Old gas boiler using a lot of gas. How to adjust temps?

I bought a multifamily house with a Burnam Oil Boiler and a Repco Gas boiler for the 2 floors, and the Repco seems pretty old. The sticker says 1981, and there is a burn mark on the side of the boiler. The tenant noted there was a pretty high gas bill last month, so I started watching it. I see the temperature gauge swing from 140 deg F to 180F then the Taco pump turns on.. but the burner fires quite often. I looked at the oil burner and it had temp adjustments set at 160 to 180 F, or 20 deg delta T, would it help if I tighten that up on the gas burner? Problem is the Honeywell control doesn't have any recognizable adjustment to me.. I attached a few photos. Should I be doing something else to get the system working more efficiently? (i already insulated all the pipes in the basement to try to keep more heat in)



Secondly, there are rebates in the state of Rhode Island for efficient gas boilers. Should I be looking into getting a new boiler this year? the 95% ones are 1500 rebate, 90% ones $1000 rebate. I like the plastic exhaust and longer pipe length allowable of 95% boilers, but is it worth changing? I know these old 80% eff boilers will last 30 years as this one has, and I don't want to mess with them often.. what is best low-maintenence solution?



Lastly, there are rebate for instant domestic hot water also. Should I get a combi boiler or separate units if I can get $800 rebate on a tankless gas heater as well? Again, I will pay more now if I can rest assured later I don't have to mess with it. (Currently I have separate gas 50gal tank water heater)



Thanks for hearing me out. This is new stuff to me now being a homeowner in New England..



Regards