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Re: Old oil fired boiler for hot water baseboard
A room-by-room Manual "J" Heat load / loss calculation will tell you how many BTU/h are needed to heat the home. It was not uncommon for boilers to be oversized 70 years ago.
At 70 years you can plan on replacing that unit in the near future.
Any tags showing wo delivered the oil to the residence? Where is this home located, we might know someone in the area that is better qualified to inspect it then that home inspector.

Re: Old oil fired boiler for hot water baseboard
Could be a low speed burner. A little blurry, but it might be a 3450 ABC Sunray burner.
In either case, you'll notice the scorch marks above the burner. That must be addressed. Chamber and front plate gasket.
If you pop off the panel on the right side of the boiler, and see gobs of cement and soot, then that's what a 1970's oil fired boiler looks like. That's not acceptable in 2024.
Where are you located? A new modern oil fired boiler, together with the correct controls will be much cleaner and more efficient than what's there now.

Re: Kewanee Cottage Boiler Age Estimate
Speaking as a homeowner I am sure your home had a hand fed coal boiler with larger boiler tapping's and a great deal of thermal mass before this gas fired boiler was installed.
Are your radiators used as individual expansion tanks leaving an air charge in each radiator rather than using an open to air expansion tank in the top floor or the attic???
The large diameter piping above the boiler allows the hot water flow slowly and evenly to all the radiators in your home. There are a more than a handful of cast iron boilers with large pipe tapping's offered for home heating that could replace it.
I guess you are at the point where you could replace the boiler with the right one with the same size tapping's, new low water cut off switch and water feed valve and a single new clamp on aquastat to control the water temperature maintaining the heating systems simplicity and add that to the homes purchase cost. The installation of a new low water cut off switch in one of side tapping's of the new boiler will protect the new boiler and maintain plumbing code compliance.

Re: Kewanee Cottage Boiler Age Estimate
Trying to prove that a 70+ year old boiler won’t have any issues is an impossibility.
It’s true the block is built like a tank, but proper maintenance, water conditions and other factors also contribute to its life. There’s also the issue of efficiency. That thing was probably 60% efficient the day it was installed, maybe less. A new mod/con boiler is 95% efficient and people are very energy conscious now days.
At 70+ years old, I would insist on the cost of replacement being deducted from the price of the home if I were the buyer.

Re: Lochinvar / Knight Boiler 80-285 Issues
"The hot water heater appears to still be producing hot water which gets its heat from the boiler installed right next to the water tank. But, the baseboard heating is not giving off any heat…hence the cold house."
Nothing unusual about this. There are two separate sys. House heating and hot water heating. Hot water heating works and house heating is intermittent as you stated with your friend's comments. There can be many problems that can cause this.
Sorry to say, this is beyond your capability to fix, regardless of the help you get here. You need a professional to come in and make a diagnosis. Have him check the combustion chamber, too, it may need cleaning.
I would get rid of that old thermostat and replace it with a newer one, but not an internet type. You can take the cover off of the old one and jump the two thermostat wire coming from the boiler and see if that causes the heat from the boiler to increase the heat in the rooms.
Re: Looking for any info for the radiator in the pictures.
And it gets lots of attention. Thanks, Larry!
Re: NTI FTVN , HTP ELU-199WBN , or Navien NHB-110
It's all about installer, and somewhat about parts availability. I don't personally prefer any of the brands mentioned, but they are all decent boilers that many installers trust, and can get parts for.
T80 looks like it was an 80,000 BTU input boiler. Personally I would look at an 85,000 input if it were me, however you already have 3 quotes. 2 for 110 input, likely the smallest size those brands offer, and they modulate so its close. and 1 for a 199 input model more than 2 times the input of your old equipment. I would personally ask that installer why they quoted a boiler more than twice the size of the old one, and if they could quote something a bit closer to what is there now. of the 3 HTP is probably the one I like the most but I wouldn't want an installer to double the equipment input size on me. HTP offers a few options for 85,000 input boilers