New boiler on old system

[Martin Wiseman]

Hi,

My mum's 30 year old gas boiler has gone bang. It might be repairable or it might not.

If it is not, the plumber wants to charge her £2000 for a week's work to replace the boiler and hot water cylinder and fit thermostatic valves on the bedroom radiators. He quotes "regulations" as the reason that he has to replace the cylinder and fit the thermostatic valves.

This sounds suspicious to me. I understand that the new boiler will have to be a condensing boiler, and I understand the general principle that replacement or additional items on the system have to meet the latest regulations, but I was sure that there was no requirement to replace working items while they continued to work.

Can anyone enlighten me as to the truth of the matter. Are there any technical or regulatory reasons why she can't just have a condensing boiler fitted at the present time and coupled to her old (slow recovery) hot water cylinder and radiators without thermostatic valves. (We realise that it won't work at it's maximum efficiency without further changes to the system, however that is not the issue).

Many thanks, Martin.

[Doctor Drivel]

The old boiler may have gravity DHW. Also it is best to fit a "Quick Recovery" cylinder, NOT a Part L. Insist on one. This will take all the boilers output and promote condensing. Also what make and model of boiler is he specifying?

Technically the old cylinder can stay, but it would be foolish to keep it. The TRVs have to be added.

[Martin Wiseman]

Hi,

No, it's fully pumped, either Y plan or W plan.

That I can understand.

On what grounds, technical or regulatory?

Thanks, Martin.

[Doctor Drivel]

Regulatory.

[Matt]

Utter Dribble

[Doctor Drivel]

thanks you for the solid contribution.

[Doctor Drivel]

[Malcolm]

Is that for a complete new installation, or even if you simply add a new rad to an existing system that currently uses a room stat

Malcolm

[Doctor Drivel]

New and boiler change - it is how they interpret the regs.

[Christian McArdle]

He is half right, half wrong.

When replacing the boiler, you WILL need to update the controls if they're not up to current standards. You WILL NOT need to replace the cylinder, although if the old one is in bad condition, poorly insulated or has a tiny coil, then it might be a good idea anyway.

By controls, you will need:

1. Separate temperature control of sleeping and living areas. This is most cheaply and commonly done with TRVs.
2. In a large house, separate timing control of sleeping and living areas. This is usually done by subzoning with zone valves, although electronically controlled TRVs can also be used.
3. Fully independent control of hot water and central heating.
4. Thermostat on the hot water cylinder.
5. Fully pumped circulation in both the radiator circuit and the hot water circuit.
6. Boiler interlock. When there is no call for heat, the boiler burner must entirely switch off and must not keep the primary water hot. This is usually done using a room thermostat or a flow switch.

Christian.

[Capitol]

Or alternatively, mend the old boiler. Much cheaper option.

Regards Capitol

[Doctor Drivel]

In a new system it ios cheaper to zone.

electronically

Or two boilers on separate systems.

[Dave Plowman (News)]

You can retain the room stat for that room, and obviously not fit TRVs in that room, while fitting them to all the other rads. And if fitting a new rad it would be crazy not to fit a TRV. However, fitting an extra rad will involve draining down, so it makes economic sense to fit TRVs to the other rooms (but not the one with the stat) at the same time and of course add inhibitor. TRVs should recover their cost quite quickly. But if you go down this route, use quality TRVs from a PM, etc. Shed ones tend to have a short life.

[Dave Plowman (News)]

My 30 year old system satisfies all these requirements already. And always has done.

[Doctor Drivel]

It hasn't been serviced for 18 years and he needs to take a mortgage to pay the gas bills.

[Dave Plowman (News)]

Why fiddle with something that works perfectly?

But once again I'd ask what you'd service on a heating system, since you plainly don't haven't a clue. Since you can't find it on a website.

I don't need a mortgage for anything, pet. Unlike you who seem to just wreck your relations plumbing for a 'living', I make enough money to pay all my bills as and when they become due.

But then your clinic bills must be high, very high.

[Doctor Drivel]

The senility is certainly taking hold.

The senility is certainly taking hold in big way.

..the Plowman man he calls me pet ..of inverted gender he must be set ..he gives us info we don't need to know ..down our throats he rams it so

..instictively you will spy ..in newsgroups with DIY ..attempting wisdom this fool will try

..the info's so poor tis clearly true ..so how does this garbage affect you?

..well take no heed of babble and drool ..as this one is a confirmed fool

..he marches around in CAT boots of yellow ..this strange brain damaged sort of fellow

..misadvice he has lots to say ..so don't give this yellow booted half-wit the time of day

[Dave Plowman (News)]

Ask the nurse for more medication. The 'poetry' fetish has started again.

Or ask the nurse to write it for you. Or anyone, really. Can't be worse than your efforts.

[Doctor Drivel]

Is this must be your sexual perversion nurse

[Lurch]

On Thu, 29 Sep 2005 10:12:24 +0100, "Doctor Drivel" scrawled:

???

Still knocking back the sherry in the early hours I see.