Vented hot-water Cylinder

Daisy_Dumpling

Hi.

We need a new central heating system for our old house and our village isn't connected to gas, so we're on oil. I've spoken to our heating chappie about a combo boiler and he pulled a face. Instead he's suggested a vented cylinder, which will be placed in a cellar, and a new condensing boiler in the boiler house.

I've read up about this on line and it seems a reasonable choice, but I haven't come across any mention of it on the forum. Has anyone got any experience of this system please, and can they offer any opinions or advice?

Many thanks

Daisy

Gloomendoom

Until fairly recently, a vented hot water cylinder was pretty much the norm where a combi boiler wasn't used. The cylinder is usually installed as high as possible though.

We have the same system as suggested by your plumber except that the cylinder is in an upstairs bathroom, not in the cellar.

When our boiler dies, its replacement will be installed in the main house, not the boiler house, because currently the heat losses from the long pipe runs are considerable.
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Stevefromdonny

Nothing wrong with a vented cylinder - having a seperate system boiler and hot water tank means it'll be cheaper to repair when it goes wrong as the parts are available more widely. Some of the repairs you could do yourself (non-combustion related of course). A combi boiler is more tricky to repair.

However, the downside with a vented cylinder is that you need a header tank in the loft (ideally a couple of metres above the highest tap). A thermal store is a more modern solution to this. A thermal store is a super-insulated cylinder which can have numerous heat inputs (boiler, solar, electric) and numerous heat outputs (hot taps, radiators). Thermal stores are very expensive though (£1000+ for a good one)

macman

Ask your RGI why he doesn't recommend a combi. His margin may be higher on a vented cylinder-or it may be that (following a site inspection), a combi isn't suitable, because of pressure or flow rate issues, or the number of bathrooms. Subject to this, it's really a lifestyle choice as to whether you want hot water stored or on-demand.

ollski

Have you considered an unvented hot water cylinder and sealed heating system?, no tanks in the loft to pipe in and worry about and mains pressure hot water.

matelodave

I've had vented tanks, non-vented tanks and combis and my preference by far is a combi. Unlimited hot water, no tanks in the loft or anywhere else in the house, simpler plumbing etc. You only heat water when you need it rather than having a tank wasting energy as it gently cools.
The only downside is that you've got no hot water in the case of a boiler fault.

rockin_plumber

macman wrote: »

Ask your RGI why he doesn't recommend a combi. His margin may be higher on a vented cylinder-or it may be that (following a site inspection), a combi isn't suitable, because of pressure or flow rate issues, or the number of bathrooms. Subject to this, it's really a lifestyle choice as to whether you want hot water stored or on-demand.

Firstly... Why ask an RGI about an oil boiler?
I think you may fine it's OFTEC.

Secondly, any oil fired combi boilers I have dealt with are not the same as a gas combi which heat up the water on demand.
Any of the oil fired combi boilers I have dealt with, had a water store on the side of the boiler and it keeps this heated, much like a hot water cylinder.
So although they are labelled as a combi, in my opinion they aren't.

macman

OFTEC-point taken, thank you.
But a combi with a small storage tank, gas or oil, cannot be directly compared to a conventional vented cylinder-the amount of stored water is tiny, and is simply designed to avoid the delay in hot water at the taps which most combi's have.

rockin_plumber

macman wrote: »

OFTEC-point taken, thank you.
But a combi with a small storage tank, gas or oil, cannot be directly compared to a conventional vented cylinder-the amount of stored water is tiny, and is simply designed to avoid the delay in hot water at the taps which most combi's have.

As we only fit grant oil fired boilers I know that the stored water in them is not tiny, it is in the region of 33 litres.


If you have the room I would always recommend fitting a cylinder be it vented or unvented.


At least you can still have hot water via electrical means should the boiler fail.

Daisy_Dumpling

Thank you for your replies on this subject. We're going to go with his advice and fit a vented cylinder.

Thanks again:beer:

Daisy