Best let your registered gas installer advise on the particulars. You're obviously alert to some imperatives but there may be others you are not.
Given the sort of muscle [kW] you seem to be threatening the roof space with, a 28mm minimum gas pipe is a virtual certainty.
An existing water pipe of suitable size may be gas tight but it may contain a compression joint somewhere hidden which is a no, no.
Or even a wee bit of plastic hidden somewhere en-route, also a no, no.
I was wondering if anyone here had heard of, or experienced first hand, anything similar to the following:
On Wednesday 28th Feb National Grid (NG) carried out emergency repairs to a leaking gas main in the road outside my flat. They turned off the supply to several buildings (large terraced houses converted to flats) in the street. Having completed the work they are refusing to reconnect the supply. It seems that they want to replace the copper pipes inside the building with PE pipes. The source of the leak was outside, there is nothing to suggest any problem with the internal pipe work and NG did not carry out any tests on the pipe work inside. They are unwilling to run the new pipe work along existing conduits and are insisting that the replacement pipe work is surface mounted on walls in the common parts of the buildings. The reason for not using existing conduits was given as “regs”. Does anyone know what these new regulations are and how can I get hold of a copy of them? If the tenants have a site meeting with NG, we do not want to be told that it all has to be done their cheap and easy way due to ‘regs’. It appears that the tenants are being held to ransom by NG who are being very elusive at to why exactly they are carrying out their action and have suggested that this may take months to resolve!!
Any comments/suggestions gratefully received.
(yellow) PE pipe is DEFINITELY NOT suitable for running exposed above ground in 'common parts' of a building. If the existing pipes in these areas ARE copper, they're also wrong. They should be STEEL.
It all sounds jolly exciting.
Gas-News has a busy forum and a seemingly moribund website. However what you see is just the tip of the ice-berg. Beneath the surface, all manner of things are going on, all the time.
Recently that included an identical situation at a private house where made-up-as-they-were-going-along regulations were cited. Heads they win, tails you lose and all that stuff. Classic commercial bullying.
A bit of judicious whatnot and common sense prevailed there. Punter happy. The others I don’t know about.
Sounds to me like we can all learn from this. Perhaps NG should be asked to set out their full specification or whatever, qualifying all their arguments, in writing. Ask them.
For presentation to all the residents, editor of Gas-News and anyone else [plus magazine editors ?] who fancies an interesting evening at a local hostelry which will no doubt, grant a room FOC, in exchange for custom [did that near here recently and mine’s a tonic with ice but no lemon].
In the matter I mentioned above, NG simply wanted to engineer a situation which better suited their future purposes, without regard for the consumer involved. Again as mentioned elsewhere, we are not talking about an ‘orrible beast from Greek mythology but one human being using their perceived power to persecute another.
A bit like the sordid mess that was the reformation, and still is.
We’ll need to see full details on the table before booking a room somewhere.
Meanwhile get yourselves organised and take me to your leader.
The bit I like, same as the last case, is where they disconnect first and ‘ask’ afterwards.
Does NG come under the Local Government Ombudsman, Parliamentary Ombudsman or some other agency I wonder. I’ll find out today as I’m desk-bound with paperwork.
Sounds pretty outrageous/incompetent, JP. I'd want to get the facts set out, quickly. I'd find out who the individual is who is making the demands, what his position is, and who his boss is. Speak to them if you can, but certainly write (Recorded or they'll lose it) to the boss.
Also call Ofgem, who can be useful.
Regarding the internal pipes, I wasn't sure they had to be steel in common areas - plenty aren't. Does it come down to fire protection requirements? Perhaps JB has a link - which would be useful to JP.(as well as me!)
Thank you for the prompt responses. I was not sure whether I was in the right forum but given your help so far I will add a little more detail if I may.
Firstly I assume the pipes are steel not copper, it was just a layman’s assumption by me.
A NG representative met the chairman of the residents committee to discuss the replacement of the internal pipe work (leading from the main to the individual meters within flats) although he would not say exactly why the pipes needed to be replaced or under what regulations the work needed to be carried out. It appears that NG is starting a policy of exchanging existing pipes for PE, although I can find no official mention of this policy, and they are using the excuse of the leak outside our building as an excuse to change our pipe work. He offered two options:
1. To run surface mounted pipes inside the building through the stairwell.
2. To run an external pipe from an adjacent street along the outside rear wall of five so far unaffected buildings. This would involve petting permission from the owners, erecting scaffolding and would cost c. £200k. I assume they would get permission from the other owners by turning off their gas and then pointing out that they could only get re-supplied through the new pipe!
