New condensing boiler installation - truth or lies

I've had a British Gas man around today to quote for a new condensing boiler. My existing set up is:
o boiler - very old - over 25 years, wall mounted. Flue straight out back to outside above head height (about 5-6ft to next doors house). o gavity fed hot water with thermostat on tank, controlling valve (motor currently broken so manually fixed open although I have a new motor for it) and boiler o water tank in loft feeding central heating o one room thermostat in hall o most (not all) radiators with TRVs - radiator in hall where room thermostat is located does have a TRV. o newish (3 years) programmable controller with separate CH and HW settings and 1 hour, overrides. o relatively new (3 years) myson cp53 pump.
During the conversation he told me:
1. it is against the law to not fit condensing boilers now. From other postings this would seem true.
2. They would remove the room thermostat as it was bad to have it in a room where radiators have TRVs. Other posts to this group seem to suggest having a room thermo is OK but not to have TRVs in the same room.
3. When I said I wasn't sure if we had a bypass and if we went all TRVs I thought we'd need one he said all their condensing boilers come with a built in bypass.
4. Regarding placement on the boiler he said manufacturer specs said their must be at least 600mm space in front of the boiler although it was OK in a cupboard so long as with the doors open their was 600mm in front. As a result he suggested installing it around the corner from where it is now.
5. Our gas meter was not earthed and so they would have to earth it all. I'm not this is true since I remember a large earthing strap behind the gas meter where the pipes come into the house - I cannot investigate this now.
6. condensate from new boiler was not a problem since the boiler will be sited next to a soil pipe.
7. our system was wrong be cause there is not at least 1.5m between the top of the boiler and where the pipes go into the cylinder. This would cause our boiler to switch on and off alot when only heating hot water.
8. conversion from gravity fed to fully pumped was a time consuming process. Some sort of air valve would have to be installed - I'm not sure exactly about this. The system would have to be fully pumped which mean installation ot 2 new valves and pump.
9. It was around 3 days work.
10. the quote left has a "the effects of pluming have been explained" but they never were.
11. He criticised the current electrical installation a lot. Wrong cable used throughout - should all be flex - and told me a horror story about a house fire near us caused by wrong electrical installation where the insurers were not fully paying out after identifying sub standard electrical fitment of halogen lighting.
12. When I asked how he would calculate what size of boiler we'd need he said he didn't need to as it would be a modulating condensing boiler which constantly monitors the exit and return water temperature and adjusts automatically. I did not think this was a satisfactory answer since clearly if he fitted a 1KW boiler it would not sufficient (absurd example I know).
Needless to say I was less than impressed but then came the:
Total quote was for 3498 including VAT (and 100 trade in discount) with some significant numbers being (not including VAT):
British/Scottish Gas 330 HE Condensing Boilrer (inc labour and installation) 1559 specialist building work (3) 174 can't imagine what this was other than repositioning flue connect boiler electrics and test 64 glow-worm Xi std horizontal flue (800mm) 154 glow-worm Xi flue extension (500mm) 28 glow-worm Xi 90 flue elbow 31 radiator valves (15mm angled W/H & L/S) 26 Now he has left I don't understand this as we never spoke about adding radiators or valves. controls pack (2*22mm 2Port) Prog. (UP1) 307 convert to fully pumped 22mm (5mtr head) 312 powerlush - 195 install ME bonding 112 exectrical and mechanical supp bonding 79
there was other stuff like waster disposal, pipe insulation, fit pipe insulation etc.
I was somewhat surprised by the size of the quote and the cost of the boiler - seemed pricey to me.
Any useful comments?
Martin -- Martin J. Evans Wetherby, UK
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<<<snipped>>>
What type of guarantees do you get with all this? Are they also providing break-down cover for the first X amount of years on the whole installation?
Have you checked out the price of the boiler on the web?
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On Fri, 17 Jun 2005 14:38:36 GMT, "BigWallop"

I think he said 3 years included but I can't find that info in the quote.

