Thermaclassic f24e Combi Boiler keeps cutting out on hot water only.

[Allanp34]

Hi
central heating is fine but when the boiler is cold the hot water isn't working well. Boiler cuting out every few seconds. After about 5 minutes of this all is well and works normally.
Any ideas which part might be at fault here?

Saunier Duval - thermaclassicr f24e Combi.

Many thanks A

 

[CBW]

Likely the diverter or flow sensor - need an engineer on site really.

 

[Bod ...]

Could it not be a blocked heat exchanger?

 

[Allanp34]

Thanks for the replies. Understand an engineer brings the experience to know the likely culprit and maybe diag tools or hook up to the board to see what is going on.

Would like to avoid the expense for now. But let's see how the trouble shooting develops.

Boiler is 18yrs old so could be anything suggested so far. The only clue maybe that it' is only problematic for the first few minutes when coming in on the evening for the hot water only. Then all is good.

Think we have the same issue in the morning but I'm not awake yet!

Thanks again.
A

 

[Bod ...]

Boiler is 18yrs old

Don't waste your money. Get a new boiler

 

[Allanp34]

Unfortunately not really able to swap it out at the moment.

Can see saunier duvals are problematic. And from the bits I've replaced over the years I'd say that's a well earnt reputation...
...timer, diverter valve, non return valve, refill valve.

If we crack this problem then it might help others as well.

Thanks for the replies.

 

[Allanp34]

it is fixed - replacing the main control board with another, "as new" board for a reasonable price.

The original version was hard to come buy but replaced with a newer universal S104700 "SYMSI 7.0" which I could find over here at a reasonable price approx £100

Super chuffed, and thanks for everyone who contributed.

And yes, totally agree in the long term this thing needs changing. Fortunately I am not paying for someone to do the work - that would probably make any repairs un-economical. Recent service was done by a pro, who says it is running very well, lets hope things work ok for the winter and beyond.

It's my first time on the forum and appreciate it. Learnt some essential things from older threads.

Cheers A

 

[ianmcd]

Dont be turning the power on and off or your SYMSI board will just not wake up, they are a nightmare

 

[Allanp34]

Dont be turning the power on and off or your SYMSI board will just not wake up, they are a nightmare

thanks for the warning !!!