Both of these solutions are unacceptable to us and the chairman contacted the boss of the guy he met on site. The reply was as follows:
“I have now spoken in depth with Ron Bender, who you met on site.
I see no reason for me to have a site meeting with you, as I am in full agreement with Ron's assessment of the situation.
Ron will be happy to work with you towards a solution for this pipe run.
Robert Stamp Bsc, Ceng. MIGEM
Ops Eng Technical
National Grid (Gas Division)
Mobile: 07836 285515”
Three requests for the ‘regulations’ have met with no response.
All the directors and some residents met last night and our plan of action is:
1. Continue to contact NG including a letter to the CEO (The longer they stall and evade, the stronger our case).
2. Get hold of the regulations.
3. Get an expert in the matter to help us, and if necessary come to a site meeting, and refute NG’s claims that their solution(s) is the only option.
4. Contact energywatch/ofgem etc. (They really need there to have been 10 days of dialogue before a complaint is made so we are holding for a couple of days.
5. Write to MP and local council.
We feel that we are the small person banging against the wall of bureaucracy. NG seem to be holding us to ransom and time is on their side. It is outrageous that they are causing the suffering of many very young children and some elderly residents just to implement some ‘secret’ plan.
How are we doing? Anything else we should be doing and any other advice?
Thank you for your help so far.
Now you've given me something to work with. Plenty of meat on that bone. I'll be back shortly.
Amazing, the speed of light on the internet!
Thank you Les.
There are clearly two separate issues.
I gather there was a gas leak in the highway and that could (should) be fixed, then the gas supply restored as before. That is the first priority, all else [for now] irrelevant. Forget the pipes, materials, routing, personalities, global warming (except where you live) etc.
Create a massive emailing list and if you write to anyone, send copies to everyone, every time. Saturation bombing [with paper] the order of the day.
As you have a residents’ committee, serve notice under the County Court Acts immediately on the CEO [personally] with a view to ‘oral examination’ of said CEO in front of an audience which could include the Ofgem, press, invited councillors, MP’s etc.
If they will not agree to a meeting, that way you can insist on one, unless the CEO wants to risk a charge of contempt.
You know what questions to ask that you want answers to.
Diistrict Judges run a tight ship. Standards of discipline must be maintained. You and any entourage will no doubt remember that and the CEO will know that.
Stay focused on the principal issue. Restored gas to grill the bacon.
The poor sods at NG have the task of delivering more and more gas [global warming] through an aging infrastructure. So they’re going to beef up pipes to take much higher pressures and deliver more gas [global warming].
No reason why we can’t co-operate with such a strategy [I would] for the benefit of human kind.
Seems to me they’re trying blackmail rather than dialogue. That I cannot condone. They must be stopped now. They must be beaten back and learn to behave properly in society.
Focus on ONE then we’ll discuss TWO over a bacon butty.
Is this a case of there being internal meters which they want to put on the outside of the buildings?
They often want to do that, but I don't know what rights they have to make the changes.
They recently did exactly that to a row of terraced houses converted to flats in Wandsworth, where I do several Landlord's tests. NG didn't seal the pipes properly and generally made a heck of a mess. I and the landlord both contacted NG. Must see what if anything has been done about it. They would have needed access to all the properties to make it right.
They used steel, to connect between the new external meters and the old positions, which were just inside the front doors at street level, so not very intrusive.
Firstly thank you, and secondly, you are perfectly correct. There are two issues, the main’s leak and the replacement of the pipe work. (Chris: Thanks - There currently appears to be no intention to re-site the meters although I am now wary that that will be their fall back position! However the buildings are listed so there are severely limited options for the front).
NG are using the first issue as a catalyst for the second so you are right, what we want, given that there is currently nothing wrong with the internal pipe work, is the immediate restoration of the gas supply. However without knowing their reasoning, any arguments we put up are probably going to be out flanked. While they continue to refuse to supply us with documentary evidence supporting their action, our case gets stronger. However we are under siege and the rations are getting low.
