Potterton Suprima 30 fault

[DTB900]

Can anyone help.... I have a Potterton Suprima 30 boiler, the boiler fires up normally however the central heating And hot water fail to reach the desired temperature (room stat selected high, hot water tank stat selected to 50 degrees and boiler temp selected to high).The boiler continues to run for approx 20 mins then cuts out. The 3 port valve and overheat stat have been replaced as recommended by a local plumber but the fault still remains. The pcb was replaced with the updated siemens board 6 months ago for a different fault. Do the new boards also suffer as the old boards did???? The system has been bled and the pump is running....

 

[seco services]

can't see why the 3 port was changed.
obviously i take it the boilers still getting a signal from the 3 port that theirs a call for heat ?

 

[Boilerman2]

Why hasn't the Thermistor been replaced? thats where I'd start looking

 

[DTB900]

Thanks for the info guys, I replaced the thermistor and fault remained. Changed the pcb this morning which cured the fault. The updated boards seem to be as unreliable as the previous ones.....

 

[nickso]

Thanks for the info guys, I replaced the thermistor and fault remained. Changed the pcb this morning which cured the fault. The updated boards seem to be as unreliable as the previous ones.....

not so, thats a rare fault, ive fitted hundreds of the new boards and have only had to replace about 5.

 

[MANDATE]

relative had the lockout problem about 2005.
Changed the pcb for the second version and all was well until late 2009 when intermittent lockouts start again.
Just fitted the latest version pcb complete with frame and wiring loom so problem cured.
Examined the underside of the removed pcb and found 1 very bad soldered joint (cracked and signs of arcing) plus another 3 dodgy joints

 

[thefloosyonthebeach]

deleted