Vaillant turbo max plus - S17, S27 - ? pump problem

[mi]

I have recently been having problems with my Turbomax Plux, which is about 4 years old. Firstly I had an S33 code - which I understand was a problem with the air / flu system - I have now changed the Air pressure switch (which was relatively easy to do), and this code is no longer a problem.

However, I now get a S17 and S27 code, and the boiler works for a while and then cuts off with this code. I understand that these codes stands for " pump over run" - I wonder if anyone could tell me what this means.

Does this mean that the pump needs to be replaced or can something be done to re-set it or something - I'd like to know before I call an engineer in order to make sure I am receiving the correct info.

Thanks

Mo

 

[ChrisR]

Those aren't fault codes; just for servicing, they indicate what the boiler's doing.
Need more info on the problem...