A lot of companies have an unwritten, but official, stalling procedure when dealing with customers. To test this I hope that a letter to Robert Stamp’s boss cc. to the CEO, Ofgem/Energywatch, Trading Standards, the local MP etc will blow a hole in this and effect some immediate action.
What is the process for serving notice under the County Court Acts? Just get on to our solicitor?
Thank you all again.
You can do the business online at:
But you must serve notice first, which simply means a letter to the CEO setting out your wishes. That letter can of course also be sent hither and yon to the UK population or part thereof, being endorsed as such.
Be polite but firm and don't bluff. Cost is pennies.
Thank you. A well written letter will act as a serious threat and as often as not get what you want without further action. Given the alternatives of either attending a court hearing, with the associated cost of the CEO's time and legal expense at £££ per minute, or writing a one line memo to a subordinate to 'Get the matter sorted', hopefully the latter course of action will be taken.
Unfortunately I have a nagging concern at the back of my mind. Unable to find any reference to any similar action elsewhere I think that this policy may be very new. We may well be a kind of test case and the results of our conflicting interests will set a precedent for the future. Consequently NG may be willing to throw everything into this one!
The concept of the County Court is that anyone can bring an issue at minimal cost. It is actually arbitration hence they dropped the expression 'Plaintiff' following the [Lord] Woolf report and substituted 'Claimant'.
The other side can have an army of Barristers but can’t claim a penny for them.
The trick is to avoid it anyway if possible, as I would. But they need to know you mean business and are not bluffing.
Your issue is ‘why can’t they re-connect your gas’ and nothing else. And if they really cannot, as you’ve already said, why are they dithering with an answer. I smell something and it is not gas.
Be seen to have checked also with OFGEM and make sure they don't dither.
Go get ‘em.
Thank you to everybody for their responses. Apologies for rather hogging the board for the last 18 hours but hopefully this information will prove to be of use to others.
I have just spoken to man who has spoken to a man. The identity of the second person was withheld but it was intimated that it was someone pretty senior at NG. It seems that this is going on all over the south of England! As a result of the conversation, I have sent the following to my fellow directors:
“1. NG is just stalling.
2. Immediate use of a lawyer is needed. Firstly they have no authority to withhold gas supply unless there is a danger. (At no point have they suggested that there is a leak and its seems unlikely that there could be leaks in all 4+ buildings). Charge them with exceeding their powers and providing false information. We need to demand that they put in writing their suggested schedule of works and provide all supporting regulations. We need to state that this is necessary so that we can consult our 'expert'. Reference to the two solutions in point 3. will indicate that we are speaking to someone who knows the business.
3. There are two alternatives to their suggestion:
a) Encapsulation of current pipe work
b) Polymer filling
Both these are expensive but they are solutions currently being used by NG in the south of England.”
It seems that this is becoming a widespread issue. Interesting that NG failed to offer the options outlined in point 3.
Mighty interesting and keep us informed but stay totally focused on objective number one.
If there are any meetings locally to discuss the matter let us know in case any of our visitors wish to attend and give feed-back.
You can now be sure that many are tuning in to this thread as it has been eloquently delivered by yourself, is newsworthy and without doubt in the public interest.
Do not go away.
I will certainly keep everyone updated although I doubt there will be much more before next week.
Can anyone flesh at some technical terms for the encapsulation and polymer infill processes, as that will add to the credibility of any letter our lawyer sends?
Hang in there for Chris or one of the others with a physics / chemistry oriented background, at Masters level as I recall.
Seems to me that an avenue for counter-attack may have been overlooked. Do NG have a right to pick and choose to whom they supply gas, or do they have a statutory obligation to install a gas supply to anyone who wants it?
If the former, I suspect NG will win this argument, as no ordinary commercial organisation is obliged to do business with any particular customer, and has the right to stop dealing with them without giving a reason.
However, NG are NOT an ordinary commercial organisation, and it's probably the latter (subject to conditions like the existence of a local gas network). They have extraordinary powers and probably extraordinary obligations as well, probably rooted in legislation. Identifying and reading whatever Act governs NG's commercial activity will probably reveal their obligation (or not) to supply gas to any particular customer or set of customers.
But they are not a supplier. They are a gas transporter. They store it and deliver it.
