Multipoint as CH boiler & kettling

[Aidan]

Really? Well That's news to me! Also, news to the Health and Safety Executive.

The definitive document on recognized good practice is the 'Legionnaires' Disease, The control of Legionella bacteria in water systems, Approved Code of Practice and Guidance, L8'. Nowhere in that document does it say the unvented systems are safe because the water is not exposed to air. In fact, on P 35 it mentions 3 types of water system, of which the mains pressurized system is one. The same precautions are required as for any other system.

Tell me where it says the water must be exposed to air. I have my copy before me. Tell me of any document which says legionella requires air exposure.

Well, blow me down. More news.

See 'Essential Information for Provider of Residential Accomodation'

end of first paragraph; "Also, recent research has shows that legionnella does occur in smaller domestic systems."

Read this in conjunction with L8, Page 2; "Infection with legionella can be fatal in approximately 12% of reported cases.

You really are an ignorant and dangerous fool.

[Doctor Evil]

Cases cited? Er, none. A scaremongering general statement.

[Aidan]

You made 3 statements in your previous post and I have shown that all

3 are incorrect, providing references to authorative documents. Anyone can look them up and see that you are very, very wrong.

I'd have to spend some time looking for cases documented by the HSE. The only person who doesn't recognise you as being a dangerous fool is you. I don't have time and can't be bothered to try to convince you.

[Dave Plowman (News)]

Care to explain the minimum temperature recommendation for stored hot water and why it's so high?

Don't bother.

We all know why.

[Dave Plowman (News)]

This fool believes every word in an advert, but not a research document.

[Doctor Evil]

No you have not.

Any specific cases? Er, er, no.

You are naive and unable grasp points with wandering mind. get it sorted.

In other words, you have no cases. Thank you. Go back getting drunk on Scotch.

[Doctor Evil]

The senility is rampant now. He will start up about Gen Miller next.

[Doctor Evil]

More naivety underpinned by senility.

[Doctor Evil]

No. Look it up. Duh!

[Dave Plowman (News)]

There's no point. But I think I can safely say that everyone else will be convinced by your argument, and Drivel doesn't matter because he can't do DIY anyway.

[Egremont]

Sorry about this post, it was just a rash thought as I was going out. As my multipoint heats a Thermal Store cylinder, the vague thought was to ask if any similar arrangements exist to heat a HW cylinder (I suppose using a short primary loop via indirect coil) which out of interest would be an analagous usage of the multipoint.

Having had one microsecond to think about this, I realised it wouldnt be much reason but I'd already pressed .

Egremont.

[Ed Sirett]

I missed the earlier posts. Even if you were to make out that you had not altered the installation (I'm using the term in the general sense of the totality of all the installed pluming and heating components). Then there is another reg 8(1) the gist of which prohibits the alteration of a building so that the gas installation ends up as if it were wrongly installed.

Heating boilers and water heaters are classed as separate entities as far as gas fitting regulations are concerned.

A water heater is capable of putting 50C rise on the water going through it and certainly 40C reasonable of flow rates. If the input water temp go much above the 20C max it is intended for there will be substantial kettling even on a new appliance. In ordinary circumstances the appliance is probably quite near to kettling.

Now I know that there is no O/H cut out on the appliance I am genuinely concerned for its use. Although previously I was only stating the 'safe/establishment' line. If you want to do something to buck the system why not do some kitchen electrics?

[Doctor Evil]

Richard, there is no point. Why are you alive? Why are you here? Keep asking why? Then go back to the clinic.

[Doctor Evil]

Wrongly installed is open to question. In this case I would say it is installed correctly and well within safety limits if a overheat pipe stat is fitted and the pump flow was improved. In safety terms it is safe. No one, who knows his stuff, would say otherwise.

A boiler is termed a "water heater". The term boiler is being dropped - a corgi exam question.

