Vaillant EcoTEC Pro 28 - radiator flow temp locked to 50 degrees

[JoeeeeeeV]

Hello all,

I’m looking for some advice on my Vaillant boiler, which is controlled by my Hive thermostat. I have set the radiator flow temperature to 75 degrees on the boiler control panel, but the actual temperature never gets hotter than 50. I have done some checks, and believe I have found the problem:

• If I put the boiler in test mode, it very quickly heats up to 75 degrees. As soon as I leave test mode, it drops back down again to 50.
• On setting D.005 in the installer menu, the value is showing at 50 degrees. I think this is what’s causing the issue.
• The manual suggests that this setting can be changed by adjusting D.071, and an ‘eBUS control’ can override this setting if fitted.
• D.071 is set to 75 degrees.

I therefore believe my issue is that I have an eBUS fitted, which is locking the max flow temp at 50 degrees.

I don’t actually understand what an eBUS is, so I’d be really grateful (and a lot warmer!) if someone could let me know the following:

1. Is it possible to disable or adjust the eBUS settings from the boiler control panel?
2. If not, how would I go about fixing this problem, and is it a job that requires a professional?

Many thanks,
Joe

 

[John.g]

Can't advise re eBus.

No outside temperature compensation installed?.

Also just ensure that d.17, (flow or return target temperature) is set to 0.