New oil fired boiler Combi or Condensing?

beeswax_3

Hi

We have just moved and are no longer on mains gas. We have an oil fired boiler, in good working order but fairly old. We are considering getting a new more efficient boiler. I've read that the hot water pressure in a combi boiler is not so good. We have poor hot water pressure anyway with our current hot tank system - it is a chalet bungalow, hot water cylinder is on ground floor - but it is live-able with, I can't imagine a combi would make it any worse, it might even improve! Anyone have any experience of this?

We have electric showers so am I correct in thinking that a combi boiler wouldn't affect the pressure in an electric shower anyway - as it heats the water on the way through. To get a better pressure in the shower I think we would need to install a pump?

So, is it worth getting a combi or shall we just opt for a condensing?

Moneysava_wannaB

Have a look at http://www.sedbuk.com/cost.htm to compare cost of new boiler/money saved on condensing boiler

w50nky

We have a combi (non condensing) oil boiler around 7 years old which supplies our HW and heating. It is much better for a shower than than the 8Kw electric shower we had prior to fiting this thermostatic mira mixer shower to the HW from the boiler. It is not quite in the same league as a power shower though. As it is fed via mains water pressure your incoming cold water supply will indicate the likely flow you can expect. If your system is gravity fed, how does your incoming cold water pressure compare to your hot water pressure?

beeswax_3

The cold water mains pressure seems to be fine. So are you suggesting a combi boiler BUT change the electric showers to "mains" (sorry don't know the correct term) showers?

I understand what you mean, but I'm thinking the extra cost of changing the showers at the same time might be too prohibitive. It is certainly something to think on though, thanks.

w50nky

Sorry, I thougt that you were looking for a better flow rate than you are getting from your electric shower as you were suggesting adding a pump to an electric shower which would not work IMO. The electric shower can only heat the incoming water at a given rate, as can a combi/condensing I suppose. So forcing more water through by adding a pump would cause a temperature drop which you would compensate for by reducing the flow rate to increase the temperature!

If your mains pressure is good then turning on your hot water tap from a combi oil boiler should not cause too much pressure drop to your electric shower.

tanit

We just changed our heating from LPG which had an old back boiler system to an Oil Fired Condensing Boiler.
We live in a rural area which has tremendous water pressure and like you have an Electric Shower.
We were advised to keep the Electric shower which is independant and not affected by the central heating system.
We find the system okay but I think if you have a family - like Mum, Dad, and kids all going wanting the use of water at the same time it wouldnt be so good. There is only 2 of us and if one is using the kitchen tap and the other runs the bathroom tap the water to both taps drops off.
For us its not a problem but if you have family members it might be an idea to get the advice of a heating engineer who will explain the pros and cons.

Cardew

All boilers are now condensing boilers.

A combi heats hot water(for taps) directly, where a system(conventional) boiler heats a hot water tank.(both are condensing)

The disadvantage of combis is a limited flow of hot water -especially at this time of year -, although if you retain your electric shower that will not have such a big effect.