Advice on electric boiler options

[Tr1pp]

Hi all,

Im going to be overhauling my bathroom soon(ish) with a new sink, toilet, bath, tiles the LOT! and see this as a perfect time to look into upgrading my existing hot water cylinder and maybe improving the pressure of the upstairs hot and cold.

The situation:
I live in a split level flat with one bathroom. I have a small vented hot water cylinder (which is VERY OLD about 20+ years old) which is supplied by the header tank just above it. the pressure to the bathroom taps is not too good partly due to the header tank being at head hight in the airing cupboard as I dont have a loft. the down stairs hot water also isnt up to scratch.

Our shower needs are met by a 9.5kw electric shower.

The mains pressure is alright but not amazing, havent measured the flow or pressure yet but I am able to put my thumb on the end of the tap and with a bit of force stop the flow...

The heating is all electric so no need to worry about that and only me and my g/f live in the property


The requirement:
I am wanting to replace the electric shower with a mixer shower ideally and want enough pressure to give me a more powerful shower It would also be nice if the taps in the bathroom had a bit more oomph also but the shower is priority. Hopefully this will reduce the the electricity bills a bit due to a more efficient boiler and no more electric shower


From what I can make out I have 3 options

1) Electric Combi boiler - not sure about this as why remove an electric shower just to put in an electric combi + this seems to be the most expensive option by far

2) replace the cylinder and header for a bigger header and vented cylinder and add a pump into the circuit (1.5, 2, 3 bar? im not sure what would be suitable)

3) get an unvented system - which would do away with the need for a header tank altogether however I would need to replace the current 15mm mains water pipe for 22mm and still might not have enough flow / pressure into the cylinder without an inline pump.

I need advice! Ideally I want the cheapest (to install and to run) and simplest option though I know the two arent always mutually exclusive in this situation, so the cheapest would be the best.

Thanks

 

[Tr1pp]

come on guys, im really hoping for some solid advice on this

Thanks

 

[theheatinghelper]

the option id go for would be the cylinder, header tank and a pump, but it seems you wont have enough room for a header tank big enough to serve the pump , have a look at this its just another idea
http://www.elsonhotwater.co.uk/html/thermal-stores.htm

ive fitted electric combis and some require a 16mm feed to the unit run straight from the board and they will only give you the flow rate you have. eveb if its a 15l /min combi and youve only got 7l/min incoming then thats all u`ll get

you can buy electric showers with a small pump built into them , ive not fitted a lot of them but hes a look at one

http://www.plumbworld.co.uk/mira-elite-st-98kw-pumped-3303-747

good luck !!

 

[ServiceNumpty]

Start with taking measurements of the flow and pressure from your incoming mains, if it's poor forget the unvented and combi.

 

[Tr1pp]

thanks both, I will do some flow measurements tomorrow, pressure testing might take a bit longer as i dont have the tool for that...

@ theheatinghelper, thanks for the link, looks good. I was leaning towards upsizing my cylinder and header then adding a pump as you suggest. my airing cupboard is quite wide and I can fit a 50gallon header tank easy will just need to rearrange some shelves.

I do like the unvented system for its all in one tidyness but not sure if it would be more expensive to install (if my pressure and flow is up to scratch)

 

[Tr1pp]

Just done a quick check:

Flow rate is 12.5lpm (through 15mm pipe)
Pressure ...still to test

 

[hansthebear]

if you can stop the main with your thumb i would bet money the pressure/flow is inadequate for unvented or combi

 

[Dan Robinson]

You ain't seen my thumb .

 

[Tr1pp]

yeah ive come to the realisation that my mains pressure limits me to an vented cylinder with cold water storage - thats fine as it also appears to be a cheaper setup (the parts anyway)

one slight annoyance though, the CWS will be at the same height as the shower head so I will need to buy a negative head pump which doubles the price...oh well


ps: the existing cylinder is sat within a steel frame with the CWS sat ontop of the frame. This frame wont be big / wide enough if i got a bigger CWS or even cylinder. would a plumber build a new frame out of timbers to support the CWS above the cylinder?

Cheers