I bought a house in april and it came with a 2006 Weil-McClain WTGO oil fired boiler w/tankless heater as the heating source. I tested the boiler when i bought the house and it worked fine so i left it alone till a few weeks ago I fired it up for the beginning of the heating season and heated up the house. after a little bit I noticed it turns on once every 15 min for 3 min even after passing the thermostat setting. Today when I woke up it was 80 when i had it set at 60. I am not using the tankless heater which is capped off. Could this be an issue? other factors include- my house is about 1800sq feet, its radiant heat (cast iron) that is original to the house 1884, all new windows and re-insulated in 2008. An energy audit said i needed 53k btu boiler but mine is 126,000 which i'm learning now they seem to just run grossly oversized boilers for some reason but its wasting my fuel! At this rate i will use up my tank by mid january- is there any way to derate my boiler and use a smaller jet or is there actually something wrong with the unit or thermostat. If i can't solve this issue i will probably have to choose another heat source and NG isn't available by line here .
any help is appreciated I'm new to boiler systems and i couldn't find my issue already answered here so i figured id ask, I will probably be calling someone but i like to do my homework first so i know what needs done.