Central Heating Question

Installing a new combi boiler do i need to replace the whole system?

My heating system is quite old and i need a new combi boiler replacement. If I keep all the old sytem and only replace the boiler and do a power flush will this be acceptable or will I have problems in the future with my new boiler. Is it advisable to replace the radiators and pipes myself ( I can do this) before I get the boiler fitted. Where do I stand with complying with building regs if I do this myself. Also will the work still be signed off by my engineer.

1 Answer

Best Answer


Generally speaking if you do a power flush and your system is ok you can just change the boiler. You don't say if your existing boiler is a combi, if it is not you will have to have a direct cold supply from the main and a hot water connection to your present hot water system from your new boiler. You will also have to adjust the pipework from your hot water cylinder coil and your header tank. Any new boiler with very few exceptions will also have to be condensing, which means you have to have pipework from the boiler to a nearby waste pipe or a dedicated soakaway. If your existing boiler is a combi you should be ok to just connect up the corresponding pipes to the new machine. It probably won't be condensing so you will still have the requirement for a condensate outlet or soakaway.

If you are able it is relatively simple to change the pipework and radiators which is where the majority of the cost lies. You can save a lot more money by using hep20 plastic pipes and fittings. No solder and easy to fit through joists and bends. Remember if the boiler is gas you have to get a gas safe engineer to fit and comission it. He does not have to fit the rads etc so just go for a simple boiler exchange and do the rest yourself if thats what you want to do. New boilers are from £550 to £1100 ish dependent on how many bells and whistles you want. Ideal and Ravenheat do simple cheaper end numbers. Vaillant and Worcester are the more pricey. I have fitted eight Ravenheat 85CSIs over the last few years. Dead simple machines with a built in timeclock and very little to go wrong. Haven't had any problems with them.


Answered 15th Mar 2012

photofinish contracts

Member since 6 Oct 2011

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