Plumber question regarding oil fired boiler

I hope this is the right forum for this! I just had one of those hybrid hot water heaters installed, taking my hot water off of my tankless coil ($$). My HL/LL settings had been 190/170 as the coil was 20+ years old and without those settings my water was cold. At the recommendation of the reading ive done, I set the new HL/LL to 180/130....as the boiler obviously powers my hydronic heater system. I have a new aquastat which is digital so theres some other settings I did not mess with as theyre above my level.

My question is, when the boiler hits the LL, it will run but won't bring it to 180. It only goes to about 150 or so and shuts off. I am just wondering why? Is the 180 HL on when the tstat is calling for heat, leaving a 20 degree swing when it's at "idle"?

My apologies for my ignorance on this - just trying to understand and make sure I have this at the optimal setting.

 

To many unknowns

Is your Water Hot enough or does it feel cold??

What do you mean by Hybrid Hot water heater I am guessing other the a Domestic Hot water coil .

You have checked that your High and Low switch is accurate ?