And that other case I referred to, identical in principle, was a lone householder.
Exactly the same MO but the commercial thugs were beaten back.
Fair enough Les, but I meant NG physically supply the gas. The gas 'suppliers' don't 'supply' it at all do they? They just provide metering and billing services. NG do the delivering as you said. Presumably they bill the 'suppliers'.
Same question remains. What statutory obligation (if any) do NG have to deliver gas to any particular dwelling?
Trust me on this. It's a bit like Network Rail. They don't run the train services.
And while NG are busy doing nothing, the suppliers are losing ££ from the fare paying passengers.
If there is nowt wrong with the pipework then they must be forced to re-connect so that democracy can prevail and be seen to prevail; A nice little story for the local rag.
Had there been some legislation then bits of paper containing all the legal data would have long since found a way through relevant letter boxes. I conclude therefore that there is no legal basis, until proved otherwise.
Power to the people. Well their gas cookers anyway.
Good excuse to take 'er indoors and the kids out for a nosebag tonight [but keep the receipts].
Installation methods referred to above may be described in IGE publications which I don't have. I do have pdf of
BRITISH STANDARD BS 6891:2005
Installation of low
pressure gas pipework
of up to 35 mm (R1¼) in
(2nd family gas) —
Copy en route to Les.
The other shoe dropping will STILL likely be the requirement to site meters 'outside' somewhere. THEN there WILL be problems with working pressure on the end of the (now much longer) 'internal' pipework between meter and the actual entrance to each 'premises'.
This particular nettle has STILL not been grasped by NG, CORGI, the gas suppliers, British Standards or anyone else (AFAIK). As a result, to maintain the nominal working pressure REQUIRED by gas appliances (another standard!), the pipework diameter goes up and up. There IS a solution (two stages of pressure control) but no-one seems prepared to confront the problem competently.
So, under precise and controlled conditions we need to the check pressures per address and note any later discrepancy, particularly any that fall outside permitted parameters.
That will mean correcting any meter / govenor, where required, before any meters are moved, to establish that testing and re-testing is done on a level playing field.
Hello again Les
I would like to post this as a new conversation to avoid disrupting the current one, but there doesn't seem to be an option to do this.
I thought you might be interested to hear what was recommended to me by an installer who visited. He agreed that the loft was the correct place for the boiler. He recommends a (high quality) combi on the basis that (i) I might 'get away with' the current pressure (ii) it would create space in the loft and (iii) avoid too much disruption to the bathroom.
I am reluctant to specify a combi. There would be a dead leg of 13m to the kitchen hot tap, wasting water. Flow would be no more than 10l/min. Space in the loft is not particularly vital. There would be no solar upgrade in the future.
Re-reading your posts, I would rather put a system boiler there (weather compensated) creating a primary sealed heating circuit. But keep a vented secondary hot water circuit, change the HWC to a better one (maybe twin-coil) and change the tank. Future solar upgrades would be a possibility. Assuming I could get a 28mm gas pipe up there, I could probably keep all the pipework as it is?
Don’t worry about interrupting, as the others above will be busy forming a posse and generally being a nuisance somewhere South of Watford.
The good news is that if you’re opting for an heat-only boiler [open-vented or system] you will probably not need a 28mm gas pipe. The input rating will be a lot less [half] than a combi needs to be [for hot water]. But your RGI will test that, I can’t from here. Certainly not less than 22mm anyway.
As I recall your HWC will be downstairs and it will have to be upgraded under Building Regulations though I’m sure you’d want to anyway. See the highlighted features on the website in the features section and http://www.gas-news.co.uk/feature8.htm which will require updating with the new Gas-News website. Links there to HW trade associations and some pdf files published before John Prescot gave up his throne to Ruth Kelly.
Again I’d beef up insulation on pipes way beyond any legal requirements, both primary and secondary. You’ll find good stuff in those features on controls [TACMA] which should also have been updated. Remember all standards are minimum standards.
Personally I’d still be studying ways of maximising insulation, that’s where the real savings are, but you’ve already commented on the limitations caused by planning and indeed yourself.
For academic interest I’d like to know the real benefits of weather compensation, set against the carbon cost of producing that wee bit of techo. I’m not convinced but my job here is to be a sceptic. That’s what I don’t get paid for.
