Ideal 32 system efficiency level

[CMPropsvcs]

I’ve had an Ideal Vogue 32max/gen2 system boiler to a Megaflo fitted a week and running it at Flow temp 73 degrees to getting a return temp of about 55 degrees C, I’m seeing the LCD screen saying the efficiency level is only 25-28%. Has anyone else seen such a low percentage? I know for a fact the boiler has been installed correctly by an Ideal accredited installer. The weather has been cold but we only have the Hive stat set at around 20 degrees so. it exceeded i’ve.

 

[Timmy D]

Need a lower return temp to get into condensing mode. Below 54c.

Drop the flow temp by 5c.

 

[John.g]

Nobody seems to know what this is based on, if its based on the actual condensing vs the max then 25 to 28% might be considered good since there is virtually no condensing at this return tmperature.
I have seen figures somewhere that showed a efficiency of 60/65% with a boiler return temp of 40/45C which would give ~ 94% efficiency, a increase of about 6.5% over a non condensing efficiency of 87.5%ish so if condensing loss is 10% then just maybe this magic efficiency is, 6.5/10, 65%.
If you reduce the boiler flow temperature even temporarily to give a return of 40/45C, that might give some idea of where it comes from.