Vaillant Turbomax 828 heating shutting down - s7 pump overrun

[JohnK1976]

Hi all

My Vaillant Turbomax fires up when I turn the heating on, the radiators get warm and after 2 minutes it shuts down with an s7 status code of 'pump overrun'. The radiators never get very warm.

Once the boiler has cooled down the heating doesn't fire up again unless I manually turn the temperature dial down then back up (or if I press 'override' on the digistat).

I recently took some radiators off for decorating purposes but these have all been bled so there's no trapped air in the rads. Could there be trapped air in the pump?

Many thanks for your time

 

[Agile]

From what you say, which may not really properly describe the problem, your room stat is turning off after 2 minutes.

If this were the case either its faulty or is fitted above a radiator.

But what are you "turning" which implies angular movement!

Tony

 

[JohnK1976]

Hi Tony

Thanks for your response.

Even if I eliminate the room stat (by taking the batteries out) and use the heating dial on the boiler so the heating is on constant - the problem still persists.

 

[Agile]

That would indicate the boiler has reached its set flow temperature and achieved its minimum power output and has to turn off.

That may be caused by a restricted flow rate.

When was it last serviced?

What is the DHW performance?

Tony

 

[JohnK1976]

Hi Tony

I've only lived here 9 months so not sure when last serviced.

How would I measure DHW performance? The hot water is absolutely fine - no issues with this at all.

Would you recommend a service to see if any components are blocked?

 

[Agile]

If DHW fine then there is some problem there but probably with the CH controls and settings.

Not seeing your system I cannot guess at what is wrong.

I always recommend new purchasers have the boiler/gas system checked/serviced as soon as the property is occupied.

Tony