Boiler recommendation for hot water only

[Bodgit]

Hi,

I currenlty have 2 boilers in my house - one oil fired boiler for the heating and a LPG powered Chaffoteaux multipoint water heater connected to a HW cylinder for hot water only. I'm quite happy with the CH system but I want to change the HW system because:

- I want to move the boiler as we're converting the room in which it resides into a bedroom. - It currently feeds the HW cylinder via about 20m of unlagged pipe. - I think the cylinder is scaled up as it takes ages to heat the water and the boiler seems to quickly shut down to a very small flame.

So I'm looking for a recommendation. I would still like a HW cylinder.

TIA, Dave.

[Ed Sirett]

Multipoint water heaters are not connected to HW cylinders usually. Some photos or a very thorough description is needed.

[David Hansen]

On 17 Aug 2006 09:20:48 -0700 someone who may be "Bodgit" wrote this:-

Sounds like a very strange installation.

There is a boiler selection FAQ, which you will find references to on this group.

If the hot water cylinder really has scaled up then it sounds like it is a direct system. As well as replacing the boiler you need to look at the plumbing of the hot water system.

You might like to consider an indirect cylinder, perhaps with a coil for solar heating (which will provide around 50% of the annual hot water, if correctly sized). Unlike LPG the price of sunshine will not be going up in the future.

You might also like to go the whole hog, for example using wood burning stoves as well as solar to charge a thermal store.

[Bodgit]

Everything in this house is strange!

It's an indirect vented system. The boiler is a Chaffoteaux Corvec. The water is pumped round with a Grundfoss pump. It's wired up with a time switch and a cylinder stat in series such that when the cylinder gets up to temperature the pump switches off. The pump needs to be turned up to speed 2 or 3 to get enough flow through the boiler to get it to fire.

There used to be 2 radiators on this system but I've removed them and connected them to the CH system because they were never hot when I wanted them to be, and they probably cost a fortune to run.

What happens now is that when the pump starts the boiler fires and runs on full blast for a while (maybe 10 or 20 minutes), then I can hear a little kettling, then the flames reduce right down so they're just visible. It runs like this for 3 hours or so before the cylinder is up to temperature and it switches off.

This also sounds interesting although I'm not sure I can justify the cost at the mo. Can you recommend a supplier?

[Bodgit]

I've described the system to David Hansen above - I hope this is clear enough. I'm not sure photos will really help, as it's all a bit spread out!

[Andrew Gabriel]

Sounds like the hot water cylinder is scaled up, so you'll probably want to replace that. Why not add a new hot water cylinder to your other boiler? It will need some plumbing and controls changes.

[Gav]

i have an unvented direct cylinder for sale if it is any use to you, cost 470 new, sell for half price cash

[Bodgit]

That's what I thought. I do need to move the boiler soon though so I may as well replace the lot at the same time.

Looking around it seems that 12kW is about the smallest boiler you can buy and will set me back around =A3500 + flue. The new cylinder will be around =A3300. Does this sound right or is there something smaller I can get (I assume 12kW is overkill really).

[Andrew Gabriel]

I'm not clear. I was thinking you wanted to [re]move the H/W boiler. Or is it the oil fired C/H boiler you want to move? Which fuel do you prefer to use?

[David Hansen]

On 17 Aug 2006 14:38:15 -0700 someone who may be "Bodgit" wrote this:-

I am slightly confused about which boiler you wish to move and what you want to end up with.

On solar cylinders

is one place to start. These cylinders can be installed, but no connections made to the solar/wood burner coils. These connections can then be made subsequently.

[Bodgit]

Sorry for the confusion - I misunderstood your email (tired last night). You were suggesting that I scrap the LPG system & connect a HW cylinder to the oil boiler.

I suppose it's an option but it would be quite disruptive to run the new pipework etc. as the oil boiler is on the opposite side of the house to where I would like the cylinder. And I don't mind having 2 separate systems - at least if one boiler breaks down I've not lost HW and CH!

[Bodgit]

Thanks. I'll have a look!

Dave.