A multi-point heats "water", whether fresh coming in from the street, or a tank, or in a loop - water. The only consideration is gas safety aspect. THAT'S ALL. Put a overheat pipe stat on the flow and it is clearly safe, and the installer has not touched the gas aspect of the multi-point either.

To have 50C temp rise the flowrate though the heat exchanger would have to be very slow. The average multi-point only give 10 litres/min flowrate at best @ 35C temp rise. Raise the flowrate, via a pump and temp rise narrows to 20, 25C.

On what do you base this? In the USA many multi-points have solar pre-heat. This is an unvented cylinder, heated by a solar panel on the "inlet" to a multi-point. So in that case water at 20.30, 40, 50C may go through the multi-point, although the multi-points tend to have outlet temp control by modulating the burner. They don't suffer kettling.

The ketting in this case is clearly scale, and a low flow through the appliance. Sort those and kettling will disappear. Put a high temp limit pipe stat on the flow and safety issues are eliminated. It is open vented and has a clear line to the atmosphere for safety reasons, so no problem there.

And as we all know that is bollocks too.

[Egremont]

. Well, on the face of it the above indeed appears to invalidate the 'proposed' installation.

RE Kettling, to be honest, you seem to be stuck in the starting blocks with the kettling!. I said in the OP that the 'higher' input water temp, with the

30C temp rise and limescale were part of the problem (which could almost have been predicted). But moving on, this can be addressed - for instance by increasing the flow of water. Double flow (say) = half temp rise = less or no kettling. You must know this, but it hasn't registered in your replies!. Limescale removal and boiler silencer etc can be thrown in as well. I would have thought his should work and, going on your figures, the boiler should be able to produce water at 70C..

RE cut-out, obviously it would be better if this boiler has a built in temperature cut-out, regardless of it's application. A negative point for the boiler. But, like with old cars, isn't there is a principle that you're not obliged to ditch the model you have and get a new (safer) version before the old one reaches the end of it's natural life?. I'm not convinced that the new usage profile (given limited CH needs and use of Thermal Store) is particularly worrysome, and at least with the changes measures would have been put in place (that weren't there before) to compensate this shortcoming. That said, it seems that one way or another this installation will not be acceptable to the powers-that-be, and the Thorn may be at the end of it's life and heading for a skip anyway.

As for doing kitchen electrics to buck the system, well I already did that!. When I found out about part P early last year I extended much of the electrics in the house, including the kitrchen.

Egremont.

[Doctor Evil]

Yep.

If you think it has a few more years and you can't afford the new condensing boiler yet, put a pipe stat on the flow, set to 95C. This will then cut out the pump, and hence the gas to the burner.

Irrespective of what any regs say. It is safe.

[Egremont]

The 'definitions' section of the 1998 SI states "Gas water heater includes a gas-fired central heatiung boiler", so I don't see how the above reconciles with this as, as far as the regs go, what goes for one goes for both?.

Egremont.

[Doctor Drivel]

Exactly. From safety point of view, your multi-point, as long as there is a high limit pipe stat on the flow cutting out the pump, is perfectly safe. The fact is, it is safer than when it was connected up to the cold water mains. It is operating in a far more stable lower pressure environment, which promotes longevity.

[Doctor Drivel]

I was talking today with three corgi men. I thought I would test them. I brought up the legality of this multi-point heating the thermal store. One immediately said without thinking, "I would condemn it". The other two said it sounds safe, so couldn't see a problem. Eventually all three said they would pass it, as the appliance we not touched and is still in its orgianal flue, gas syupply and and location, and it does not contravene safety, and is clearly not unsafe with the high limit pipe stat fitted.

One clearly said, it is the safety aspect of an installation that they look at, not what the makers recommend, adding that they have to use professional judgement. At least some of them are objective enough.

[Dave Plowman (News)]

Of course they were since you'd take away their trade discount on elbows if they dared to disagree.

Bet they had a good laugh after they left your counter.

Wonder if your boss knows how you waste his time?