Ideal logic plus 30 ABV & Super Efficiency (not)

[Alfaman]

Three questions for you experts. I have had an Ideal logic 30+ combi installed, unusually retaining the tank so it's direct feed to the downstairs taps and in a S plan configuration to the pre existing hot cylinder. To complicate things further I have a second zone which is underfloor heating, so there are 3 two-port valves. The installer said I didn't need an automatic bypass valve as there is an internal one. I have fitted one anyway as the UFH mixing valve could close and leave it pumping against three closed circuits. I used an ABV from Screwfix. Max setting is 0.5 bar which it is set to but it is continually bypassing: is this normal?

There is no pump characteristic for the Grundfos pump in the manual so I cannot follow the methods given by Honeywell or Myson for setting their AB valves (even though mine is not theirs)! Does anyone know where I can get the pump curves?

Secondly the "Super Efficiency" reading on the LCD display is 9-14%. The installer tells me he is to return to make some final adjustments but I can't see what there is that he can do to affect this, any thoughts?

 

[Scott_D]

I think super efficiency is when it modulates to minimum output.

Balancing the radiators may help a little

 

[Alfaman]

Thanks Scott but the super efficiency level is a percentage rating on a bar graph - so should be 80 plus. Bypassing is happening on hot water only so the radiators are not even in the circuit - but good general advice I agree. When balancing radiators the manual advises adjusting the lock shield with the TRV fullly open to get 20°C drop across the radiators - how do you guys measure this drop? or do you do it some other way? (by the way the super efficiency level was like this before I installed the ABV and has not changed significantly.)

 

[Scott_D]

Thermometer clamps on each side of the radiator.

As far as I know you can't tell the boiler when to run in super efficiency. It works it out itself.