Intermittent suprima 60 lockout problem

[mickfriend]

Hi- I have a suprima 60 fitted with the latest PCB kit about 3 years ago. Recently, and more so at the end of the day, the boiler has started to go into lockout.(Red light on constant) As soon as I press reset it is ok again. This intermittent fault is now happening at least every other day. As my Mum has the same boiler I have swapped PCB with hers to see if that is the problem. Mine works fine on her boiler but I still get lockout on my boiler with hers fitted which suggest it is not the PCB. I have also renewed the electrode and set the gap correctly as well as renewing the Thermistor and the Overheat stat to no avail. I can't think what else could cause this other than a problem in the wiring harness.

Any ideas?

Mick

 

[Dan Robinson]

Two things that spring to mind, but they both require an RGI with a multimeter.

 

[mickfriend]

I can access a multimeter - What two things are you thinking?

 

[Agile]

The two things I am thinking is that you need an RGI and probably did not replace the thermister correctly.

I would also be asking you to measure the flow and return temperatures around the time it usually locks out. You do that outside the combustion chamber which should only be opened by an RGI !

Tony

 

[mickfriend]

Hi Tony

I completed an apprenticeship as an industrial heating engineer (big boilers)30 years ago and then changed career so I am generally competent around boilers and gas valves although I am not up to date on current heating technologies. I did fit this boiler myself 10 years ago

Can you advise how I can have replaced the thermister incorrectly as it appears to be a simple fit for the probe to locate into the hole and the plastic body to clip into the fitting

Can you also please advise how I can measure the flow and return temperature when the boiler is in lockout. Do I need to obtain gauges? Are you thinking that the pump or 3 port valve could be causing the problem?

Mick

 

[mickfriend]

Sorry - One more thing . When the boiler goes into lockout the Red light is flashing rather than staying on as I stated in my earlier message

Mick

 

[Baxmax]

is the red light flashing rapidly ?