Boiler keeps needing to be reset - Water on return too hot

[Richard2Tatton]

Hi I wondered if someone could give me some advice on setting our boiler temperatures etc as it keeps shutting off when you need it most for the central heating.
The boiler works fine, the hot water tank has a temp of 78'c and the boiler shows green light flashing or solid red light ( Potterton 50 approx 5/6 years old) When you press reset the pump runs and boiler lights and runs for 10 minutes and then shuts off.
if I increase the tank temp the system runs for longer but indicates the water coming back to the boiler is dangerously hot and shuts off.
Other info,
Room stats activate the pumps & boiler around 23 to 25'c.
Boiler output thermostat is set to 3/4 approx - (no scale)
I know its a settings problem, 3way valves work etc, I've suffered it for a couple of years but thought I might ask as I'm new to DIYNot, thanks Rich

 

[WDIK]

and the details of the anonomyous boiler is to be a secret till how many have guessed?

 

[Richard2Tatton]

Hi Its a Potterton Suprima 50 for those that are waiting and guessing, as its my 1st time on this site I wasn't expecting a full Sp required on the item, it was a general enquiry, not requiring a full technical breakdown, a few general ' try this or look at that's are all that is required.
Regards Rich

 

[HarrogateGas]

Try replacing the PCB........... do a search for Potterton Suprima and youll know why I say this.

 

[D_Hailsham]

the hot water tank has a temp of 78'c

Assuming you mean the hot water cylinder, that is much too high a temperature. It does not need to be any more than 60°C. At 78°C, not only are you wasting energy heating the water but the chalk etc in the water will be deposited on the calorifier and the inside of the cylinder, reducing its efficiency.

 

[Richard2Tatton]

Thanks for this info - basically they are a cheap load of XXXX and with a load of dodgy circuit boards that doesnt fix the problem anyway,

Potterton a name you can trust!!!

thanks for your honesty and great information.

Ill get my local Corgi to replace the lot next spring as we want a decent shower fitting next year anyway.

Many thanks for your assistance everyone on the Potty Sup 50

Rich