Yes these can be converted to any type of system in the parameter settings , flue sections are push fit only , you are not connecting a cold water supply to the boiler so I would probably add a isolation valve to the hot outlet which can be opened to check for any problems which may occur as a...
Yes compression fittings , the easiest would be a compression coupling with a imperial olive in one end and a short length of new 22mm copper pipe , but you can get 22x 3/4 solder adapters if you have the tools and skills. Kop
Completely your choice a.service type full bore valve looks neater and is only a problem is there'd is reduced access to it , saying that I often use vales with butterfly types handles. Kop
You need as drainage company to clear the blockage free the drain up and jet it , if you own the property then I'd say contact your swearage company you pay your bill to , if your in a rented property then its down to.your landord to arrange for the work to be done . Kop
Piece of mind is a wonderful thing I'd recommend replacing it all 5-6 suspect movements your chucking good money at bad otherwise, your home insurance will cover most of it anyway?? . Kop
Hhmm was there a smell when vented did water come out? test the water there's many Kits available and we should really be doing it . I would say it needs a clean and possibly a new vessel you may possibly get away with not doing it ? , but if you're gonna be there a day why not do it and avoid...
Have you physically checked the pressure in the system ? it could just be a faulty gauge or partial blockage in the tube , I'd suggest and good hot flush then a chemical clean and mains water flush check then expansion vessel is charged to 0.7 -1 bar add a couple of litres of quality inhibitor...