shower in winter on combi boiler - is it ok to restrict water flow & get hotter water

[Mrs Tara Plumbi]

As per title can anyone tell me the answer?

Mr TP (otherwise known as he who is never here) has told me that it is not good to restrict water flow on combis in this way.

But i am not clear on this - is it about how much water is restricted or about the length of time?

The combisave restricts water flow - for a very short time - so perhaps that doesn't matter.

I skimmed through this very complicated document a long time ago and i think it said all depending on the boiler it would be a very bad idea to restrict below 3 LPM - i guess I would still have a shower greater than 3 lpm.

: http://www.elementalsolutions.co.uk/downloads/combis and low flows.pdf "Combination Boilers and Low Flow Fittings." © Nick Grant; Elemental Solutions 2007.

(must add - because some of you guys are so sensitive - I meant I find this document difficult, I know many of you are trained in this and deal with this sort of info every day...)

But i have often wondered if you can imagine a woman like me standing naked in the shower, covered in soap
- in the winter do I still have to turn the shower on full and shower in tepid water?

To be fair - as i often tell people i have a Remeha i should tell you that this is not a problem but i have had this experience from other combis in the pat and you all know it is a common problem.

 

[armourer]

Re: shower in winter on combi boiler - is it ok to restrict water flow & get hotter w

I now have a picture of naked soapy Mrs TP.........Thanks for that. :cheesy:

To my mind why reduce the flow to the boiler?
If you reduce the flow too much you wont make the flow switch and the boiler wouldn't fire.
The boilers are self modulating meaning the burner is linked to the flow temperature.

I would of thought it would have been better to just not turn the taps on as much?

You should only ever have a problem if you have a very long pipe run and its in the depths of winter (so incoming mains is really cold).
Try lagging all of the hot pipework.

 

[boblydon]

Re: shower in winter on combi boiler - is it ok to restrict water flow & get hotter w

Hi Tara, nice thought about a seeing a naked woman in the shower covered in soap, also good to see you have an excellent boiler.

From what i would say is the slower the water is passing through the heat exchanger or the bigger the heat exchanger the hotter the water will be, all boilers would have a minimum flow rate to prevent damage to the secondary heat exchanger, or to prevent the main heat exchanger over heating and turning off.........if you compare it to the fault you would get when the secondary becomes partially blocked it would have the same effect boiler cycling on/off.

I always recommend the the largest heat output combi's for exactly that reason.

Chances are that be restricting the flow to much the flow sensor may not activate anyway.

Bob