbehaved again tonight, so I think I'll be changing sooner rather than later.

 

[5544]

Go for a vaillant. Yes gloworm are now part of the same group, but to say they are practically the same is a joke. Just look at the both of the side by side and you will see for yourself.

 

[ChrisR]

Until recently we had a comedy duo on here ranting about how Viessmann were the best thing since piped gas. Seems they've gone off to promote themselves and their products somewhere else - about time too!

Vail and GW do look somewhat same but different side by side. Though major components can be shared it's often the little parts like hoses and plastic manifolds which give trouble.

Most of the main makes are generally ok but all fail sometimes. Installation effort & carelessness, particularly regarding cleanliness & protection of the system water, can make a big difference.
Some of the less common makes/brands have looked great, until they start going wrong and you need a local or company repair person.

 

[luckyglen]

Does anyone think there's any point messing around with a thermal store then? Would solar thermal repay?

 

[dcawkwell]

Does anyone think there's any point messing around with a thermal store then? Would solar thermal repay?

No solar thermal waste of time.

You could integrate solar thermal at any time
by heating a feeder tank to preheat incoming mains water.
But solar thermal doesn't pay back.
At most the average household water heating costs are about £100 quid
or so.
Even some of the cheaper solar thermal kits excluding fitting are well
above £1000. Therefore it will never payback.

 

[ALEC1]

Viessmann do make exceptional products, the 35kw 222 for example provides 220 litres of hot water in the first 10 minutes, and then gives constant hot water at about 10l/m...

But its only really worth paying the premium price for this if you go for the weather compenstion kit that goes with it..

Not that others don't have weather comp they do...Gloworm have very user friendly controls...such as the clima pro...

 

[Phill Peck]

Just ready thru was about to suggest the same as Alec

Viessmann are a good boiler (although the earlier 100s did have some issues) and the 222 is very good you do need somewhere to put it though

The 242 would suit you if you are interested in solar


http://www.viessmann.co.uk/en/products/gas_fired_condensing/vitodens_242-f.html

 

[Phill Peck]

I should add although I understand why people ask these questions on here to get a wide view of opinion and options, but the best way to go about it is to research and find a product u want then find an installer who knows the product (manufacturers will provide you with details) or find a reputable installer and get their advise on what they would do in this situation.
Basically you need an installer that knows the product you will only get the best out of a system from someone who knows the boiler and controls