Pipework I don’t know about because I cannot see it. But you’ll need a clean anyway so be getting on with the pre-wash for what it costs.
‘Might get away with it’ obviously isn’t good enough, is it. That also means you might not and find out when it’s too late.
FWIW, I reckon weather compensation is EXTREMELY important when correctly installed, especially since it will carry on working indefinitely with no need for adjustment (unlike room stats,etc.!)
By adjusting boiler heat output to match actual building requirement, it will (clearly?) maximise efficiency and should add NOTHING to the cost of the boiler (Honeywell MCBA PCBs often incorporate the logic at zero cost - getting installers to install the external sensor and switch on the feature is another matter!)
... and then someone comes along and blows away my scepticism.
Would agree with you there John.
I have had the Honeywell AQ6000 control system installed in my house for over 10 years. Pity they don't make it any more but the punters could not cope with it. They would not belive the house would be warm unless the radiators were red-hot.
In practice, a weather comp MUST be virtually impossible to adjust, to prevent obsessive knob-twiddlers from indulging themselves!!!
But installers are mostly blissfully ignorant of the potential savings (and simplification) comps can deliver. AFAIK, there is NO mention of them in ANY of the 'energy efficiency' courses we all have to do!
It is also worth pointing out that if you do the heatloss calcs for each room of a building accurately, size the rads accordingly and install a weather comp, in theory there's no need to install any TRVs - the whole system including the building should run 'in balance' with the outside temperature all the time. (In practice, you need the TRVs to fine-tune individual room temps, though.)
The snag is that in most cases TRV’s cannot be fitted in anything like the optimum position or are thwarted by junk, school bags, furniture, hairy dogs or a moggy sleeping. I used to attend complaints of poor heating on new build where storey height curtains covered radiators and TRVs behind were deliberately turned off at night.
As you know people like Pegler have a remote sensor system so the TRV sensors are better positioned. However at one home [old luxury detached bungalow] the customer thought similar sensors were redundant ‘tremblers’ off an old alarm system and buried them, hence the radiators stopped working.
I’d like to see a paper written on weather comp with supporting data.
This is interesting.
I have failed to convince my installer of the merits of keeping an unvented cylinder. He says that
(1) the energy lost in keeping hot water in a cylinder outweighs any savings in water or 'buffering'.
(2) 50% of the UK can't be wrong for installing combis.
(3) by upgrading the mains, the comment that I 'might just get away with it' becomes redundant (although I have no idea how much a mains upgrade might cost - and if I invest in that why don't I put in a thermal store?).
(4) the weather compensation doesn't work properly in Viessmann's 'system' boilers because the valves are inside the boiler (not quite sure what this means).
It doesn't get any easier to make a choice!!
Well at least you can rub out the pencil and ink in weather comp. Someone will know about that at V, W, the other V or which ever boiler manufacturer you choose. We can’t help on manufacturers. There is also A, B, C, etc
Once upon a time there was a combi club, an affiliation of manufacturers gathered to promote the benefits of combination boilers. That club has now evaporated, presumably because they are a well established marque. The more you fit, the more instant demand there is.
In some areas near here, litres per minute has diminished. One increasingly popular [and now expensive] area includes owners with more cash to spare [like you have] and are lashing out on extra goodies, which demand more water.
If you beef up your supply that may serve a combi well. That does not mean to say it will. No harm to change anyway and usually not that expensive. Once done you can test it. Until that’s done you can’t make any decisions, and we can’t make them for you.
A new pipe may well serve a combi superbly but not an unvented hot water storage cylinder, some of which can deliver far more hot water than a combi boiler. You know what to do.
As a utilities boffin said to me “our job is not to make combi boilers work” [or preumably unvented], adding, “9 litres per minute at the kitchen sink is all we are required to deliver”. Barely enough to keep me in tea.
That said, I doubt the energy-loss argument would hold water if you know what I mean. We’re not talking cheap. In any case they would not be allowed under Part L if they lacked efficiency. See the following for facts:
What will suit an unvented should suit your thermal store.
There is of course the Flowmax thermal store system [SSP model] which I used to call a poor-mans’ unvented. That will fit where your unvented will fit and do more or less the same job as an unvented. Flowmax [or similar] will run off anything that will heat water but like the unvented, if the main supply dries up you have neither hot nor cold water.
