pipework size for replacment boiler.

Hi.
i would appreciate any info on the following.
I am about to replace my cenral heating boiler.
Having 'trailed' through brochures for all different makes of boilers and itemising all the pro and cons to decide which boiler (or boilers ) would suit the purpose ..the pipe work dimentions are an item I'm not sure about.
My exsisting boiler has 15mm gas supply and 22mm water feed and returns.
There are boilers which would suit my requirements but they have 22mm gas supply or 28mm water feed and returns..for these boilers is it possible to use reducer fittings when installing the new boiler.

Thanks for taking the time to assist me.

you need to be corgi registered to change your boiler , by your question i assume you are not and i suggest you get some one round who is , as it not just a case of pipe sizes !


Arf

Thank you for the reply Arf..

the work will be done by corgi registered person.

I am just putting to gether which boiler I would prefer to be fitted making a short list to discuss with the corgi guy which boiler.
to keep the short list constructive do not want to include any boiler which will not do because of the pipe size problems.

thanks again.

most decent sized boilers now need 22mm gas and must be condensing

as for the flow and return if the spec says 28 then you need 28

they don't write these things for fun you know

Thank you kevplumb for you reply.. sorry about the delay in answering.

This morning rang the technical dept of Baxi asking the question re pipework sizes (I am interested in their Baxi Platinum range or the Solo HE range. . Both these types of boilers which are really identical boilers )
both have 22mm gas supply and 28mm flow and return.
Explaining that my gas supply to present boiler was 15mm and flow and return 22mm.
The info given from Baxi tech dept. was.
on the solo 12 and 15HE if the gas pressure was 17mb or more with the 15mm feed then that would be ok.
On the water feed and return the boiler has actually got 22mm connections (28mm in the brochure) again this would be no problem on the 12 and 15He boilers (40,000 and 50,000 btu's) but any greater output boilers in this HE range they would have to be increased to 28mm flow and return.
Also (very important!) providing the installation was carried out with a 17mb +pressure and 22mm on the 12-15He boilers this would not invalidate the warranty (2 years)
I explained that all the work would be carried out by regestered Corgi person and the installation signed off.
With this information I am now certain this will be the boiler I will have fitted.
Hopefully this info will be of some use to someone else when going through the process of boiler selection.

logically minded.... you certainally seem to be

In my experience the wish list is more often:

Will the water be Hot whenever I want it?
Can I have the heating on and hot water?

and that old favourite but hard to satisfy....

Can I have a White One?

Some people want everything

Its amazing how some posters compromise quality for the sake of a few quid.

17mb may be ok according to Baxi, is it ok with Corgi and what happens when you turn other appliances on like a cooker.

What happens when the RGI say he cannot install it because the pipe is too small. do you just keep looking till you find one that will, maybe for cash in hand and a problem speaking English