which boiler type?

[neil.c.allen]

Hi - I have a conventional heating system in my house (tanks in loft, storage cylinder 1st floor, shower and heating pumps etc.) and would like to replace this with a system only needing a boiler in the garage (no storage tanks, pumps, cylinders etc.) to provide heating and good water pressure. However, and this is the crux, I want to be able to supply 2 showers without any major pressure drop when both are on. Is this possible with any boiler products in the market? and if so do I have to replace all my pipes to cope with higher pressure? (I always thought combi boilers will always suffer a pressure drop and can only power 1 shower).

been trying to answer this for 6 months now ...

tx a lot!

[Doctor Drivel]

There are combi boilers around that can do two showers. The water mains has to be able to cope though.

Wall mounted Alpha CD50, Glow Worm Extramax HE

Floor mounted (ideal for a garage) Glow Worm Ultrapower Potterton Powermax Viessmann 333 Idea Istor Worcester-Bosch High Flow Gledhill Gulfstream ACV Heatmaster ...and a few other around...

Another approach is use a high flow multi-point for CH, the Rinnai or Andrews will do here and a smallish, cheapish CH system boiler.

Another is use two combis, one doing each shower. One does upstairs CH and the other the downstairs giving separate control of CH in time and temperature and cheap to run - very cost effective. They can be combined for only the bath fills, filling a bath pronto.

[:Jerry:]

If you don't mind luke-warm showers....

I don't know why you don't just change your name to "Two Combis"!...

[Doctor Drivel]

You are an idiot.

Why should I when my name is fab.

[The Natural Philosopher]

You are pretty much correct.

You don't say whether you are gas or oil..

In any case you really want a pressurised hot water tank - megaflow is the generic term - and a 'boilerhouse' boiler - thats one with no case on. Cheaper for this sort of installation.

I can't say for gas, but when I was speccing a similar (oil) system last month, the megaflo plus boiler house boiler was no more expensive than a big f*ck-off combi to drive two showers at considerably less flow rate.

And actually fitted in the available space pretty well.

IN our case we discovered that the existing boiler could be used with a megaflow tank, saving useful cash.

[Doctor Drivel]

Another without a clue. Gosh! The man if after constructive help and these come in with 2.5p worth of tripe.

[:Jerry:]

He also wants *real world* solutions, not marketing theory.

I would really like to ask the OP why he want to get rid of the tanks, given all the real world advantages they have, like emergency emersion heater in the HW tank, stored cold water should the water mains gets isolated etc.

[Doctor Drivel]

I agree and I gave a long list of products that will do him.

[:Jerry:]

No, you gave him a catalogue and marketing speak - as he will see if he bothers to do a search of this group on Google groups - you say the same thing each and every time.

[Doctor Drivel]

Yes. Read bacl. Get back when you get stuck.

[Ed Sirett]

Some of the FAQs below may give some background info. The diy wiki (must put the URL in the sig) can be very helpful.

The pressure drop will depend quite a bit on the layout of the pipe work and the nature and quality of the mains supply.

A combi boiler (say 37kW) could be the answer to this situation but there are other solutions.

A good installer will try to take into account the various factors, what you want, what is achievable, costs etc. eg. A 37kW boiler needs to be quite close to the gas meter. An unvented cylinder needs a good mains supply or you'll be disappointed. etc.etc.

[Doctor Drivel]

A stored water combi being one, which will really perform.

New on me. Size the pipe up right with a dedicated boiler pipe and no problems.

The same with any mains fed supply.

[The Natural Philosopher]

And a 37KW boiler may well cost a LOT more than a megaflo tank and keeping the current boiler.

[Doctor Drivel]

The OP wants to save space. Anew condensing boiler will be far cheaper to ruins too. A few weeks ago you said a thermal store is the same as an unvented cylinder - now he knows it all.