Evening - After 23 years our boiler although not dead, is nearing the end of it's life. It's what I would call a standard boiler as we have a hot water storage tank. I thought if were going for a new boiler, why heat up water we might not use, so we'll go for a Combi (Instant) boiler instead. Got a quote for two different types of Combi condensing boiler by a local plumber (30kw) 5 year parts and labour. Temp stats on nearly all the rads, flush out blah blah blah for £2200 inc vat.

BUT.... one of my mates whose guidence I respect, is saying that I shouldn't get a combi as I won't get fast flowing hot water and, if someone is having a shower and a tap is turned on elsewhere then the pressure will drop. It could take half an hour to run a bath as you have to put the tap quarter/half turned so that the water is flowing slowly through the boiler in order to get water the temperature of 'Lava' for my wife & daughter.

It's natural for people who have a combi to say they love it etc and the same for a std boiler as they will say that system is the best. House stats: 4 bed, 2 showers, 1 bath, 4 sinks.

It gets a bit more complicated as well, as the two showers are currently gravity fed and you have to run around to get wet -I'm told with a combi at mains pressure (which is very high into the house) this would make the showers much better.

So people, what do I do ? do we have any plumbers in the house that can offer more help?

Thank you.

Your mate is correct about Combi's, ours is a typical 3 bedroom with 2 wc's, 1 shower and kitchen sink. if I turn on the hot tap while my wife is showering she shouts as it loses control and flow. Ours is a 28kW and most important to you is the 'Domestic Hot Water Flow', again ours is 10 litres/minute for a 30 degrees C rise. If you can better that figure with the new boiler you will have more of a chance.

I personally think it may not be for you but If you and your family understand and use it as such it does make a brilliant shower with the added pressure, ours is like a jetwash You just have to change your ways a little and be aware of others who may be showering.

The pressure can also be affected by flushing the loo if the plumber does'nt balance the system correctly.

Last edited by EYorkshire on 7th Jan 2012 5:55 pm. Edited 1 time in total

Keep the hot tank and airing cupboard.
A new condensor boiler should save you plenty on fuel costs. the exhaust fumes are barely warm so much less heat lost through the flue.
However my brother in law fits boilers and say that they dont last as long as old style boilers so much of your savings are lost in earlier replacement.
Make sure the new boiler has a quality heat exchange this is what fails early.


tip. sell your van use the cash to upgrade your boiler and insulation. smiles ALL round. With the money you save you will be affording wonderful foreign holidays At work
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Another vote here for a Condensing Boiler, we had a Combe Boiler years ago, never again.
Regarding the comments made by a highly regarded member regarding the Heat Exchangers being the weak point, I have only last week found out that if you have a Water Softener this lowers the choice of Boilers you can have, some components in today's boilers are not compatible with softened water

We have a condensing combi, excellent hot water and as EY states like a jet wash.
However, if we need a sink of hot water in the kitchen, we run to waste, around two to three gallons of water before it is hot enough to fill the sink. The combi is in the garage and the furthest point from the kitchen, fortunately no meter, so we don't pay, otherwise the boiler would be somewhere else.
Our cold pressure is very high so we see no effect from loo flushing, tun on another hot tap, however, and it goes cold.
There are some combi boilers now that have an instant hot water facility, keeping the hot water in the pipes up too temperature rather than a tank.

Last edited by taztastic on 7th Jan 2012 6:09 pm. Edited 1 time in total

ad210358 wrote:

Another vote here for a Condensing Boiler, we had a Combe Boiler years ago, never again.
Regarding the comments made by a highly regarded member regarding the Heat Exchangers being the weak point, I have only last week found out that if you have a Water Softener this lowers the choice of Boilers you can have, some components in today's boilers are not compatible with softened water

Look at a solar thermal system aswell

Basically use the sun to heat up the water, so instead of the new boiler heating it up from 2c it's heating it up from 25c so your saving the cost of the boiler heating it up a extra 23c

I am sure you can get a storage tank for a comi which makes it 100% better so you can run 2x taps at the same time

The exchanger weak point is due to the condensation produced is slightly acid

Worcestershire Bosch are highly recommended ones, though there is cheaper brands that offer an extra 2 years warranty

Yes, Combi boilers are now 'condensing' as well to improve efficiency. In fact the efficiency comes from the heating up stage only so a combi can be more efficient than a system or vented boiler.

Last edited by EYorkshire on 7th Jan 2012 6:21 pm. Edited 1 time in total

It is now illegal to fit a combi boiler - unless it is a Condensing boiler

The fitter can be sent to prison!!!!! BG engineer and a plumber told me that little fact....  2002 Honda VFR800
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taztastic wrote:

ad210358 wrote:

Another vote here for a Condensing Boiler, we had a Combe Boiler years ago, never again.
Regarding the comments made by a highly regarded member regarding the Heat Exchangers being the weak point, I have only last week found out that if you have a Water Softener this lowers the choice of Boilers you can have, some components in today's boilers are not compatible with softened water

Condensing is a technology used in combi boilers?

All boilers are of the Condensing type now, but you have to decide if you want the Combi system with hot water on demand or the standard system with a storage tank.

If you have the standard system with the storage tank at least you have the back up of the immersion heater should the boiler go down

We got a kettle if ours go down

NB: ALL new gas boilers (& oil I guess) are condensing as it is the only way they can achieve the efficiency ratings required under current regs. It is the condense drain off which is acidic. Must drain in to foul water system OR into separate special soakaway. 10MY (Sept 09) TD4 HSE Auto in Stornoway Grey (Now Gone)

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Also the fitting of Thermostic Rad Valves is now compulsary when you fit a new boiler, also notifying the local council that a new boiler has been installed so that it can be logged for the goverments emissions targets, which incurs a draconian fine if you fail to do so and some councils impose a charge of up to £350 for the honour.