Swapping an electric for a CH supplied shower

TheGardener

When we moved into our house 10 years ago with 3 adolescents we inherited a decrepit, dribbling shower that died on us within a month. We swiftly had a new one fitted and it's been fine ever since. It never occurred to me that we should have looked at one powered by our combi-boiler - but for obvious reasons, I think I should have a look now. 
Can all combi's run showers or do I need some sort of tank? I'd love to just swap it out and replace it with a CH one but I suspect life is never that simple...? 

ariarnia

we had a boiler fed shower fitted when we did our bathroom at the start of this year. its a little more complicated than a streight swap because the electric shower only had a cold water feed and the new one needs both hot and cold from the boiler. 

it took the plumber maybe a couple of hours to actually run the pipes from the sink (which already has hot and cold) and fit. ours was on the same wall as the sink and the room was being platered and tiled so we had them in the wall so you can't see them now. so you need to think about where the pipes will run and the finished look but i dont think its a big job. i dont know if ALL types of combi boilers can run showers but if your boiler currently does hot water for the taps then i can't see you'd need anything like a water tank. 
 
i think its definitely worth doing both for the cost and the fact our water pressure is suddenly a lot better (and we got a shower with both the normal shower head and a 'rainfall' type shower head which is amazing and i'd definitely recommend it)

BUFF

Pretty much any combi should be able to provide some kind of shower.
The principal governing factors are the water supply flow rate to the boiler & how much heat the boiler can provide to the hot water outlet - you can have less water at a higher temperature rise or more water at a cooler temperature.
The other factor to consider is how many taps/showers that you may want to run at once - see previous answer.

Do you know what make/model your boiler is & what the supply flow rate to your house is (you can probably measure this yourself by running & measuring your kitchen tap)?

If you do go with a shower from the combi I would strongly recommend going with a thermostatic shower valve (or bath/shower mixer if over a bath).

QrizB

Is your electric shower over your bath? If so, a simple tap-connected shower might let you try it out before getting a plumber in?

macman

You can have a combi-fed shower i.e. not tank-fed) as long as the water pressure and flow rate from the combi are adequate. Is the shower-room near to the boiler, or on a higher floor? But remember that your current electric shower is cold feed only, from the rising main. To install a mixer shower from the combi, you  need to reinstate the hot feed from the boiler (which could already be there, but capped off,  if the previous shower was also fed from the combi).
So at the very least, you'll need to replace the shower unit, remove the shower circuit, redo the supply pipes, and retile. 
Unless the existing electric shower is coming to the end of it's life, or you were planning to redo the shower room anyway, then it's going to take you some years to recoup the cost in gas-powered hot water savings vs the capital cost of changing it.

TheGardener

@BUFF Valliant Eco-Tech Pro 28 - how do you find out or 'measure' a 'flow rate' ? We do seem to have pretty goo water pressure.

@QrizB Can you still even buy those push-on rubber hair shower things? Unfortunately, the shower is over the bath but not at the tap end

@macman - sadly no shower room, just shower over bath. Upstairs but not over the kitchen where the boiler is. 

MikeJXE

Easy enough to pick the feeds up under the bath and and re route to the other end, in fact that might even be where the feeds come into the bathroom, the difficult bit to to bury they pipes 

macman

You can measure the flow rate at the bath, since you'll be using the same supply for hot and cold as the bath. The hot supply will need to be teed off from the bath supply and bought to the shower end, if it's not already there.
The flow rate is normally the limiting factor, rather than water pressure, if you already have sufficient pressure to run a combi.
As suggested, try it out with a push on shower hose before you make a decision

BUFF

Your boiler is rated to provide 11.1 l/min at 35C rise.
Your installer may have noted what it actually achieved on his installation sheet (I know that mine did for my Worcester).
If you have a couple of measuring jugs etc. & a clock you could fill those for a minute from your kitchen cold tap (likely to be the tap with the highest flow rate) or the bath & total them as a rough estimate for what your incoming supply rate could be.

Given what you have said you could consider replacing your existing bath tap with a (preferably thermostatic) bath/shower mixer with an extra long hose - that would minimise installation cost/disruption.

TheGardener

BUFF said:

Your boiler is rated to provide 11.1 l/min at 35C rise.
Your installer may have noted what it actually achieved on his installation sheet (I know that mine did for my Worcester).
If you have a couple of measuring jugs etc. & a clock you could fill those for a minute from your kitchen cold tap (likely to be the tap with the highest flow rate) & total them as a rough estimate for what your incoming supply rate could be.

Given what you have said you could consider replacing your existing bath tap with a (preferably) thermostatic bath/shower mixer with an extra long hose - that would minimise installation cost/disruption.

Righty ho, We'll have a go at that then. Switching to a mixer tap with a shower hose might be the cheapest, least disruptive solution. 
 My only problem is that the window is at the tap end and extends a few inches over the bath so that might be a pain but its worth a shot. Thanks

BUFF

You can get shower hoses in excess of 3m long.
If you are lucky (& wish to) you can have both bsm & electric showers.