Replacement boiler - options?

housebuyer2

Hi

I have a few questions on heating system options that I was hoping you could help advise me on?

We are buying an extended 4 bed semi-detached house, with 3 bathrooms/showerooms. It currently has a gas back boiler (with gas fire front), which provides heating to (I think) 9 radiators and hot water to a bath and 4 sinks, whilst the 2 showers are electric. It has a hot water cylinder in an airing cupboard on the first floor and a water tank in the loft.

We would like to replace the back boiler and gas fire (for various different reasons) and Im just looking for some advice on the options available.

One option would be to take out the back boiler and fireplace and replace it with a new wall mounted condensing boiler:-
- Presumably the existing pipework and radiators would need flushing out – but should still be suitable for this type of boiler?
- What are the options for relocating this kind of boiler? We would like to put in a woodburner in the fireplace, so would like the boiler sited elsewhere – can it go in the loft or in the airing cupboard?
- We would like to change at least one of the electric showers to a mains pressure mixer shower – presumably this boiler will be suitable for that?
- How does the timer work for these boilers? Can I set different times for hot water and heating? Will there always be some hotwater available for filling a sink?

The other option would be to take out the back boiler and fireplace and replace it with a new Combi condensing boiler:-
- Would this provide enough hot water and heating for a house this size?
- Would it be able to support the conversion of at least one of the electric showers into a mains pressure mixer?
- We are planning to start a family, so anticipate high future demand on hot water, so a combi may not be most suitable?
- What are the options for relocating this kind of boiler?

Would really appreciate any thoughts – I understand its all going to be very general given that people cant see the house – but my understanding is currently very basic, so would be great to get a proper grasp of my options (obviously once we move in we can get a plumber/heating engineer out to give us the details).

Thanks

housebuyer2

Thanks for the reply, how big is your house? Also do you mind me asking what the ballpark cost of that kind of work was? Did you require any new pipes or radiators as a result of moving to a more pressurised system?

Thanks

A.Penny.Saved

Combination boilers heat hot water as required so a timer for hot water is not needed. They cannot usually provide hot water and heat at the same time. Higher end ones might, American boilers for their larger houses can often do hot water and heating at the same time.

Combi boilers come in different power ratings and for larger hot water demands a higher power model might be required. Remember to over specify so that future demands can be met and extremely cold weather accommodated.

As stated previously, a combi is often put in an airing cupboard, replacing a hot water tank.

Canucklehead

OP: lots of excellent advice @ HHIC website. Cost will be dependent on the standard of the specification and your location in the UK.

southcoastrgi

A.Penny.Saved wrote: »

Combination boilers heat hot water as required so a timer for hot water is not needed. They cannot usually provide hot water and heat at the same time. Higher end ones might, American boilers for their larger houses can often do hot water and heating at the same time.

Combi boilers come in different power ratings and for larger hot water demands a higher power model might be required. Remember to over specify so that future demands can be met and extremely cold weather accommodated.

As stated previously, a combi is often put in an airing cupboard, replacing a hot water tank.

A combi won't heat hot water & heating at the same time, with the amount of hot water you require now or in the future i wouldn't go for a combi anyway, it really depends how much pressure & flow rate you have on your incoming mains supply, if it's good then an unvented cylinder will give you all the hot water you will require without roof tanks or pumps & a conventional boiler (either open vented of sealed system), however if your supply isn't that good then a conventional boiler (either open vented or sealed system) with a normal cylinder & possibly a pump for the showers.

Leif

A combi can go most places. Mine is in the kitchen wall, near the gas inlet. It can go in the airing cupboard, or in the loft, although it is less accessible. There are threads here about loft mounted combis. Hot water is almost instant in the kitchen as the hot water tap is 2m away from the boiler. Hot water in the bathroom is not instant, you have to run a tap some time, which for a bath is not a problem since you want to mix in cold water anyway. You need a minimum water pressure for a combi. I have a stove too, which means if the electric goes down, there is still one room heated.

DHSTom

If you are thinking of going for a combi boiler, I would think you would need to opt for a powerful combi boiler which can handle higher flow rate and heat outputs due to your property size and larger requirement for hot water .

Maybe the Worcester 30CDi or 37CDi or the Vaillant EcoTec Plus 831 or 837 ? Direct Heating Supplies stock a broad range,

unclebulgaria

Before you talk yourself into a combi please make sure you have your incoming water pressure/flow checked as this is crucial to any size property being suitable for this type of boiler.
KeithG has already hit the nail on the head, a combi sounds like it wouldn't manage your future requirements or what you have right now anyway.
CH has given you a good link too, there are loads of sites giving advice on boiler options.
Remember that a combi relies on all of its hot water output from the incoming mains water so operating two or more taps at the same time will cause problems unless you have fantastic mains water pressure.
Unvented cylinder for your hot water sounds like it would suit you best, just make sure that whoever installs it is correctly qualified to do so and holds a current unvented certificate and that they notify its installation. Its siting is also critical as these cylinders when full can weigh a lot so sticking one in a loft can cause later issues for your ceilings.
If you go for a conventional condensing boiler or system boiler remember that higher KW need more gas so even these boilers may require a gas pipe upgrade.

p.s. dont over specify any combi unless you have phenomenal water pressure/flow rate and really want to take advantage of it, a small combi will manage a lot of rads quite easily but its the hot water that needs the higher KW's.