Ariston Microgenus A77 fault (again)

[Tobaz]

I have read all the previous comments on Ariston A77 faults but mine is different. About 4 months ago the boiler failed A77. Reset cleared it. After about 2 weeks it failed again but Reset didn't clear it. Engineer eventually replaced the sensor and board. All okay for a week or two. Boiler now fails A77 about every 2 weeks or less and a Reset fixes it immediately or after a few hours. Today, came home after a few days away, switched on boiler, worked okay for its first cycle then failed A77. Reset cleared it immediately. As this weekend has been very wet and cold is this the cause? Does some damp build up in the boiler via the vent?

The boiler is 3 years old on Ariston's extended warrenty. The company the insurance company use don't seem to know the boiler in fact the information the first engineer told me was totally wrong. The company is not on Ariston's list of approved repairers for my area. I have no confidence that if I call them out again they will fix the problem.

 

[Kristoflampie]

Assuming this is a condensing boiler, check the sensor in the secondary heat exchanger isnt getting shorted by sludge or water not draining away ie condense trap is clear etc. Had a few where its like stagnant water or slime which sits on a ledge just under the fan discharge and upsets the sensor.
Best get an RGI as it means removing the fan etc to check but it does throw up the A77 fault. Good luck

 

[Tobaz]

Touch wood the boiler has worked okay since my last post. But today we noticed that for a split second after switching off the hot water and the boiler restarting for the heating an error E34 appeared. It cleared immediately. Reading the messages about E34 there seems to be a similarity with A77 in that removing the flue restricter seems to be a favorite fix. Should I get an engineer to do this? Of course, it might have failed E34 lots of times and we have just not noticed it.