If you have an old school compression tank such as that, you will have air problems. With an open style tank it is imperative that you do NOT install good air elimination as you will remove the air from the loops, the air in your compression tank will dissolve into the water, flow through the system, be removed, and the next thing you know the air in the tank is gone and you have to room for expansion. Air for the air,,.., get rid of the compression tank, have a diaphragm style tank be installed along with a high quality air separator installed in the proper location in regards to your pumps and your air will be removed within an hour or so of runtime.
As for the boiler,,,, natural gas typically is the way to go and will require far less service over the years.
Were it me,, I would install a wall hung condensing boiler such as navian. . This will also give you an on demand water heater as well. Good luck
The number one thing that should be on your list of options is to find another service company. From what you've explained the one you're using now may understand oil fired equipment, but they don't understand hot water heating systems.
Long term plans (10+ years) require information first and then life cost verses function decisions.
You're already doing the first part by gathering information. I would suggest a notebook/scrapbook to collect all the info. and any thoughts you have plus a segregated bookmark on your computer browser to save links that you find. This information and education will allow you to understand what your being told and what is being suggested when you make your decision on repairs or replacement.
The investment you are going to have to make is going to be a large one no matter what route you take. The advice I give customers is to think it through and then consider options that once the money is spent (whatever you spent it on) won't end up being taken out and replaced (thrown away) down the road when anything else is done.
At the moment your hot water is the issue that drove you to doing the research. Ok, you seem to be leaning towards an indirect fired hot water heater connected to your boiler as the better option. I agree. And yes, they are a big investment. But! If you do your homework and get one that is the correct size and one that has a lifetime warranty it's a one time investment for as long as you live in the house.
The addition of the indirect to the existing system is going to require modifications to the piping/pumps/controls at the boiler. This means to have it done correctly (and not have things thrown away or replaced later) you need to find a contractor that specializes in hydronic heating systems, because it sounds like the company you're using now thinks what you have is fine and working correctly. From your pictures I would basically take everything that you have there and redesign and install it in such a way that no matter what you do in the future, it's good to go. The oil boiler would remain with a few modifications.
The cost of the indirect and the modifications can be offset somewhat because your oil boiler will no longer have to stay hot 12 months out of the year as it does now to keep the DHW coil in it ready to go at a moments notice. The modifications could also end up saving you fuel costs due to better circulation and response to thermostat calls for heat.
I'm with fire control, I'd gut the room and do it right. I just had a situation were a guy had a high Eff boiler piped about as bad as it gets, I gutted it, did primary secondary, spirovent in correct spot blah blah. End result they were so impressed at how well the house heats and the boiler didn't short cycle all day. They were glad to pay me let's say
How many gallons if oil so you use a year and what is your average cost per gallon? Also what is the installation cost to add natural gas to your home, and what is the cost per therm they will charge? We can give you a return on investment cost by switching. My thinking is that if the system needs to be repiped anyways and natural gas has a good return on investment then replacement may be a better option as that is the best time to repipe it..
the picture of numbers you posted is the mfrs tracking number.
most likely, the data plate for that unit is on the left side of the unit, gold/yellow in color.
That unit, when functioning properly, should give you an almost endless supply of DHW.
Here is how your dollar cost for usage pans out. You said you paid $3.99 per gallon if fuel oil. You did not specify what the cost per therm of gas would be so I used my cost of $1.37 (yours may be different so the numbers may be slightly inaccurate)
Comparing apples to apples your cost per therm (100,000 btus) for fuel oil is $2.85 Your cost per therm (again using my rates) it $1.37 per therm. With an assumption of a condensing wall hung boiler being an average of 90% efficient and your oil boiler being 83% efficient then...... True heat output for fuel oil would be $3.43 per therm actual heat into the home and $1.53 for natural gas. This means that fuel oil is 2.24 times more costly to operate that natural gas.
I would look into the cost for extending the gas line to your home. Replacing the boiler, upgrading the piping and installing an indirect at that time or installing a combination boiler/water heater is what I would do. Just my $.02
As his radiation is multi-zone baseboard that has to be taken into consideration when figuring savings when considering a condensing boiler.
The actual efficiency of the condensing boiler is based on return water temperatures, if the zones can not provide enough temperature drop, the return water temperature will not allow the boiler to condense (achieve it's advertised max efficiency) during a majority of the heating season.
Accurate heating load calculations and assessment of the existing radiation might prove that his situation is one that can take advantage of a high efficient condensing boiler during enough of the heating season to justify changing boilers simply for fuel savings. The trouble I've run into time and time again though is the original installation wasn't done with any math to back it up. The outside walls = X amount of footage and that's how many feet of baseboard went into the job give or take available stock lengths.
Hydronics is only done correctly after all the math is done correctly.
The upstairs zone is ~115 feet of copper and fin base board and the downstairs is ~45 feet. Is there more information needed to determine the estimated temperature drop on the loops?
Also, is there an industry accepted hydronic certification for boiler techs? It seems most people on here are much more scientific than the boiler techs I've dealt with the past few months. I'm still at a loss on how to actually find a good hydronic oil boiler tech in the VA/MD/DC area. There should be a way for pros on here to advertise their competencies and service radius. That way we could look up posts by pros as research prior and have a way to call them up directly. I know there's the map on here but there's nothing (that I've found) that associates pro's userIDs to the companies they work for. Or better yet, for pros to do side work for themselves if they want.
Ok...I'm an idiot. I believe my lack of DHW is just the "cold water sandwich" phenomenon. Today I had a particularly short hot water interval and decided to power on through the cold/luke warm water to finish my shower. To my surprise after about 3ish minutes the water started getting warmer and warmer and after another few minutes it was piping hot again. The funny thing is I remember seeing the term early on in my initial discovery of this site but didn't think anything of it at the time. Then today the light bulb went off and I realized the meaning. So, I guess now my initial reason for doing research on the boiler is out the window. But the fact still remains I burned through a 140 gallons of oil the past month and it wasn't particularly cold. Now my focus will be on minimizing cost of operation by making what I have more efficient now before deciding on a new unit, maybe this summer.