Combi's & Flow rates for showers

[stutheflu]

Hi,
Ive searched and searched to try and answer the question myself but still in a grey area.

Looking to have my conventional boiler with storage tank replaced with a combi; my main concern is getting a decent thermostatic shower experience. 3 bed semi, currently only 7 rads but will be increasing to 8. Looking at the Baxi Duotec 28HE with a stated hot water flow rate of 11.5 Ltrs/min. I know this will be sufficient for the central heating but will it give a decent shower; i'm happy to base this on showering alone with other appliances and taps turned off.

I wouldn't be able to afford the next kw rating up on a Baxi so have also been looking at Screw Fix's Biasi Riva Advance 32HE that spurts out 14L/min; this i'm sure will be a good shower??

Mains water pressure / flow seems good.

Thanks in advance for your advice / opinions.

Stu.

 

[moggridgeplumbing]

First check your mains flowrate ltr/min. Then check what flowrate you have coming out of your existing shower.(are you happy with that?)

If you convert over to a combi, the combi output is dependent on your mains flowrate so bear that in mind when deciding on the model you are choosing.

 

[stutheflu]

Hi thanks for your response, moggridge,

Although i haven't measured my mains flow rate, based on the flow & power out of the downstairs and upstairs cold tap I know this won't be a problem ... based on the fact that you virtually get a shower from the splash back when you do. The current shower insitu is a mixer and is pathetic, the pipes are hidden beneath the tiled wall, but will be ripping the bathroom out soon and will check the plumbing to as why the shower is so poor in comparison to the water pressure; but then i have heard that conventional boilers with hot water tank are poor.

My main concern is just say all is well with my mains pressure and plumbing, will a 28kh combi with a hot water output of 11.5 L/Min give a decent shower once i install a new thermostatic shower?
So maybe anyone that does have this set up can give me their feedback.

I did have a thermostatic shower in my last house run off a combi and was more than happy with it; but I just haven't a clue what power / flow rate the boiler was! It was a bigger house with more rads so i could presume it was bigger than a 28kw who knows & i'll never know now!

Much regards.

Stu.

 

[moggridgeplumbing]

I personally would not go for a Biasi just to get a greater flowrate for a cheaper price. 11.5ltr/min is sufficient for most people that have been used to gravity fed showers - which is the reason you have had poor flowrate from your existing shower.

I usually fit Worcester boilers and Baxi are good, but I've heard Viessmann are very good quality and competitively priced. I have not fitted one so cannot comment any further than what I've heard.

 

[kev25v6]

I had the Baxi Duotec 40HE fitted last year and its an excellent boiler. Very hot water and perfect for a very decent shower. Heats the house very quickly and has been a lot cheaper to run than our old Sime Friendly which was no where near as powerful. The 40 HE gives out 16L per min though. Id recommend one to anyone. I had a straight swap when it was installed and it cost 1200 all in.

 

[transam]

Ravenheat do a 42 kw = 17 litres at 35 deg rise , at reasonable money

fit a combi store with it up to 19 litres a min & free hot water some of the time !

worth a look maybe ???

 

[Scoob72]

So maybe anyone that does have this set up can give me their feedback.

I have a thermostatic shower running off my Baxi Platinum 28HE and it's more than powerful enough. Previously I had a 10.8KW electric shower and the shower running off the combi is much more powerful....though obviously not up to power shower standards. Assuming your flow rate is good enough, then I'd say go for it.