condensing combi-boilers

  gibfish26 15:54 23 Jun 2008
Locked

hi all
thinking of changing our 20 year old gas boiler for a new combi,i believe its now government law that all new boilers must be condensing type,can anyone give advice on the best make of boilers to go for.at present when we turn tap on we waste about 2-3 litres before it runs hot,plus it burns a pilot light 24 seven,we live in a bungalow so our taps are only about 2-3metres from the boiler,but the hot water tank is in the cuboard in the hall on opposite side of house hence the waste of water.your experiences and comments will be much appreciated.thanks.
gibfish26

  wee eddie 16:47 23 Jun 2008

in a small household are frequently illusory unless it is used for the central heating as well. CBs only come into their own when they are at their optimum working temperature. If the Exhaust Pipe becomes cool, frequently, it can be dissolved by acid condensing from the fumes.

You will never get rid of the run off of the water between the Boiler and the Tap.

  BT 16:55 23 Jun 2008

You will find it much more economical than an old 20year old boiler. The modern boilers don't have a pilot light they use an electronic spark each time they fire up. With a Combi you don't usually have a hot water tank the hot water comes directly from the boiler on demand so if the new boiler is near your taps you may find the water is hot at the taps quicker.
As to makes, there are many good ones but we have found Vaillant one of the best, but not necessarily the cheapest.

  Binnacle 17:15 23 Jun 2008

Have a look here click here

  Ventad 17:44 23 Jun 2008

You need to get the right hot water output for the right number of occupents of the dwelling and outlets ie 2 adults 4 children bathroom and shower room would need a larger output combi than just a one bedroomed bungalow with two adults.

Also another thing to think about you can always leave the hotwater cylinder within the central heating system with the two way valves etc.
the cylinder connected to the bath hot water tap only and just use the combi hot water for sink,basin and shower. The shower cold would have to be connected to mains supply, but this would be the same if you went combi hot water alone. (ripping out the cylinder, domestic water cystern in the loft and also the feed and expansion cystern in the loft). quite a bit of work either way.

  Pamy 17:51 23 Jun 2008

Worcester Bosch is a good named boiler. You do not have to remove the old cylinder or water tank in the loft etc just leave them where they are, empty.(saves the cost of removel)

  Forum Editor 18:01 23 Jun 2008

You'll have constant hot water on demand, and electronic ignition - no more pilot lights. The boiler will have a self-modulating burner, so will be far more energy efficient - and cheaper to run.

Your plumbing will need to be adapted to route the water main to the boiler position, and all water in the house will be on the mains. Turn off one valve and both hot and cold water are off.

You'll have a small white plastic pipe going through the wall of the house to a nearby gully - that is for the condensate to drain. Whenever the boiler is firing you'll see a small trickle of liquid from this pipe.

In addition you'll have a safety vent pipe running to the outside - it will be in 15mm copper, and is there to vent hot water from the heating system in case of an over-pressure situation; in practice it almost never happens.

Your installer - who must be CORGI registered by the way, may tell you that he has to increase the size of the gas supply pipe from the meter to the boiler position. It depends on the capacity of the boiler you go for; the bigger models need a 28mm gas supply pipe.

  wjrt 18:26 23 Jun 2008

recommend Vaillant

  Ventad 19:41 23 Jun 2008

most plumbers would recommend that all redundant pipework etc should be removed, and if resell of the premises is on the cards at a later stage I would suggest the surveyor would inform the buyer that there are redundant water systems in the house that need removing. If you are leaving cistens in the loft they need to be completely cleaned out and dry, just turning off the water to them and draining via tap/drain off point does not drain the cysterns fully or clear the sludge at the bottom if they have not cleaned out at regular intervals.

  Ventad 19:43 23 Jun 2008

sorry that should read: especially if they have not been cleaned out at regular intervals

  gibfish26 20:06 23 Jun 2008

thanks to all for your info,there is only the two of us now retired,bungalow is detached but it has cavity insulation and double glazing,we do need the boiler for hot water and heating so i dont think we need a large one,the one we have now is only about 40,000 btus,it works fine but i have been told it's only about 60% efficient,with the ever rising costs of fuel we feel it would be more economical to upgrade to a new one.once again thanks to you all.
gibfish26.

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