CW tank in loft - should it stay or go?

[scotster]

I have a CW tank in loft that supplies the tap in the Bathroom sink and bath. Originally it fed a boiler and HW system but that was stripped out.

I will be having a lot of plumbing work doing as part of an extension and I have a new combi boiler that will be the basis of the system.

Is there any reason I cannot keep the CW tank supplying the bath CW tap as it will keep the flow rate nice and high with the mains fed combi supplying just the just the hot?

I will have the bathroom sink switched over to CW mains fed as I don't like the fact we are brushing our teeth in water that might have dead spiders in.

Last question please. I will be fitting a mixer shower which will be fed by the combi. Is there any means to maximise the flow of that by for example having the CW feed to the mixer fed from the aformentioned CW tank as I want to do with the bath? Or is there some other cunning way??

Apart from fitting a traditional bolier and hot water tank!

OK....let me ask that question. Are there any boilers out there with similar flow rate performance to a traditional set up but you can get in a tall large cupboard in the kitchen. as you would a combi?

Thanks for your help.
Scott.

 

[muggles]

I have a new combi boiler that will be the basis of the system

Why? How many hot water outlets do you have, or rather how many will you have when the extension is complete? Who has advised that you should have a combi? They aren't the answer to everything, and it could be that it's not the best option for you anyway.

Is there any reason I cannot keep the CW tank supplying the bath CW tap as it will keep the flow rate nice and high with the mains fed combi supplying just the just the hot?

Well I suppose you could have it on a dedicated supply, but do you really need it? You will almost certainly use more hot than cold in a bath, and at worst the same amount, so having a high flow rate on the cold won't really achieve anything. It would also mean that you couldn't have a mixer tap as the high pressure hot would just force it's way back up the cold. My advice would be to switch everything to mains.

I will be fitting a mixer shower which will be fed by the combi. Is there any means to maximise the flow of that by for example having the CW feed to the mixer fed from the aformentioned CW tank as I want to do with the bath? Or is there some other cunning way??

Unbalanced pressures to showers are theoretically possible but entirely unnecessary. Buy yourself a shower valve designed to run off a combi and everything will be fine. I recommend a Mira Combiforce. If you're really worried about flow then have your plumber fit full-bore isolating valves on it (and everything else).

A good combi could give equal or better performance to your old low-pressure system, but you'll have to be prepared to spend the money to get a really good hot water flow rate...and of course your mains flow rate needs to be up to the job.

 

[scotster]

Thanks for the help.

The combi is a WB Greenstar 30CDi and mains flow is about 13l/min.

We needed it to fit in a cupboard as mentioned and there would probably have been a better choice but we decided in haste last winter when the old boiler went kaput in the middle of the cold snap.

I am willing to consider a new boiler type but only if absolutely required. Could I sell my old boiler second hand?

We have a smallish 4 bed semi with two bathrooms with two showers (one electric) and one bath and one downstairs toilet. So ..hot water outlets...4 sinks, 1 mixer shower, washing machine and dishwasher and teh current electric shower but that of course just takes a CW mains feed. Is 13l/min OK? The flow and/or combi is causing 'some issues' at the mo when we are trying to run too many (say two!) taps at once and this will probably only get more frustrating as the kids grow up.... Is this more likely to be the mains flow at fault or the combi?

Anyway - all your help welcome.

Decide in haste - repent at leisure.

Rgds, Scott.