Combi Boiler advice

[Idris]

[quote="YYS4BOB"It is vital that the pipework is flushed out properly before the new boiler is fitted.[/quote]

Ah! That rings a bell! What I've been told is that modern boilers contain small-bore tubing, so it is vital that the system they are connected to is squeaky clean otherwise there is a very real danger that blockages (and consequent localised overheating?) will result. The problem is that older central heating systems do not take kindly to the power flush which involves elevated pressures and will often develop leaks as a result.

[YYS4BOB]

Heat exchangers and calorifiers are usually only 8mm tube these days. The alternative to power flushing is to use chemical cleaners, but this can be a long-winded process involving several fill & drain operations. As stated, combis run on sealed systems, usually 1 bar cold, 2 bar hot. If your old pipework is dodgy, it will be found out anyway at these pressures. Make sure a "Magnatec" is fitted to the system. Your plumber will explain why, and what it does.

[misterpop]

Hoorah..We had a Worcester fitted only last week and compared to the 12 year old Ravenheat that was in before.. ....Stop there....No comparison.....First off let me mention what a plumber told me last week at work..I work at B and Q on hardware...The small bore pipe that is still fitted on a lot of systems was fitted years ago when there was a drastic copper shortage .Thats what he told me and I am inclined to except that as a good enough reason....Next as we live in Manchester which has the best water in the world we dont fur up our pipes so a blockage has never been a problem as far as I know.....Now then ! I was monitoring our gas usage and have been for the last 4 years and I can tell you that since the new boiler was fitted consumption has indeed gone down by I would say 1/3rd....Not bad ....Now the old boiler would take twenty minuets to run a decent bath .The new Worcester runs it in four no problem......Lastly you will be glad to know our brand new Worcester boiler was supplied and fitted FREE yes FREE from Help Link.Apparently we where one of the last to qualify for a free one as I am very old and my other half is retired......

[motorman]

you will be glad to know our brand new Worcester boiler was supplied and fitted FREE yes FREE from Help Link.Apparently we where one of the last to qualify for a free one as I am very old and my other half is retired......

Nice one misterpop, never one to pass on a bargain I see!!!.....................Do you have Scottish Blood in you???

[tjlglass]

Bob we got a 3 bed semi with 7 rads and no shower as we always take and preference baths. Are you saying 30 is too much ? And what are the advantages/disadvantages ? Wish mine was free lol

[Idris]

....Next as we live in Manchester which has the best water in the world...

Doesn't it come from Wales?

[misterpop]

Wales?.No Hawswater in the lake district......People have comes thousands of miles to Manchester to drink the water apparetly.

Ours is also a 3 bed seven rad house..Go big is my advice.You can always turn down....

A little Irish maybe..Och hi the O'noo..

[YYS4BOB]

Bob we got a 3 bed semi with 7 rads and no shower as we always take and preference baths. Are you saying 30 is too much ? And what are the advantages/disadvantages ? Wish mine was free lol

If you don't want to go to too much trouble (removing cylinder/tanks etc.) You could go for a similar boiler to mine. This is a SYSTEM BOILER, not a combi. Your plumber will explain. Basically (depending if your old system is open or sealed) all you have to do is change the boiler, seal the system (this involves fitting a pressure vessel and filling loop), and fit a Magnatec. This can be done in a day by a couple of good fitters. This way you will have the same flow rate to your bath as you have now. Ref the Kw rating, Combis are based on domestic hot water output, and are range rated (adjustable) this may be why the rating appears high, as it is the maximum the boiler will run at.
The other thing to remember is that you may have to increase the size of gas supply to the boiler.

[nickjones]

It all sounds rather complicated to me, just buy another kettle Tim.

[tjlglass]

So Bob are you saying a 30 combi boiler might be dearer to run than the old 1970's boiler I have at present.