Combi Boiler vs System Boiler / ADVICE

Nuovashenron

Hey there!

I posted before about looking for advice to remove my electric system which is a water tank and boiler - they are 30 years old, and the space they take up in my small 2 bedroom apartment is too much.

I've looked into combi boilers, and it appears the OMC is fine with me doing this. However, I'm looking to not remove the bath when the bathroom is remodelled. I have heard that combo boilers are not great at all for baths so I was hesitant. But I am now learning of system boilers, as seen on this article here.

Ideally, I would love the instant hot water that can't run out as the combi provides - yet the ability to use multiple taps and fill a bath with no hassle like a system boiler would do.

My question is - what should I be looking into? is there any way to mix the system boilers advantages yet somehow have an on demand bath/shower?

Anything at all would be really helpful!

Nuovashenron

I forgot to mention - what is important is being able to use shower/bath, dishwasher, washing machine, etc at multiple times. Not that I'm looking to do exactly that, but in case a wash goes on and we want to shower or take a bath the boiler system can handle it 😅

10-10-20

Hi, did you see the highflow combi boilers with water storage and preheat?

https://www.worcester-bosch.ie/products/boilers/directory/greenstar-cdi-highflow

They deliver a rate of 20L or 25L at a difference of 40C (from the mains) per min. I'd like to think that would be sufficient for a bath? If not then you'll need to stick with a cylinder, I would think.

Nuovashenron

this is near perfect, and thank you for bringing this up!

however - I can only use electric systems, and this one is gas. My apartment building has no gas supply, everything is ran of electric.

would you have any other examples like this for electric? I can’t seem to find anything similar on google

Lenar3556

You have limited options with electricity as a heat source, because the available electricity supply within your apartment wont exceed about 10KW.

High powered gas or oil combi or system boilers would have outputs closer to 40KW. The link you provided is for gas boilers.

A hot water cylinder with electric immersion(s) is likely going to be the best solution. Maybe have a look at the possibility of relocating it or different sizes and shapes.

How is your space heating run? Storage heaters? Or is there an electric boiler which heats water filled radiators?

Nuovashenron

Currently, there are storage heaters that are being upgraded - there were super old, and we are upgrading to a more efficient and smart system. They are completely separate from the mains as they are just wired in therefore no water source.

So the only things that will require water/heated water is the shower/bath, dishwasher, washing machine and sink in bathroom and kitchen.

I have such limited space in the apartment and the current water tank is sitting directly above the old boiler in a small room beside the bathroom. If the water tank can be removed and a single combo boiler/storage boiler is possible this would greatly free up space and allow us to have a more modern system.

noodler

My.combi.fills.my.bath no problem albeit with a pump

ongarite

Can you take a photo of your current system because you are say it all electric water heating and then in last post say boiler & separate water tank. Boiler would be oil or gas

Nuovashenron

@ongarite system is currently obstructed so can’t take a photo just yet - however I can assure that I have no oil/gas bill and neither does any unit in apartment building. There is a boiler which is paid for and ran electrically and above it is a water tank

Lenar3556

https://www.boards.ie/discussion/comment/123316548#Comment_123316548

By boiler you perhaps mean hot water cylinder, with an integrated cold water storage tank directly above it. (combination cylinder)

These would be common in apartments and usually provide satisfactory performance.

In most cases there isn’t really a viable alternative.

Nuovashenron

ah yes this sounds more like it! However my water tank is not integrated but separate and it has been installed above the water heater - just a large plastic container.

They are both so massive and I could find a smaller alternative I could free up some space. And how they are situated it’s almost impossible to access for maintenance