Advice: new CH system

[Andrew Haylett]

I'm having a new CH/HW system installed from scratch (to replace a somewhat antique, expensive and broken warm air/gravity system). Our chosen plumber has recommended:

Vaillant Ecotec 630 condensing boiler Santon Premier Plus unvented pressurized cylinder

15 radiators for a 5-bed house.

He seems to be competent, but any comments would be appreciated. Is mains pressure HW the way to go? (We already have a CW tank in the loft, which would go.)

I am particularly interested in the safety and servicing requirements of unvented systems.

warnings, but is it partisan?

We already have a shower pump fitted in one of the bathrooms. Is this permitted under the bye-law that prevents pumping from mains pressure systems, or does that only apply to combi systems?

thanks, Andrew.

[Owain]

Mains pressure is good *if* your mains pressure and flow are adequate, and - of growing concern in some areas - you are confident about the continuity of the main supply. If mains pressure/flow is not adequate, stay away from mains pressure systems.

For a 5-bed house, is he just going to fit TRVs to all rads, as for that size of house some multiple zoning of rads could be useful.

There are alternatives, such as thermal stores / heat banks, which can provide mains pressure water but do not use a pressurised store, if this is a concern.

This does not affect the choice of a pressurised primary (radiator) circuit, which is usually recommended.

AIUI pump (a) shouldn't be needed, and (b) would have to go.

Owain

[Doctor Drivel]

Good boiler.

Bzzzt. Wrong. This what they can do.

him to fit an integrated heat bank (thermal store with a plate heat exchanger). This will outperform the unvented cylinder and no annual service charge. Unvented cylinders require an annual charge of £60-£100. If he says otherwise take no notce. That is £2,000 over 20 years for storing water.

No.

See above.

You can't have a pump on any mains pipe. Is the mains pressure and flow good? If so then go heat bank. They provide a wonderful buffer for the boiler and the CH circuit. You can have TRVs on all rads using a Grundfos Alpha pump too. No electric wall stat. Boiler cycling is elinminated.

[David Hansen]

On 11 Aug 2006 14:59:02 -0700 someone who may be "Andrew Haylett" wrote this:-

If installed and maintained properly they are reasonably safe. Not

100% safe, but nothing else is either.

Annual servicing costs money (and I suspect the costs will only ever go up) just to store some hot water. A nice little earner if one can get it.

I agree with the ticks and crosses at the bottom.

Were I doing what you are doing at the moment I would look very seriously at the Conus 502 supplied by multiple heat sources

[Dave Plowman (News)]

Poor advice. A programmable wall stat saves energy as well as making the house more comfortable.

[Doctor Drivel]

The idiot comes in again. Andrew is asking for advise, he doesn't need an senile amateur idiot to but in. Piss off loon. Go down the drop-in centre.

[Doctor Drivel]

This is a very clever design to maintain stratification within the cylinder. It is good for solar applications. I would go for heat bank (thermal store with a plate heat exchanger) with a more efficient plate. Range, Nu-Heat, DPS, etc do them. I would have a blending valve (UFH models) on the flow and return of the boiler to ensure condensing operation and swift reheat. A plate heat exchanger as opposed to a coil is far more efficient and delivers higher flows than a coil (that gas appliance guide does not mention plates being out of date). Also plate heat exchangers can operate at higher pressures, hence higher flows than unvented cylinders. Also have a Magnaclean filter on the CH return to the heat bank cylinder. This ensures no sludge build up.

[Dave Plowman (News)]

To the OP - dribble doesn't understand even the most basic electrics (like most poor plumbers' mates) so avoids them at all costs.

Anyone with any real world experience will agree that a programmable thermostat saves energy as well as making the house more comfortable.

[Doctor Drivel]

Fuck off idiot!

[Doctor Drivel]

He can always install an accumulator which gives mains pressure hot water in volume. One can be rigged up quite cheaply.

Yep. And each zone can go directly back to the heat bank cylinder which is a wonderful neutral point and CH buffer. Each zone with a Grundfos Alpha pump, TRVs on all rads and simple single stage time clock. A weather compensator can be used to float the temperature of the CH buffer in the store in line with the outside temperature promoting condensing efficiency. I would use a Glow Worm HXi boiler which is simple and made by Vaillant and cheaper too. Also have two cylinder stats to eliminate boiler cycling.

[Guy King]

The message from "Dave Plowman (News)" contains these words:

I wouldn't be without ours. Great thing, particularly like being able to set different temperatures for different times of day.

[Doctor Drivel]

Individual room control is usually best. A centralised stat may switch out the heating when some parts of the house are calling for heat.

[Andy Hall]

Given the space..... Unfortunately water, in the liquid phase, is not all that compressible.

[Doctor Drivel]

Matt, you need to put one in, to get rid of all those pumps.

[Guy King]

The message from "Doctor Drivel" contains these words:

We rarely shut any of our doors and it's a small house.

[Dave Plowman (News)]

So you are a foul mouthed plumbers mate who doesn't believe in saving energy? Of course you have a recent non-condensing boiler in your own hovel, so say no more.

[Dave Plowman (News)]

It might be if one used something more sophisticated than TRVs. But that would be beyond the likes of you.

Then you've installed it incorrectly - if an average sized house.

[Dave Plowman (News)]

Yup - which TRVs can't do. I reckon it saved its cost in my case within a year or so.

[Doctor Drivel]

Do reply to my posts. Fuck off idiot!

[Doctor Drivel]

Do reply to my posts. Fuck off idiot.