Insulation applies with any system. NB: If any insulation boffins are looking in we’d love to hear from you.
I arrived too early at Interbuild a few years back and ran into two desperately anxious people. One who seemed on the brink of a nervous breakdown, citing Installers as the cause of his misery for not buying good pipe wrap. But I never got any info off him.
The other was a rep from Eire who wanted to establish where the nearest big screen was as Ireland were due to play at 11.00. We soon found one and got dug in.
Your installer needs 're-education' (no doubt the way things are going in UK, the special camps on Dartmoor, Outer Hebrides, etc. will open soon!).
A properly-designed system with a boiler with automatic setpoint adjustment so that it only goes to 70 degrees Flow temp when heating DHW and adjusts down to a (compensated) temp of 40 to 65 degrees for CH will allow the boiler to maximise its time in condensing mode (raising average efficiency by at least 5%, more if the building is well insulated).
Heat losses from a Part L compliant DHW cylinder are minimal compared with the heat losses up the flue of a combi boiler at full power delivering hot water. Also, losses from a cylinder will be comparable to those from a heatstore (same construction and similar temperature differential).
The reason for the mass-migration to combis is purely one of total cost on new builds and boiler replacements. Very little to do with overall efficiency.
There are NO 'valves' inside a Viessmann system boiler (or anywhere else, come to that) with any relevance to weather compensation. There IS a valve inside (eg. ) Vitodens 200 models which diverts Return water an external DHW cylinder (the boiler has dedicated Flow & Return to the cylinder). Why the positioning of this valve (inside or outside) might have ANY relevance to efficiency beats the c**p out of me!! Your installer MIGHT have got confused and assumed there was a 'blender' valve inside the boiler to produce a 'compensated' temperature for the Flow by mixing Return and hotter water from the boiler heat exchanger. There ain't! The compensator directly modulates burner output (and also pump rate).
Hi Les/ John
Thank you for your observations - it is really helpful to have impartial advice.
My installer knows far more about plumbing than I do, and I do not want to mis-represent what he told me, so I have quoted it below:
"With a tank you waste energy keeping it warm, and with a system boiler you
can't have weather compensation with out running extra pipes to the cylinder
as the valves are in the boilers at least with Viessmann."
The extra pipes could be important if the cylinder is positioned in the existing airing cupboard on the ground floor and the boiler is two floors up in the loft. I am trying to avoid extra pipes to minimise the disruption to the bathroom on the first floor.
The argument for a store is put by the Water Heater Manufacturers Association (thanks Les):
"Many instantaneous systems are sold on the basis that they are always more efficient as there is no hot water tank to incur standing losses . The other argument is that the boiler only fires up when you need hot water. In reality these claims do not tell the whole story and depending on usage patterns it is often preferable to use storage. A well insulated hot water storage system typically sited in an airing cupboard has a heat loss of less than 60 watts, for seven months of the year this heat is usefully absorbed by the building and all through the year helps to air clothes. The boiler only fires up when a substantial amount of heat is taken from the cylinder and tens to operate for several minutes thus achieving efficient operation. With an instantaneous system the boiler fires up every time hot water is drawn off. This can lead to inefficiencies particularly in the summer when the boiler sheds its excess heat to waste."
The key phrase is 'depending on usage patterns' I think my installer is arguing that our hot water usage patterns (hot water for washing up, washing hands, shaving, showers (2 per day) and baths (1 per week) - total say 120 litres to 140 litres per day) do not justify a store, let alone a future solar option. Perhaps he is right?
However, with a store the boiler would fire up far less often than a combi for hot water uses - only twice a day for 'substantial' demand (showers) compared to about ten times per day for any hot water activities - a saving of 80% in wear and tear on the boiler? But is this negligible compared to the number of times it would fire up for central heating?
The water wastage from a combi - say 3 litres each time a hot tap is turned on? - say 10 times a day for us? - makes roughly 30 litres per day. Perhaps this is also insignificant and I shouldn't be considering it, even if water becomes even more scarce in the south-east and we become metered.
Could it be Steve that your installer has an axe to grind. Many Installers cannot see past their usual practice. " that's the way we always do it" is the usual cry.
Remember that you are the customer and the customer is always right . When you have come to a conclusion which route you want to take tell them what you want and where you want it.
