Combi Hot Water Temperature

[stevecase51]

I just had a new Vaillant ecotec plus 831 combi boiler installed. Everything seems OK so far, but I have a question relating to the hot water temperature. The installer set the temperature to 55 degrees. When running the tap, the water seemed to get very hot - certainly too hot to put my hand in. I turned the set temperature down to 50, and this gave a more comfortable temperature, although I would have said it was more than 50 degrees. I played around with the setting to check that the boiler was actually responding to different settings - and it was. Now with the DHW temperature set to 50 degrees I ran the hot water tap for a minute or so, to make sure the temperature was stable, and then I filled a small thermos flask and inserted an accurate catering temperature probe. The reading was 55 degrees. My question therefore is how accurate is the DHW temperature setting of the boiler supposed to be? Is this kind of difference normal, or does it look like a dodgy temperature sensor in the boiler?

 

[oz-plumber]

Does the temperature of the water fluctuate much when the tap has been on for a minute or so, or is it a constant temperature.

If its constant and not adjusting to the temperature dial on the boiler you may well have a faulty temperature sensor.

 

[Unregistered]

Thanks for your comment. Sorry - I now think it was a false alarm. I did another experiment. This time I let the hot water run (at about half maximum flow rate) for one minute. I then filled the thermos flask and measured the temperature, leaving the water running. I then emptied the flask and repeated this process two more times. The temperature each time was just over 50 degrees. I guess when I did the original measurement I mustn't have allowed enough time for the temperature to stabilise.

 

[stevecase51]

Thanks for your comment. Sorry - I now think it was a false alarm. I did another experiment. This time I let the hot water run (at about half maximum flow rate) for one minute. I then filled the thermos flask and measured the temperature, leaving the water running. I then emptied the flask and repeated this process two more times. The temperature each time was just over 50 degrees. I guess when I did the original measurement I mustn't have allowed enough time for the temperature to stabilise.

 

[newcastle phill]

Thats great news. Pleased your all sorted