Vague. What is a zone. Anyone who knows heating will tell you a zones is "an independently controlled, in time and temp, section of the heating system".
Like many of these regs they mean many things to different people.
Read my post. I'm not saying you have to have TRVs but if the doc says you have to have zones I don't see how you get around that (or why you would want to). Yes, you can discuss things with the BCO and he can sign off anything but realistically if it says zones you need zones. A BCO is extremely unlikely to sign it off otherwise. And zones being what the doc describes a minimum of temperature control.
Hells bells what is the problem. Has everyone taken argue pills or something.
I was simply pointing out that the Approved Documents are a guide and nothing more than that. The methods described in the contents are not mandatory
To quote
"Approved Documents are intended to provide guidance for some of the more common building situations. However, there may well be alternative ways of achieving compliance with the requirements. Thus there is no obligation to adopt any particular solution contained in an Approved Document if you prefer to meet the relevant requirement in some other way."
Even in sections 1.38 and 1.39, the terms "would" and "could" are used
- not "shall"
.andy
To email, substitute .nospam with .gl
It doesn't define what a zone is. Don't assume.
Where does he accurately describe that?
Andy takes them all the time.
Yes it does, in sections 1.38 and 1.39.
Hi,
Why not make a stainless flue gas heat exchanger for a conventional oil boiler, and use the low grade heat for UFH/HRV/DHW preheat/kickspace heater?
I'd expect oil to increase in price over inflation in the next 10 years, this will speed up the payback on any up front investment.
cheers, Pete.
They also say:
"Thus there is no obligation to adopt any particular solution contained in an Approved Document if you prefer to meet the relevant requirement in some other way."
This is the point I made earlier. It has nothing to do with whether or not a 'zone' is defined.
However, some people have a brain fart and interpret that to mean:
"Everything in this document is rubbish. You can make your walls out of newspaper if you like."
They don't seem to understand that the "some other way" actually involves ensuring similar energy savings/safety whatever and justifying it to the BCO. If using some other method, you should be able to justify that the proposed solution as at least as effective as the officially suggested one.
Christian.
Cos I'd need to convince Building control it was ok and given that boiler is already about 90% efficient that only leaves 10% to get. GBP40 pa tops. Not worth the effort. I could probably save more shopping around for oil, improving insulation etc. It would be a very risky endeavour with unknown gains.
Why? The US is wedded to the car. They drive everywhere and the layout of their shops support that. If oil was more expensive so would be US petrol. A much as I think they should pay more for petrol to cut down their emissions I don't see it happening. Plus the last time the Arab states hike petrol prices the world went into recession which hit them too. Now they adopt a balancing act to get the biggest income, that is the middle ground between cheap oil - large sales and expensive oil - low sales. So why should oil increase in price? It might fluctuate some, but that's all.
Christian.
Hi,
90% is very good for a non condensing boiler, though oil has half the latent heat losses of natural gas.One way to do it would be a fan assisted exchanger in parallel with the flue, then there should be no net effect as the flow is balanced.
I think it's their intention to get oil prices lower, but having tax breaks for unnecessarily large vehicles won't help in the long run.
cheers, Pete.
The straightforward answer to Tom's question, "11degC across Boiler, why?" is that the 11 degree C is not a requirement at all. It is merely the temperature rise from return to flow that the particular boiler can, and does, achieve at the specified water flowrate when it is burning flat out. Simple physics says that "Flow Rate X Temp Rise" is proportional to "Heat Input X Boiler Efficiency".
The boiler is a heat source and so (obviously) generates a temperature rise in the water flowing through it. The remainder of the system is a heat dissipator and the temperature drop of the returning water is determined by radiator sizes, room temperatures, air changes and so on.
A boiler can equally well operate at full output with a smaller rise, if the system pumps at faster than the quoted rate, and conversely a lower flow leads to a greater rise, possibly causing the limit stat to turn off the burner, or turn it down if a modulator.
Radiators are also spec'd to give out their stated output at a certain temperature drop and average temperature. This is commonly 11 degree C, and is possibly the reason that so many believe that the drop is 'supposed to be' exactly that.
As has been mentioned in the thread above, systems can and are designed for different flow/return temperatures to exploit the efficiency characteristics of different systems. The actual temperature difference the system uses depends on the c/h system designer's preferences as admirably discussed above, and refers mainly to the case when the system is going flat out in winter.
Phil The uk.d-i-y FAQ is at
Read the installation instructions. That is what they say.
This tends to be the case with combi's in small flats. Most combi's can heat a 5 bedroomed house. The modulation really helps. Early non-modulating combi's cycled like crazy as the temp rise was far too great.
Thank you all for a magnificent response to my question, I understand a lot more now and I can see my way forward. I'm most grateful to you. Warm Regards Tom
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