See if you can get about five firms to quote, cos after you have made it clear to them that you know exactly what you want, you will probably find that at least three of them wont bother to submit one.
My installer knows far more about plumbing than I do
That, unfortunately, is an assumption. One that most customers seem to make. It may be true in your case but equally it may not. With some diligent homework the customer with an enquiring mind can quickly overtake the average UK plumber who has grown lazy thanks to a never-ending flow of work from customers grateful for his attention, no matter how slap-dash.
The average UK consumer seems to have a overly fond belief and confidence in the competence of his/her plumber, often misplaced judging by some of the appalling work I've seen over the years. Micro-managing your plumber until he proves he doesn't need it is a good strategy in my opinion.
I think the plumber is good and I don't question his motives at all.
It's just that my wife and I are very suspicious of combi boilers. His main argument for the combi seems to be cost and convenience, but I can't see why the marginal cost of a new vented cylinder should be significant.
Best get a quotation for each option.
In addition to the unvented, you’ll need zone valves, auto by-pass and other bits, that would not be necessary with a combi.
Steve it's Horses for Courses.
All too often when a plumber has only one nag in the stable it turns out to be a hobby-horse which he won't get off.
Having seen a couple of examples of this plumber's knowledge and logic, I wouldn't back him.
Thanks for all the messages. I will try and find another interested installer or two and feed back to the forum in due course.
It's true that Viessmann (and some other) boilers have an internal diverter valve and extra Flow and Return pipes to run to a cylinder. Unfortunately, if you want to use (eg.) a Vitodens 200 with the inbuilt weather comp the DHW heating can only be properly managed if you use the internal valve and DHW heating pipes. That's the way Mr Viessmann designed it (Alles in Ordnung, Alles Korrect, usw. if you know what I mean!) There are viable alternative layouts using other manufacturers if you REALLY CAN'T run dedicated pipes.
The very low heatloss from a Part-L-compliant cylinder and the wasted water due to start-up delays on a combi mean that this particular argument in favour of combis really does NOT hold water! Also, many combis now have Eco/Comfort mode switches to overcome the delay and water wastage - by wasting energy keeping the boiler warm instead!!! This tends to confirm that water waste & delay ARE seen as 'combi problems'.
I didn't intend to post again for a bit, but other installers are slow coming forward and this installer has been very patiently helpful in putting his case for a combi, so I can't resist sharing it with your good selves experts as I am finding it more difficult to establish the truth....
Issue: Compromised performance from a combi unless the mains is upgraded.
Installers reply: A combi on your present system will give a good shower and fill a bath in about 8 minutes, without up grading the mains. We could pump from the tank through a combi to enhance performance.
Issue: Unnecessary extra wear compared to a system boiler (fires up every time you turn a hot tap on - say 10 times/day for hot water compared to 2 times/ day for significant hot water demand for showers).
Reply: I know of combi's that are over 20 years old that are working fine. Your statement on reliability is base on ignorance I'm afraid! Boiler manufacturers go to great lengths to ensure reliability, all of them age their boilers in laboratories to find failings. Boilers with premix burners are inherently simple and proving to be very reliable.
Issue: Dead legs resulting in wasted water - particularly to kitchen tap (about 13m) - in total could waste around 30 litres per day on average (3 litres in 30 seconds ten times a day, say) - likely to be more of an issue in the south-east the way things are going.
Reply: Most if not all good combi's have a timed preheat facility to minimize water wastage. In any event another option for your combi is to put it where the hot water cylinder is with a vertical flue, we could pump from the existing tank so you optimise the performance of the hot water.
Issue: My understanding is that heat losses from a Part L compliant DHW cylinder would be minimal compared with the heat losses up the flue of a combi boiler at full power delivering hot water.
Reply: Part L cylinders do lose less heat than older cylinders but heat they do lose. For a one bathroom house with average hot water usage a cylinder is more wasteful than a combi. Now if there was more hot water usage this would
change. Cylinders have to be kept at 60c to avoid legionnaires, combi's heat to a usable temperature of 45c or more and no necessity to raise the temperature of the hot water.
Issue: My understanding is that any internal valves in the Vitodens 200 have nothing to do with efficiency or weather compensation - i.e. they are not blender valves.
