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Following on from my thread about downlighters, I'm now after advice on choosing a boiler!
I live in a three bedroom semi (50's, which may get an extra bedroom in time). As part of the current building work to provide a larger kitchen, I'm going to renew the 10+ year old boiler for a more effficient model.
I currently have a 'traditional' system with a hot water tank. I am looking to move over to a combi, as I figured they are more efficient due to only heating the water you need, when you need. Is this a good idea or are there issues I need to be aware of?
I would be willing to just upgrade the boiler as it would be a cheaper option (and possibly less problematic?). Another option is to go for a sealed system at the same time. What are peoples thoughts on these?
If I do go for a combi, I am keen on the Valliant Eco Tech range (ideally with a stainless steel HE). Any other goof makes out there?
I change from a tradition system to a condensing combi in my 3 bed flat , my gas use dropped by 3000kw a year But I'll feel like I made a mistake as I'd like to fit solar HW and it can be done but it would make much more sense if I'd stuck with the traditional ,
I believe it usually means doubling up, ie trad.DHW for the solar and combi, with a diverter valve for solar HW you need a HW storage tank so you may as well have a trad. condensing boiler.
I heard of using the solar as a preheat a small panel heats a small tank then run the cold main through the primary circuit coil to the combi , not need for a main pressure cylinder. , but most combi dont recognise preheated water, so you'd need to check and I've no idea how effiecent it would be.
If you convert from an open vented DHW sytem with vented primary circuit to a sealed system is there a danger that the increased pressure will cause the radiators to start leaking all over the place? Why does the sealed system have to be so pressurised? If you had a larger capacity 'pressure vessel' with air in it then could you not just use that to absorb the additional pressure created by the expansion of the heated water?
yes you can get a few leaks, but these are easliy fixed
One advantage of a pressurised system is you can get rid of the expansion tank and associated pipework In my case and for several customers for loft conversions, though a coffin tank will fit in the eaves the same applys for a mains pressure cylinder also shower pressure and water pressure for any bathroom in the loft, otherwise you have to pump it I also believe full pumped pressurise systems are slightly more effiecent though they have the disadvantages previously mentioned
rusty chain if its not to late have you looked at the worcester greenstar CDi 27Kw combi with digitstate optimiser ( programable room stat with extras) fitted one the other day and its working well , easy fit , fully modulating gas valve, condensing in heating and hot water mode (maybe?) 3 bedsemi flow and return 40-90 oC
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