Water Tank to Combi - would I need to change central heating pipes
Anonymous user 09/03/2024 - 3.18 PM
Hi all,
We live in a relatively new build (15 years give or take) and it is time to look at replacing the boiler.
The boiler we have is a low pressure system fed by water tank in the attic and a hot water tank in the airing cupboard.
The water pressure sucks and with a baby on the way, I could really do with some extra storage.
We've had an Eon engineer out to give us a quote and he told us that due to the piping used to connect our radiators (10-12mm by eye), they would have to replace all the piping if we were to convert to a combi, which is something I would desperately want to avoid.
Could anyone give me some suggestions?
Are you a tradesperson and able to answer this question?
Heating pipes are usually ok when replacing a gravity fed system to a pressurised mains system.
The only potential problem is that by having a higher pressure on the system this may cause a leak on any susceptible joints/fittings.
Replacing your system from gravity pressure to mains pressure ( combi ) the pipes will now have more pressure in them and being 15+ years old could potentially leak on the fittings or pipes as I say it Doesn’t majority of the time BUT it could do.! Also to my knowledge 10mm pipe is called microbore pipe and they are sufficient enough to use on the heating of a combination boiler in which you intend to fit.
On converting this system setup to a combi boiler, on completion of install, any good engineer would air pressure test the circuit ensuring it can withstand 10bar. Any fragile joints or leaks would then be identified and rectified prior to filling the system with water and pressurising it to 1-1.5bar which is a standard pressure setting for boilers. Should the system ever over pressurise through fault, modern day boilers have a safety feature which will safely release this pressure at 3bar. If the property is only 15 years old the joints should be plenty good enough to accommodate a combi boiler and it is a relatively simple process - extra half day labour from a combi swap at best and this is made up by the pipe and cylinder which would be taken from site and weighed in.
there is no need to re-pipe all your radiators if you wished to convert the system to a combination boiler.
there is always a chance something may leak after pressurising the system but it doesn't happen very often.
the main considerations to take into account before converting to a combination boiler is the water flow rate, the gas supply to the boiler which may need to be upgraded and the routes for the cold main and domestic hot water to the boiler position.
you should get a few quotes from other installers.
