New boiler installation advice please

dazwood

Hi All,

Thank you for reading the post and your advice is very much appreciated. Our baxi broken down. We have standard system. cylinder and tank in the loft and microbore system. 3 bed house, 2 bathrooms and 2 showers with water flow between 16-18 l per min.

I had few quotes saying convert to combi and some saying leave the same system.

My issue if i convert can i run two showers at the same time or can i run a shower and other appliance at the same time with the water flow we have.

Where our boiler location we can only fit almost two models Baxi EcoBlue Advance Combi 40 or ideal vouge 40 can not fit bosch because of the service clearance requirement of 60 cm to wall (our utility room from wall to wall is 85 cm). Most the engineers said we can move the boiler to where is the cylinder and run gas pipe outside but i said i would rather leave the same place the boiler and not run pipe outside the wall and use all the free space when we move the cylinder as storage area instead.

Which boiler is better and shall i convert to combi? And can we do powerflush for our microbore system some saying we can some saying do not do it?

Thanks very much for you help and advice.

Alex1983

Definitely get it power flushed and fit a go quality magnetic system filter.

You could fit a combi or leave as is, a combi isn't designed to supply more then 1 tap at a time but you are looking at 2 big boilers that probably have quite high flow rates so you may get away with it.

Browntoa

Megaflo tank in the loft and a single boiler perhaps ?

Will supply plenty of hot water on demand for both showers at the same time

Alex1983

That's what I'd do, unvented hot water and new boiler like your old one in a sealed pressurised system. I'd keep everything where it is now, boiler in utility and cyclinder in airing cupboard.

dazwood

Hi Alex,
From your experience with our flow rate can a shower and another tap been running at the same time and can we do powerflush for our microbore system? Thank you

MrBluesky_2

Yes MB can be flushed first 2 questions at http://www.kamco.co.uk/FAQs.html#Tricky

To be honest for the higher hot water consumption its sometimes best not to convert to combi although the combi boiler makers will say different but i speak from experience of correcting many installations.
Many will say their combi system in larger houses work well but they are often just about working and any decrease in the incoming water flow rate will have an adverse effect.

Personally i would keep the boiler in the utility and have a new hot water cylinder in the airing cupboard but Not a mains pressure unvented cylinder.

If you really want a mains unvented cylinder then your installer will be able to check the incoming water flow rates are suitable and adapt your system so your showers get flow priority.
Remember you may need a larger water service pipe from the water main to operate an unvented cylinder again a plumber can check on site.

Good luck,

Chrishazle

Our daughter had a combi boiler in her last house - a 3 bed mid terrace. Her way of getting her husband out of the shower was to turn the hot tap on in the kitchen, shower promptly went cold and husband got the hint!!

Last November our Baxi bit the dust, we replaced it with a condensing boiler (I think by law all new boilers must be condensing, not necessarily combi), we have a system like yours but normal copper pipe for the CH rather than microbore, and a good sized hot water tank. We can run 2 pumped showers simultaneously for a while, but have to be careful as the loft tank is small and the cold feed into it cannot keep up with the outflow when the shower/s run.

fezster

What kind of showers do you have? How many litres per minute do they produce? The largest domestic combi will give you about 17 l/min of hot water. A good overhead rain shower will use roughly about 15-20 l/min, half of which is the HW requirement. So assuming your mains can deliver the required volume of water, you'd be able to run two showers (or a shower and a tap).

Keep in mind that in winter, a combi will produce water at a lower temperature (or a lower flow rate) because it needs to heat the water from a lower temperature, so performance will degrade.

Alex1983

If your definitely going to be using 2 showers at the same time keep the hot water tank or convert to a unvented tank.