RD1 350 British Gas boiler circuit board

[system]

I have had an RD1 350 British Gas boiler for 14 years with very few problems.

Recently the boiler failed to respond at all, with LED 3 and 4 flashing alternatively, however on checking that all the connections were secure. the fault cleared and the boiler operated correctly. The following day the fault returned, so I removed the circuit board and checked visually for any breaks in the board tracks or dry joints, all looked fine with no signs of destress or poor soldering, I did find a small push button switch near to LED 4 and operated this repeatedly a few times. I refitted the circuit board and the fault had again cleared.

The boiler has now operated correctly for the last 4 weeks, and I can only assume the push switch on the board was not making proper contact internally, 14 years of heating and cooling probably taking its tole LOL

Does anyone know the purpose of this switch, as I say it is fitted directly to the circuit board and is not referred to in the boiler manual.

 

[45yearsagasman]

It may well have something to do with the proposed remote diagnostic facility originally planned for that series. RD= Remote diagnostics.

 

[system]

yes I think you may be correct, but I just wondered if anyone else had come across this problem or if they had any further information. The boiler has been serviced annually since installation in 2004.

 

[ollski]

It will be faulty sensors, occasionally the fan but almost always the sensors.

 

[system]

That was my first thought Ollski, but I decided to just check the circuit board connections first, and the boiler has been fine ever since. The fact that the fault then came and went and after operating the push switch a few times the fault disappeared.

The only other problems occurred in its first five years, a new thermistor harness and a very noisy fan (new bearings in the fan cured that)
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