avice off a plumber please

[Phooey]

Hi, i am having my bathrooms revamped later this year so am at present deciding on what kit to put in. I really fancy a rain/drench shower head, but have been told by Porcelanosa that my combi-boiler will not have the 'flow' required to do the job properly. My boiler is a 10 year old Worcester-Bosch Highflow 400. Another plumber i spoken too says it should be fine? So, one person says yes, while another says no

Has anyone any experience of combining one of these shower heads with a combi? or are these more suited to systems with a pump. Am i right in thinking you can not add a pump to a combi system?

At present we just have an old Mira mixer which TBH is quite adequate, but had seen a few HansgroheAxor items which looked quite interesting.

Another question - would i benefit from upgrading my boiler? We are on a yearly maintenance plan with Worcester-Bosch at present.

Thanks

[Jazoli]

Yes you would benefit from upgrading your boiler, the new ones are incredibly efficient compared to a ten year old one, and quiet, and would run your choice of shower head easily

[Phooey]

Jazoli said:

Yes you would benefit from upgrading your boiler, the new ones are incredibly efficient compared to a ten year old one, and quiet, and would run your choice of shower head easily

Just had a look on the Worcester-Bosch website - looks like the highflow 550 is the most powerful at 25 litres per minute flow rate. I think mine is 18 litres per minute.

[andy43]

What you need to know is
1 - litres per minute of the shower head, and
2 - litres per minute of the boiler - working on a certain degrees temperature rise to supply shower-temp water bearing in mind it'll be mixed with your cold supply to a comfortable temp.
Or you may still find in cold weather with water at 5 degrees in your mains supply that the boiler still may not be able to cope. Flowrate alone isn't enough to work out whether a boiler is big enough.
This is where a good plumber is priceless (and no, I'm not one!).

[Ferg]

I'd do some flow tests.
It's important to bear in mind that the boiler may well be capable of providing 25 litres a minute, but it won't if you haven't got that coming in on the cold main. 25 l/min is not that common 'round our way.

[Phooey]

Sounds like there is obviously more to this flow rate than first thought then

I was reading through a couple of brochures - seems these *BIG* shower heads are not really recommended for combi's. Not a problem, there is still some nice *mid* size rain heads which are recommended for the combi - Mira do quite a nice one.
I will ask the plumber to confirm its suitability first though.

[dickymint]

Ferg said:

I'd do some flow tests.
It's important to bear in mind that the boiler may well be capable of providing 25 litres a minute, but it won't if you haven't got that coming in on the cold main. 25 l/min is not that common 'round our way.

Ferg: I know that "storage combis" exist. Is it possible/viable to add a storage tank to an existing combi and use a high pressure pump to the shower?