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[tonyappuk]

No OF, I made sure he replaced the old tank. Living in Hampshire we have very hard water and the heating coil gets badly scaled up quite quickly so I have replaced the tank several times. I still prefer the convenience of a tankful of hot water and a warm airing cupboard, and the condensing boiler, together with improved heating control, is more efficient. That is important these days with the high price of heating oil.
Tony

[oldfogy]

The main point of Combi & Condenser boilers is to avoid the storage and constant heating of hot water that is only required a few times a day and the Combi & Condenser boilers will give you instant hot water any way.

Basically as I see it is that you have minimised the benefit of any cost saving on fuel, tank replacement and wear-&-tear.

However, my only question is, Is this setup what the plumber did or is the hot water tank part of the manufacturers design with hot water tank time controls built-in to it's program?

[tonyappuk]

OF I agreed the design of the system with the plumber. There are motorised valves to control the feeds from the boiler to the hot tank and the radiators. These valves are controlled by the programmer which can be set to heat the tank and radiators separately at different times. The boiler only runs if the programmer allows it. The boiler pump only runs if either the tank thermostat or the room thermostat says it should and the boiler only heats the water to 55 degrees C to enable the condensing function to operate efficiently.

The tank heating is restricted to an hour or so in the morning so we all have hot water first thing and then it is allowed from about 8pm for an hour or two. With the improved lagging of modern hot water cylinders this lasts fine for us. Of course it can be over ridden if we run short.

In the Summer the radiator heating is switched off but we still heat water by oil which used to be cheaper than electric heating. With the recent rises in the cost of oil and electricity it is probably time for a new comparison to be made. Maybe the immersion heater would be cheaper now.

It may be that a combi set up would be a little bit cheaper to run but as I said at the beginning of this thread my experience of combi boilers to date is that the through flow is poor needing a long time to fill the bath etc. This could be overcome I suppose by fitting a much higher rated combi boiler than the recommended but that would raise the capital cost and maybe the running costs.

You pays your money and take your pick.
Tony

[oldfogy]

Yes many (20 years ago) we had a heating system where the hot water would take about 30+ minutes to fill a bath.
The problem there though was the layout design, because the hot water tank was on the same level as the bath and obviously very little header pressure as it was a combination tank.

But when I moved into my own house and designed the layout of the new heating system although nothing fancy but the cold water header tank in the loft and hot water tank on the first floor and with the bath and plumbed-in shower unit being down stairs the hot water pressure was truly amazing.
Obviously the header tank is the crucial point because that is where the pressure is gained from, from gravity of the water filling the hot water tank.

However, and back to Combi vs Condenser boilers.
For me it's difficult to decide but if I had to make a decision I would say that of the two is the most "cost effective" would be the Combi boiler, however the Condenser has a lower carbon footprint, but that comes at a price.

My only dislike with my 10 year old combi boiler compared to new units is the need to have a pilot light burning 24/7, where newer units and Condenser units do not have that as it's operated electronically on a as and when required basis.

My point being that with a Combi or Condenser boiler you always have instant hot water without the need for a tank as and when you required, as I said earlier, by introducing a hot water cylinder you have done away with any cost saving and benefits of either a Combi or Condenser boiler.

Obviously it's your boiler and you know which type it is, but if you had not said it was a Condenser boiler, then by your initial description I would have been inclined to doubt what you had said and suggested you check it out, and next time "do not use that particular plumber"

[kitz]

>>> However, and back to Combi vs Condenser boilers.

Forgive me if I mis-understand cause what I know about plumbing you can probably write on the back of a postage stamp.

But I thought new boilers had to be condensing boilers - something to do with green do-dah and efficiency.

.....and combi-boilers were the ones that heated hot water + heating as and when required, therefore eliminating the need for any water tanks.

My old boiler was 'just a' combi-boiler...  the new boiler is a condensing combi boiler.

[oldfogy]

>> But I thought new boilers had to be condensing boilers
No, not really, it all comes down to cost.

Both types of boilers "basically work and do the same job as each other" but the difference is in how they do it.


>> something to do with green do-dah and efficiency.
Green vs Efficiency?
That is a tricky one, condensing boilers emit less carbons etc into the atmosphere, "but in actual fact cost more to run" than Combi boilers.

Quite a few housing organisations use condensing boilers simply so they can say they are using the latest up-to-date equipment that lowers the carbon footprint, this then helps in a BIG way when applying for government grants etc.

Truthfully, all this "carbon footprint" business is all a load of expensive hog-wash, of which you are the one paying for it.


Edit:
Text added

[tonyappuk]

Condensing boilers extract some of the waste heat out of the flue gases and are thus more efficient and cost less to run. The regulations say that

"# All gas-fired boilers fitted after the 1st April 2005 have to be condensing boilers. This applies to all brand new installations and those that are a boiler replacement.
# All oil-fired boilers fitted after the 1st April 2007 have to be condensing boilers and again this applies to new installations and replacement boilers."

so you don't have a choice between condensing or non-condensing anymore which I regret not liking bureaucratic interference in our lives but I have to say that I am pleased after three or four years with my new boiler how efficient it is.
Tony

[oldfogy]

All I can ask is that you study the Worcester Boiler sales literature and available equipment before you go believing everything that you may be told by someone who is not installing the equipment...........

http://www.worcester-bosch.co.uk/homeowner/products/gas-boilers

[tonyappuk]

Not to labour the point the latest Building Regulations say you can only fit non-condensing boilers in exceptional cases where, because of installation problems, it would be very difficult to fit a condensing boiler and this "relaxation" only applies in the case of replacement and only after a points assessment has been made! All a load of cobblers really but what we must all endure in this PC age. The Building Regs also require an "Approved Document L1 of the Building Regulations" for your boiler. Your installer should provide you with one of these, Kitz.
These are the same Buildings Regs that theoretically stop me wiring up an extension socket in my house in case I hurt myself or someone else. With a working life spent in broadcasting engineering that's silly but it illustrates the nanny state in all it's magnificence.
Tony