alpha cd28c hot water problem

[ma876]

Hi all I have problem whith the hot water not getting hot, when the hot tap is turned on the boiler fires up and the water starts off hot for a second but then the temp drops to luke warm when running, whilst checking at the boiler it is noticed that the gas heater (flame) goes out reignites for a while then back out to reignite again, it keeps doing the while and water demand is present. So far the Primary Temperature Sensor and the DHW temperature Sensor have been replaced with no improvement. the central heating side works fine firing up and staying lit untill requires temp is reached. one thing that has been noticed is that the fan is quite noisy when running slower speeds.

 

[Heating one2one LIVE]

First place to start would be the gas(inlet and burner pressures).Can't work on that unless you are Gas Safe.

 

[ma876]

my brother in law is gas safe registered and has been working on the boiler. I`m just after sugestions of what to check next, thanks for your reply.

 

[lightning]

Does it do this in central heating??

 

[ma876]

no just on the hot water

 

[lightning]

Blocked plate, gas pressures need adjusting{will need RGI for this}

 

[ma876]

thanks for the responses so far, it's greatly appreciated. Will update as soon as the items have been checked.

 

[ma876]

Thanks everyone for your help, it did turn out to be a blocked plate, added some fernox f3 and with in 5 mins all was fine again!! can`t belive how much sludge the magna clean is picking up now, the system which has always had inhibitor present was cleaned about 12months ago with screwfix no nonsense cleaner, just goes to show that you get what you pay for.