The boiler is exclusive to British Gas - The British Gas 330, so I can't find it elsewhere - unless someone else knows better.
Martin -- Martin J. Evans Wetherby, UK
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A few BG engineers have told me that their "exclusive" boilers are rebadged Worcester Bosch's, which would also explain why ex-BG engineers favour fitting WB boilers like the one that just did mine.
Check the Worcester Bosch equivalent boiler. You may find it's virtually the same.
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wrote:

I think that we may presume from the above that he's proposing a rebadged Glow-worm. A Glow-worm 30Hxi is 795 including VAT at
http://www.discountheating.com/wallcondensingtraditionalgas/30hxi.htm
Whether you need 213 of flue extensions is doubtful

Seems typical BG gas price to regular readers here
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wrote:

Thanks for that - it helps to know what the boiler might be. All I have is some marketing stuff from BG telling me how good it is. SEDBUK A rated, NOX class 5 emissions, SS heat exchanger, on board diagnostics, "Continua" electronics allowing the boiler to continue where others may fail (hmm), adjustable for my future radiator needs, frost protection.

I didn't get that either. The boiler is only moving round an inside corner so it will be less than 0.5m from the outside wall and 213 + VAT for flue extensions seemed rediculous.

Thanks for th response.
Martin -- Martin J. Evans Wetherby, UK
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Well, there are exceptions, but these are unlikely to apply to you,.

You need a "boiler interlock" that completely turns off the boiler when the house is hot. Normally this is supplied by the room thermostat. If there is none, another method must be used, such as a flow switch on the heating circuit. Did the installer indicate how boiler interlock was intended to be achieved?

Without knowing all the boilers they supply, it isn't possible to say. Some boilers have internal bypass, some don't. However, there's no reason to disbelieve, really. You'd need one even without all TRV, as you are going S-Plan.

Sounds normal, assuming the move around the corner is to improve aesthetics, or flue location.

Sounds good. Better than some where they use a "soak away", which is a euphemism for sticking a bare pipe out of the wall which rots away your patio.

The vertical height of the boiler and cylinder is no longer relevent, as the system MUST be converted to fully pumped by law. Fully pumped systems don't care about heights.

There are other methods, but the 2 valves and the pump is one of the most common, simplest and reliable. It is called 'S' Plan. Some of the conversion will be to make it a sealed pressurised system, rather than gravity fed. This is well worth doing.

Could well be.

The exhaust terminal will shoot out loads of visible steam, especially in winter. This may seriously annoy the neighbours, even though the exhaust is actually cleaner and less poisonous that the invisible plume of older boilers.

There is no need for the cabling to be flex. Indeed, apart from the final connections to any immersion heaters, external pumps or zone valves, fixed T&E wiring is actually superior. Flex is often used because it is easy to get multicore versions which are more convenient, though.

Ignore friend of a friend horror stories. Almost certainly not true.

He is actually correct. Most modern condensing boilers have a much greater maximum output than any normal house requires. (Some manufacturers have recently produced throttled back versions that might struggle on a big house, though). You need to have a 10 bedroom 1660s place with no glass in the windows to exceed the capability. (Well not, quite, but if the calculation did show a bigger boiler was needed, the correct approach is to fix the house insulation, not fit a bigger boiler).

Not actually that bad for a BG quote. Still much higher than a good local engineer, but not in their normal stratispheric regions, given that the quote includes lots of additional work to the actual boiler swap, such as the fully pumped version, movement of the boiler, updating of controls etc.

The Glowworm HXI/CXi/SXi is the boiler that is currently rescuing Glowworm's reputation. It is certainly not scraping the barrel by going for a cheap boiler.

Well, BG always give the most expensive quote. Make sure you phone round some local non-chain places.
Christian.
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Chistian,
Thanks for the info.
On Fri, 17 Jun 2005 16:34:30 +0100, "Christian McArdle"

So I gather. It would be really difficult to argue in my case.

Not that I recall. A question I'll ask of him.

