Are digital showers compatible with combis?

[ashtons99]

I currently have a pumped Mira magna digital on a gravity system but due to a new combi boiler installation next month I'm obviously going to have to get rid of the pumped Mira.

I've looked at the Mira platinum digital and was on the point of ordering but there seems to be a lot of adverse comment about the performance of this shower on a combi with fluctuating flows and temp.

I would like to retain a digital for the simplicity of operation and plumbing but if I'm going to get something which isn't up to the job I will stick with a traditional mixer.

Has anyone any experience with these and any advice to help me get the right one.

 

[Dan Robinson]

Depends on the boiler.

The shower preheat functions won't work, but a fully modulating boiler will be fine.

You can't use the pumped version of the showers either.

 

[picasso]

Just done one of these where the combi could not match the digital shower so I left the cylinder in place just doing the shower and the combi doing the rest of the house.

 

[Dan Robinson]

Forgot to mention flow restrictors earlier

 

[muggles]

Don't expect to run a rain head off a combi, but a standard one will be fine - I've fitted loads of digital showers to combi boilers (mainly Aqualisa Visage)

 

[ashtons99]

This comes back to my boiler dilemma and the 2 differing size boilers I've been recommended. I know I'm somewhere between a Baxi 33kw and 40kw. So would a 40 be a better match for a digital shower in terms of flow and temp balance or would this present modulation problems if I'm "over boilered "

I'm interested in the comment about the pre heat and it not working, guessing that's something to do we the way hot water is delivered. It's a shame if it doesn't work as that's a feature we use on the magna

 

[muggles]

Both 33 and 40 kW versions will present modulation issues as Baxi have just about the worst modulation range of any boiler available on the market today, so unless you've got a very large house with only one bathroom you're going to find that they'll be really quite inefficient when running your heating

As for which power is best for a shower, it's a bit chicken-and-egg as you need to know what the boiler can produce in order to select a shower, but might want to know what your shower can make use of when choosing a boiler. There's little point choosing a boiler that will deliver 16 litres per minute if your shower will only accept 12l/min

You also need to know your incoming flow rate at 1.5 bar pressure. There's no point choosing a boiler that is going to be more powerful than your water main can cope with

 

[ashtons99]

I think I'm going to move away from the digital shower idea and go for a conventional mixer. Particularly if the preheat function won't work if plumbed to the combi as it was that and the ease of piping which were the main reasons with sticking with a digital.