We have an older fuel oil boiler, approx 15-20 years old. Its a 1800 square foot home.

So i have a couple of questions. We are using about 5 gallons of fuel oil a day and we don't keep it warm its only like 68. While outside temp has been around 5 degrees.

We purchased the house during the summer and did have the boiler serviced before winter. We did run into some problems with the expansion tank getting water logged its one of those huge barrels hanging in the joists. No matter what i did it will just get over 30psi and start to blow off from the relief valve. So i just turned off the water to the boiler so extra water couldnt get in. The water temp on the boiler doesnt get higher than 180f and the water pressure is right around 20 psi now. Do you think that i lowered the efficency of the boiler by not letting in enough water into the system.

I have tried several times of draining the tank and refilling it. It also has one of those atrol things attached to the tank, i have heard those are awful and are hard to fine tune.

Would it be worth just buying a #60 expansion tank with the bladder inside, turn off the valve to the old tank switch it and call it a day? Do i need anything else with the new kind of expansion tanks? Are the air seperators required?