Actually moving it round the corner increases flue length. The problem occurs because the current boiler is on an end wall right up to a boxed vertical section carrying the soil pipe, other pipes and pump. On the other side of the corner my wife wants two double wardrobes and if the boiler was replaced in the current position there would only be 29cm space in front of the bolier. He suggested putting the boiler on the wall to carry the wardrobes inside one of them. I assumed the corner flue piece he quoted for was to take the flue round to the existing flue exit hole which is why I was also questioning the "specialist building work".

He didn't explain it must be converted to fully pumped he made it sound like our system was wrong and the new one would overcome this error.

I think this is where this "air vent thingy" come in - it was something to do with keeping our system open. He definitely said they would not be converting it to sealed system because some of the pipework is in concrete and a leak would be a big problem.

"shoot out" does not sound so good. It is less than 3' to a fence and then less than 3' to my neighbours house with the fence lower than the vent. Shooting out whilst someone is walking down the side of the house (either on my side or my neighbours) wouldn't be good.

The valve behind the cylinder is connected to a junction box by T&E. From here 2 T&E come down to another juntion box where flex goes off to the boiler and programmer. The immersion heater is flex. It was the T&E down the boxed section from my airing cupboard to the jn box below he specifically tutted at.

That is very good to know. This one worried me the most.

Have done so.
Thanks again. Your post has helped sort a few things out for me.
Martin -- Martin J. Evans Wetherby, UK
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Martin Evans wrote:

Isn't it water vapour, rather than steam? I think it's quite pretty, especially on a frosty day.
I don't think - although I could be wrong - the flue gets dangerously hot. AFAIK it's acceptable to have the flue somewhere someone walks past provided there's a wire cage over it to prevent direct contact.
What must be carefully positioned is the pressure relief outlet, which shouldn't shoot out anything in normal circumstances, but will shoot out boiling water and/or steam if Something Goes Wrong.
Owain
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Owain wrote:

The flue gas temperature will be significantly lower than with a conventional boiler. So it is better to get hit by the output from a condensor than a conventional boiler. The only real difference is it is cold enough for the water vapour to be visible.
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Steam is actually invisible (and highly dangerous as a result).
Glow worm have recognised the plume as being a problem and make a kit to extend the discharge upwards and away from the flue wall exit point.

The cage is a throwback to flue terminals which got hot enough to brand you. A cage was to stop this happening so as a result you got a criss-cross wire pattern burnt into your flesh as a result<g> The requirement is still included in the GSIUR of course

True
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John wrote:

I find it supprising that people get so upset at the sight of a bit of water vapour... They must get really scared when they make a cup of tea! ;-)
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On 18 Jun,

What I wonder about condensing boilers is whether the low temprerature plume can spread legionella. Can water sit anywhere at a suitable temperature to allow growth of the bug. What precautions need to be taken to prevent this. Has a risk assessment been done?
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Several points.
- In the area of the burner the temperatures are considerably higher.
- Flues are normally arranged with a slight slope back towards the boiler for nominally horizontal runs so that water condensing in the flue goes mainly back into the boiler. This is also to stop it dripping out onto the ground outside.
- Internally in the boiler, there is an arrangement for the water to run down into a trap from where it then drains out. Hence there is not really a place where it will remain stationary for long.
- The condensate water is mildly acidic.
- Condensing boiler technology has been in use elsewhere in Europe for 20 years and there are not large outbreaks of Legionella reported as a result of its use.
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wrote:

to
tea! ;-

plume
to
this.
More like 40 years.
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My Keston, which ran at around 45C flow through most of the winter, did manage to grow something a bit jellyfish like in the bottom of the heat exchanger (which would have been slightly cooler than 45C). This then blocked the condensate drain causing the heat exchanger to start filling up until it was making quite a gurgling noise and failed to light. I didn't conclusively prove if the jellyfish like thing was animal, vegetable, or mineral and it was broken into small pieces by the time I got it out.
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Since when has steam been considered low temperature?
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It's not steam. It's water vapour. Like clouds, if you want.
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Never, but you don't get steam from a condensing boiler flue.
It produces water vapour at temperatures < 100C, and at normal operating temperatures, below 60C - hence the reason for the question.
However, in practice, legionella does not seem to have been a problem with condensing boilers
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<snip>

problem
Yet....
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