advice on new boiler system please

p5x

I'm looking to replace my current combi boiler (Main 30HE) as it's getting on for 15+ years now. It's generally been ok but we've had the odd issue with it such as having to replace the PCB on it a couple of years ago. The main reason for wanting to change is due to it being unable to power 2 electric showers at once.

Would a bigger combi boiler be any better in this area or am I better looking at a system boiler?

I also have solar PV panels if this changes my options in any way? i've noticed people mentioning the iBoost system.

foxy-stoat

Not many, if any, combi boilers can handle 2 showers at once....just seem you mention electric showers....you mean electric digital showers.

I am just having an unvented cylinder installed with new boiler at the moment, which was my choice after a lot of research and questions fired at heating engineers.

If you have PV panels then they maybe able to help heat the cylinder if you get one with twin heating elements.

p5x

foxy-stoat wrote: »

Not many, if any, combi boilers can handle 2 showers at once....just seem you mention electric showers....you mean electric digital showers.

Yes, They are Mira Sport 10kw showers if that helps. Is it just the case of going with highest output boiler or is it not worth even looking at a combi to do this?

I am just having an unvented cylinder installed with new boiler at the moment, which was my choice after a lot of research and questions fired at heating engineers.

Just wondering which boiler/cylinder setup you've gone for?

thanks

ianto11

I'm a little confused �� surely an electric shower uses a cold water feed only....nothing from the combi ?

matelodave

If you've got two 10kw electric showers then it really doesn't matter what size of boiler you've got because the showers are fed from the cold water mains supply.

Are you wanting to replace these with showers fed from the gas boiler.

We need a bit of help here to understand what you are trying to acheive

p5x

Sorry for being thick, I presumed it was probably just because the current boiler couldn't keep up with the hot water demand when both showers are being used. Currently we can only use one shower at a time otherwise the both showers either go cold or the water reduces to a trickle in one of them. A similar thing happens of someone is in the shower and one or two taps are turned on/toilet flushes etc.

Hope that makes sense.

Mr.Generous

Two Mia 10.8 kw showers would be more likely to overload the electrical system than trouble the hot water. They consume (up to) 10,800 watts of electricity to heat mains cold water and provide a hot shower. If anything they are taking the strain off the combi as many owners have a thermostatic shower using water heated by the boiler, a much cheaper option BTW.

Low mains water pressure could be the problem, make sure the main stop tap (male rooster, swear filter gets me on this word) is fully open.

ianto11

p5x wrote: »

The main reason for wanting to change is due to it being unable to power 2 electric showers at once.
Would a bigger combi boiler be any better in this area or am I better looking at a system boiler?

Sounds more like you have an issue with the flow of the cold mains supply to your property.
Your electric showers supply instant hot water,no requirement on the combi, so a new combi is going to be no benefit..ditto a new system boiler, unless you intend to install a HW cylinder and swap out both showers

(Cross posted with. MrG about the mains )

grumpycrab

p5x wrote: »

Currently we can only use one [electric] shower at a time otherwise the both [electric] showers either go cold or the water reduces to a trickle in one of them. A similar thing happens of someone is in the shower and one or two taps are turned on/toilet flushes etc.

Yes, as you've now realised - nothing to do with your combi. If you take the shower heads off both showers and run them on coldest settings, you need to check that the cold water flow through both - at same time - is good.

p5x

Thanks for putting up with my ignorance.

It seems it is the water pressure that is low, the stoptap is fully open btw.

It has been like this ever since I can remember though so is there anything we can do improve this? It's not just for showers though, there is a noticeable reduction in pressure if 2-3 sinks are in use at once as well.

grumpycrab

I'm no plumber but there are a couple of ideas here (whether you have a cold water tank may be relevant!)
https://www.tradeplumbing.co.uk/how-to-increase-water-pressure-in-your-shower_ep_197-1.html/