Which central heating system

[rustydonkey]

I have a 1930’s semi with 3 bedrooms a and a large loft conversion. It has solid walls (bonded) and is quite hard to keep warm as I cant have cavity wall insulation put in. At the moment it has a 12 year old Worcester Bosch combi heating the house and hot water. 3 months ago it completely broke and they had to come out 3 times in one week to fix it leaving me with no hot water. The boiler is now not heating the water up fully so I rung Worcester Bosch and told them of the problem to which they said it will cost £210 to come out. After the last fiasco I told them to forget it.
I have spoken to a plumber friend of mine about a new combi and he has suggested putting in un-vented system due to the size of the house and the fact I am going to extend the loft with an extra shower room or bathroom and maybe another bedroom.
My friend has suggested putting in a 26kw Viessmann Vitodens 100-W system boiler with a Imi Tribune 250 Un-vented cylinder.

Is this a good quality system?
Is it necessary for the extra £1000 over a new combi since only me and my girlfriend live in the house?
Will it be able to warm the house better?
Will it be cheaper to run than my current Combi?

Thanks for your replies in advance
Ben.

 

[gas4you]

You don't say how many bathrooms etc you have

Although an unvented system will be the best option, I would, especially if you only have 1 bathroom, look at the combi option.

The Veissman is reputedly a good boiler, although personally I don't like them, but I would go for a better unvented cylinder if you go down this route

 

[rustydonkey]

I currently have one bathroom with a bath, shower, and a sink. I am looking at having another bathroom with a shower and possibly a bath.
Why do you dislike Viessman boilers? The more info i can get the better. Why is the un-vented system better and which cylinder would you go for?

Thanks

 

[gas4you]

I do not like the build quality from the limited few I have seen.

I have also heard bad reports about their aftersales service.

If you want the best then go for an ATAG boiler and an ATAG unvented cylinder. Dutch quality and reliability at its best.

You could also look at the Vaillant Ecotec Plus 937 storage combi. Excellent product.

Whether you go for a powerful combi or un-vented cylinder, the same criteria will apply, ie you will need at las 20-25 litres/min cold mains flow and about 3 bar cold mains pressure into your property.

Without these figures being achievable you will be wasting your hard earned money on either of the above systems.

 

[JohnD]

I went for a Vitodens 100 Compact (the non-combi one). As it has fewer parts than the Combi my expectation is that there will be less to go wrong.

But be sure you get a Viessmann-trained and approved installer (that way you get a much longer warranty) and try to confirm that he has fitted several of this model before. My installers had done Viessmanns, but not the 100 Compact and it took them several goes to get it right.

I would also go for a one-man band rather than a firm with one Viessmann expert who is not the person who actually does the work in your house, and might be on holiday. I think that would have saved time getting mine right.

This is worth mentioning because the 100 Compact is not a common boiler, so there are not a lot of people familiar with them.

Now it is running correctly I am perfectly happy with mine.

(cue RGIs shouting "A boiler's just a boiler, I can fit anything)

 

[gavinda]

i would say theres a great deal of difference between boilers, but id certaily go for a more comon boiler. better chance of gettung it repaired. remember you get what you pay for.

 

[JohnD]

I went for an Approved Installer with his premises a couple of hundred yards away from my home. Thought I'd done well but I now know some extra points to check.

 

[sambotc]

What took a few attempts getting it right John?

 

[JohnD]

incorrect wiring initially (the boiler controls the pump, and makes it run-on for 12 mins after it stops firing). I believe it was wired wrong twice. I looked at the diagram in the book with the electrician, and I didn't find it clear either (I had obtained a Datasheet from Viessmann, which was better, but it only covered the 100 Combi, not the 100 Compact and I then unsuccessfully attempted to get a 100 Compact Datasheet from Viessmann.

They made a mistake with the existing flow/return pipes somehow (this caused the Flow Detect Switch to signal a fault and prevent firing), wasted time removing my Spirovent, thinking that was interfering with flow, and ordering a replacement Flow Switch before realising the error made by the junior installer. IMO this would probably not have happened with a one-man band where all the work was done by the expert installer. The pump and 3-port valve and stats and controls and wiring were all replaced as part of the install, so it was quite thorough. The boss also corrected the run of the gas pipe where it was fouling a kitchen appliance as originally fitted. Workmanship and materials were good, so far as I can tell, apart from these mistakes, and I did not pay for it until working.

Mine is a Y-plan and IMO they were not familiar enough to know that the manufacturer's "normal" setting of the boiler stat is 60C which means it is bound to short-cycle on HW only when the cyl stat is also 60C (I ended up tinkering myself, and fixed it after advice on here, by turning the boiler stat up and the cyl stat down to increase the heat transfer (seems obvious once you know)

I was rather embarrassed that a sensible and well-informed householder like myself, carefully selecting his boiler and installer, and paying for a nice-quality job, had so much trouble getting it right. I am sure that if they had been more familiar with this model, the wiring and the short-cycling problem would not have occurred, the piping mistake might have been spotted earlier, i don't know, mistakes do happen, but once you have seen that one, it is very quick and easy to detect another time.

 

[rustydonkey]

What is a good quality cylinder?

 

[BigBurner]

Two bathrooms. Get a Broag 28C combi for now. When you extend to a second bathroom, get another. See this thread, re: two combis:
//www.diynot.com/forums/viewtopic.php?t=159790&start=0

 

[simond]

I don't think he wants your bl**dy Broag.

Can't you stop going on about them, we know you haven't fitted one. Go and get some Broag brochures and hand them out in the High St, get it out of your system.

 

[BigBurner]

I don't think he wants your bl**dy Broag.

Does he need a Kidd?

 

[simond]

Doubt it.

 

[rustydonkey]

I think Imi is now Range, Can anybody confirm this? From what I have found out I think this is the cylinder he is talking about.

http://www.boilers2go.co.uk/product/RANGE_TRIBUNE_TI250_SS_UNVENTED_IND_CYL

I can have a Santon cylinder a bit cheaper or a MegaFlo for £300 more. They all seem to have a 25yr guarantee. Will the unvented system give more powerful showers?

My mate has done the Viessmann course so I would get a 5yr Guarantee with the boiler.