Most modern wet boiler systems are now Combi or Condensing boilers which means that when they go wrong they will, if you are not on any insurance plan cost a small fortune to put right.Warm air unfortunately isnt that popular and many service engineers just dont like working on the appliances,but at least you have the best with Johnson& starley.The main problem with the changeover is that you will have to have water pipes to the radiators showing as no doubt your floors are solid and they dont like burying pipes nowadays for obvious reasons.The only thing likely to give you any problems on the warm air will be either the fan or the thermocouple,so if you are happy as you are i personally would make do until such a time that a major unobtainable part packs in.That could be ages.A new boiler may well be more economical to run,but you are likely to have more trouble with a newer boiler.Just look at these forums for a start.Nearly every fault reported is a Combi,yet there are still thousands of older appliances out there running ok.
Tony S, January 2009
