New combi boiler or pressurised hot water cylinder?

[MarshaB]

We are wanting to instal a walk-in shower into our bathroom. We have been advised by two different plumbers, that due to poor pressure, our best long term options are either to replace our 2 year Potterton condensation boiler with a large combi-boiler, or to install a pressurised water heater (two different options provided). Both seem of similar cost and it is not clear to me which is the best option. I have heard a combi-boiler does not work well in large houses, but can be an economical option from heating bills perspective.

Our house is quite large and we have 4 toilets, a bathroom and a showeroom (electric shower). The only mains pressure water is in the kitchen. Eventually I would want to replace shower in the my showeroom.

I would be very grateful for practical advice on what direction to go in. Many thanks in advance.

 

[Agile]

Based solely on what you have told us neither is going to work properly.

However, I expect that you have not given us an insight to exactly what they propose to do.

If the mains flow is poor then neither will work. The solution is to fit a new water mains pipe to the house.

Tony

 

[holty]

guarantee the word accumulator will pop up.before looking at unvented id get the water pressure situation sorted.an unvented can still be utilised with your 2 year old boiler.it is unvented that was suggested and not thermal store.

 

[MarshaB]

Sorry - I was not clear. The external pressure is excellent - the problem is internal. Does that make it easier?

 

[Agile]

No, it does not explain the problem.

The usual problem is the FLOW rate into the house. Thats associated with PRESSURE but not the same thing and not interchangeable.

Tony

 

[holty]

you could have great pressure.yet the flow restricted.this confuses most people as they automatically think poor flow is due to having poor pressure.all this can be measured with a flow cup and water gauge.to give true working pressure and flow.wich is good practice by any plumber when turning up giving advice to what your system options are.like said it seems stupid ripping out a 2 year old boiler that could be used.

 

[Gasman77]

OP, Do you mean you have good pressure and flow at the kitchen sink tap but poor elsewhere in your house?

 

[bengasman]

Sounds like unvented cylinder. Must as I hate the contraptions, a pump would save you about £3000

 

[MarshaB]

Hi. They came and measured pressure last week and said it was fine coming into the house i.e. cold water at kitchen tap, but otherwise pressure pretty poor.

Plumbers have given me three options: Large combi-boiler; unvented megafloHE or Torrent open vented mains pressure thermal store. Problem is - they are quite difficult to work out real differences and pros/cons.

Another thought is if I just went for shower with pump - could I upgrade at late stage to combi-boiler, or would I need a new shower?? Would that be a better option?

Thanks so much for all your advice.

 

[bengasman]

Sounds like vented cylinder. Must as I hate the contraptions, a pump would save you about £3000

Edit:
Done it again, corrected now, but said "unvented " instead of vented.