Boiler venting question

Plan to renew the baxi back boiler with a new condensing boiler mounted on an outside wall. My problem is that the boiler will be mounted on the opposite side of the house to where the header tanks and h/w cylinder are located. Are there any problems with providing a boiler vent some 30 foot away from the boiler and can I run 22mm pipes from the boiler to the cylinder or would they need to be 28mm?? My boiler choice's are either Potterton Suprima or Ideal Standard Icos.

Out of that choice Suprima as I believe they have sorted the pcb now, but Neither are my choice.

Pipework will involve quite major changes if the old system was gravity hot water, perhaps the airing cupbaord is a better alternative boiler location?

Have you considered system boiler? this would be labour saving, renew all rad valves and put trv's on, upgrade cylinder to bs1566 full control of heating/hot water.

You are entertaining major work.

Paul
Thanks for your response. Yes I know all about Suprima PCB's having repaired mine twice in the old house and eventually getting an exchange board. They have revamped the electronics on the new Suprima's, but as for new boiler choice we are still open. I now live in a bungalow, and the present system was installed by a blind one-armed person of about 10 years of age who purported to work for BG!! The whole plumbing is a total cock-up and as you say will have to have extensive re-working.
Any thought about the boiler vent pipe..the flow pipe from the boiler would have to run about 40 foot horizontal, so can I tee off of the run to make a satisfactory vent to the header tank? It has been suggested that I use an air seperator with an autovent attached. Reason I was told this would be o.k is that modern boilers with micro-processors would shut down before an overheat or blow off would occur..any thought's?

you would be better off making it a sealed system for loads of reasons including doing away with header tank and open vent pipe.

rob884 said:

you would be better off making it a sealed system for loads of reasons including doing away with header tank and open vent pipe.

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Yep! I agree. Especially if your plumbing is as bad as you say and for the amount of work its going to take, I'd recommend you ditch your present system and go to Combi. It'll free-up space in the loft and in the cupboard where the cylinder is presently situated. Obviously I don't know the layout of your property but on the face of it I suspect Combi is your best option.