New Condensing Boiler - water is only partially hot

[Dave-Sandra]

Hi, I had a new condensing boiler installed in June to replace my 20 year old Potterton which was working fine but was very old. After it was installed it was noticable that the hot water was not heating up as well as before. It takes about 3 hours to get a very hot flow of water out of the hot water cylinder in the loft which it would only take about an 1.5 hours before! The boiler installed is a Gloworm that is suitable for my type of house and bigger so that side of it is ok but the plumber who installed it thinks that the problem may lie with the hot water cylinder and scale. before i have to pay our for a new installationof a cylinder (around �1k) can anyone suggest further checks they should do as they have not done much apart from checking the cylinder thermostat that seems to be fine and telling me that the water seems hot in and out of the hotwater tank by feeling the pipe? Could they flush out the pipe going into the cylinder etc?

[gucciman]

to comply with the energy efficiency regs and probably building regs when they installed your new boiler they should have also upgraded your cylinder to one with the latest high heat recovery coil, as well as fit thermostatic radiator valves to all but one radiator and i think the pipework from the boiler to the cylinder is also meant to be fully lagged to comply. this extra requirement and expense is why most installers and householders go for a combi replacement instead of a traditional boiler/cylinder/tanks system.
thinking logically i would doubt the problem is to do with scale if the hot waer was working fine with the old boiler a day or two before the new boiler was fitted and now it isn't .
i'm not brilliant on the old systems so cant really suggest anymore, you need to ask gasman but to get him to answer you will probably need to repost this questio in the main home and garden section.

[Dave-Sandra]

Thanks for your help - I have re-posted the question in H&G.