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Original poster

Does anyone know anything about combi boilers and just why i can't have one? just th topic for a sunny Sunday I know.

46 replies

oranges · 19/04/2009 16:14

We have an ancient hot water cyclinder and boiler combo that is forever breaking down, and want it replaced.

The plumber who gave a quote said I'd still have to have the cylinder and boiler, as I have two bathrooms (one with a bath and an en suite shower room).

I cant see why that's correct. My parents have a combi boiler with a much bigger house and as many bathrooms. Is it really not possible? It would be significantly cheaper than having a separate cylinder, and save loads of space.

OP posts:

redshoes · 20/04/2009 20:55

We have 3 bathrooms and we are looking at getting a Worcester Bosch Condensing combi. Look on their site; we also looked at vaillant who also do a very powerful one. We are prepared for not all showering etc at the same time for the joy of hot water at any time.

lalalonglegs · 20/04/2009 21:11

It's not a question of not showering at the same time; it's a question of making sure that no one fills the kettle/brushes their teeth/turns on the dishwasher or washing machine/waters the garden... I would never go back to a combi now that I have a Megaflo cylinder.

lalalonglegs · 20/04/2009 21:11

Meant that no one does any of those things while you are showering not never ever does those things...

Quattrocento · 20/04/2009 21:14

We were told we could not have a combi because of size of house. It's not just the number of bathrooms but the number of radiators... Get a second opinion (we did, and a third, all to no avail)

Dottoressa · 20/04/2009 21:17

I know nothing about how or why, but we had a combi boiler installed last year, and we have three bathrooms. DH is pleased with it; I've not noticed any difference between the combi and the tank that we had before...

Dottoressa · 20/04/2009 21:18

It's the Worcester Bosch one that Redshoes mentioned, according to DH!

We have quite a lot of radiators and a draughty house, but also have a separate ducted air heating system for the ground floor - so maybe that helps our combi?!

Lilymaid · 20/04/2009 21:20

We have two bathrooms (and a cloakroom) and have a combi boiler - presuming that is one without a hot water tank. We don't have a cold water tank in the loft either - all the water comes direct from the mains. We don't have a problem with two people having showers at the same time except when the boiler has just come on.

Quattrocento · 20/04/2009 21:20

Oh I never told you what we did as a solution - which you might think is barking ... but here goes

We have a boiler and hotwater tank which heats the water in the morning and evenings. This services all the radiators and the kitchen and downstairs loo and two of the bedrooms. Then we had a combi installed to service the main bathroom and two bedrooms so that there is always hot water somewhere. Bit OTT but cuts down the bills remarkably.

cazzybabs · 20/04/2009 21:25

We have a combu boiler...it doesn't like 2 showers being on at the same time...but that rarely happens anyway..our washing machine and diswasher cold fill anyway

lalalonglegs · 20/04/2009 21:35

We found that even when cold water was used, it reduced pressure available so shower went from reasonable flow to a trickle while that was being done. I suppose it all depends on your water pressure but I won't ever go back to a combi if I can find room for a tank somewhere.

Ponders · 20/04/2009 21:39

Ah, but when you have 4 or more grown-up-ish people in the house all wanting baths/showers/hairwashes in a short period of time, having a combi boiler means there is always enough hot water for all of them - just not all at once.

I love having a combi boiler & would not change

BigGitNotYourAverageBlokeDad · 20/04/2009 22:30

Yes but if you have a combi boiler unless you have very good water pressure you cannot have baths and showers at the same time as the pressure will reduce. we went from a water tank to a combi boiler and I really regret it now. I thinj your plumber is correct. If you get it wriong it is an exxpensive mistake to make as it is expensive to revert back.
Sounds like to me you need a mixture of electric showers and a hot water tank.

Ponders · 20/04/2009 22:37

Yes but electric showers are crap IME. We have a mains pressure shower on a combi boiler, it's fantastic, & if you form an orderly queue the reduced pressure is not an issue - people just wait their turn for bath or shower, no problem

Ponders · 20/04/2009 22:38

And you never run out of hot water, whenever anyone needs some.

BigGitNotYourAverageBlokeDad · 20/04/2009 22:43

You know you can put an electic pump on an electric shower. On my shower it says it can take up to 12bar.
Not tried it though so if someone could let me know please get in touch.

Fizzylemonade · 20/04/2009 23:02

Ok, I have a combi boiler and 2 bathrooms BUT the hot water pressure isn't great but then we don't have showers at the same time and having hot water whenever I want it outweighs the flow issue (especially good when ds1 was sick all down himself at 3am and I could bath him in nice warm water)

My worcester bosch combi doesn't have a flow rate adjuster which I have been told hinders my boiler.

So in winter when the cold water comes into the boiler and it heats it, it struggles to heat it quickly so the flow is slower than in summer. But not so bad that you can't shower etc. In summer it feels like a power shower and in winter a normal shower.

So if you can find a combi boiler which allows you to adjust the flow rate for winter use you are onto a winner.

Hope this clears things up.

CarGirl · 22/04/2009 19:56

Fizzylemonade we've got a bog standard electric shower and that the problem we have for the same reason but it's far more expensive to run than a shower of a combi.

Dale09 · 22/11/2014 12:12

Help or advice needed,my combi boiler works fine with the heating and hot water,but as soon as I turn my cold water tap on when the hot tap is on ,the boiler cuts off so I only have cold water,this also causes me not to be able to use shower aswell,any thoughts thanks dale.

WantToGoingTo · 22/11/2014 13:52

We have just had a new combi condensing boiler installed, in place of water tank and back boiler. We have an electric shower. The thing with electric showers is that they work fine with combi boilers and are not affected by pressure etc. We also have an over-bath shower with a pressure pull thing (you know on the tap that you pull up). In order to use this with new boiler we would need to have fitted a pressure/pump/switch thing (fail to remember exact name of it) which would be £65+ VAT, because if not fitted then there would be very little pressure and if anything else was on at time of using the shower it would fluctuate from boiling to freezing. E.g. if you have washing machine on, another bathroom in use - would not get a constant temperature. This may be why they said to you you couldn't have combi boiler if you don't have electric shower? I think you could, but either by installing the pressure switch thing we were told about, or by changing to electric showers. We have a bathroom and a cloakroom, with electric shower, and that works fine.

WantToGoingTo · 22/11/2014 13:54

Also our boiler is a worcestor bosch one too

PigletJohn · 22/11/2014 15:29

You say you have two bathrooms

how many people are likely to be in the house at the same time and running taps/flushing WCs/running washing machines/having showers/running baths?
Fill a bucket at the cold tap at the kitchen sink, time it, calculate how many litres per minute you get (and at the utility room cold tap and the garden tap, if you have them). Calculate how many litres per minute you get (anyone quoting for a new boiler should have done this, and more).
Out of interest, see how many litres per minute you get at the hot bath tap. Next time you have a bath, see how long it takes to fill.

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