Reply: The diverter valve is an energy saving device because it enables the boiler to know that it is heating hot water and hence fire the boiler at a higher temperature than the weather compensated heating water. It also runs
in parallel so that the temperature difference between the primaries and the dhw is never that great. It does not use a thermostat but a sensor that tells the burner to modulate not switch on and off. The diverter valve keeps your system under one manufacturer, and this has advantages too. The controls are harmonised using digital technology not on-off analogue technology, where as a standard s plan involves all different manufacturers and works on analogue technology (which is inefficient).
Issue: I was intending to marry a weather compensating system boiler with a vented hot water cylinder.
Reply: Installing an s or y plan means you cannot have weather compensation on the heating as the hot water cylinder would not reheat correctly.
Issue: I would like future solar upgradeability.
Reply: Inherent in your emails is an over high hope for solar technology. This does and will work well in summer when radiation levels are higher, but can only be seen as a low quality supplement to traditional heating. The
other day I commissioned a system in Hampstead (£5000 on a flat roof) It raised the temperature of the hot water by about 10c to 26c in one
afternoon. This was a house with five people, cleaners etc and a high hot water usage, so it was a good investment. Solar does have some very big pitfalls that if you are not aware about can be costly and dangerous. I suggest you look at the gas saver at http://www.zenexenergy.com/. This is a much better investment than solar for you.
I'm very grateful to my installer for going to so much trouble to try and explain this all to a novice - the reason I reproduce this here is to try and get to grips with the issues. The most contentious one seems to be whether you can successfully marry a vented cylinder with a system boiler with weather compensation - he says no, which I think contradicts the advice from this forum???
We’ve already covered a lot of this ground and I would suggest it is make-your-mind-up time.
Tell the Installer what you want and if he can’t deliver, look elsewhere.
With regard to the zenexenergy gismo, I wrote a report on that beast for one of our major clients recently. Certainly big, expensive retail and you need to study the detail.
Not least a double check valve specified [and other expensive bits not supplied], will further choke the water supply dramatically.
A boiler manufacturer (Alpha?) was showing an external 'recuperator' similar to the Zenex thing, attached to the flue above the boiler, at a recent exhibition.
My major concern about anything like this is what it does to the flue-length calculations. CORGI et al are very sniffy indeed about any modifications to flues of any kind: Zenex would have to provide a written warranty in every case, I'd have thought.
The point about the digital control using a sensor on the DHW cylinder in the control system provided by Viessmann and others is that the controller can modulate the burner to maintain condensing mode for as long as possible whilst still providing a satisfactory recovery time. A simpler on/off cylinder thermostat obviously can't achieve this level of control.
As Les has already commented, I think it must be make-your-mind-up time, based on all the information you have. Your installer must be also be a very patient mine of information!
It was actually the Zenex on the Alpha. Also fitted to a Viessmann in the same trials.
As you’ve guessed there are flue issues to be resolved for the boiler and indeed each model. That would require the ‘notified body’ to approve, with associated expense and paperwork to satisfy Installers it is kosher.
Also needs WRAS approval [potable water] hence the double check valve.
Said to be [in effect] superior to solar technology which is ironic as both Alpha and Viessmann make solar technology, so why the partnership. Perhaps they were hoping that would give them an edge in the RSL market, where the technology was trialled.
Note the date of the ‘latest news’ on the website - February 2006.
Zenex approved connection kits are currently available for Alpha and Viessmann boilers, according to their data sheet.
For the trials they were fitted to Vaillant EcoTec Pro 28 boilers [for which they also presumably had approval].
Battle with National Grid.
Just a quick note to show that I had not disappeared. On the face of it there seems to have been little progress. The lawyers are still ‘on the case’ but seem to have failed to make any headway. The buildings are still without gas and have had no supply since 28th February.
The regulator has sent a letter (dated 12th March) to National Grid demanding that they speak to us with 10 days. It looks like we have been stonewalled on the immediate re-supply of gas. I expect that when we meet, their position will be unchanged. I think that we need to offer an alternative and so show:
1. We know what we are talking about.
2. We have offered a compromise.
To that end I would like to go down the ‘polymer infill’ route as it causes us the least disruption. However I need to know more about the process otherwise Nat Grid will merely say it is not possible. We need to be able to counter every one of their arguments.
If anyone could either point me in the right direction or better still provide information, I would be very grateful.