Vaillant ecotec pro 28 HOT water too hot.

[sammathias]

Routine service today on an ecotec pro 28. Everything went fine but i noticed the customer had his hot water set at 40 degrees on the boiler...but when running the hot tap it was coming out at 69 degrees..even in p.01.
i looked at the diagnostic codes and D.003 was set at -99 degrees and D.006 was 50 degrees if i remember correctly. The boilers under warranty so i just told customer to call vaillant out.

But id still like to know what the problem actually was for future referance?

 

[MatthewHurt]

P.01 is maximum rate, so it will heat up above whatever you have the temp set too on the display.
The Pro also doesn't have a HW outlet temp sensor, so the desired set temp (D6) and actual outlet temp (D3 on an EcoTec Plus) might not marry up perfectly.

 

[sammathias]

Even if it wasnt in p.o1 and i set temp to 40 degrees it would still dish out 70 degrees...surely not right? Cheers for reply...

 

[Ollieg]

It uses the primary return NTC to get a rough idea of what the temp is. So if the NTC is faulty/not pushed tightly against the pipe you may get similar issue.

 

[Starky]

I think, on a eco tec when put into p.01 it will go to max rate regardless of what it's been set to via the display. I would of thought the manual would state this.

 

[Ollieg]

I didn't see the p.01 comments above. In p.01 it will work max rate.
Gas rate it. Check s codes when working normally.