I just bought my house last year. The previous owner had just replaced the boiler before I closed. I had oil delivered the day that I moved in. I had problems with the hot water right away as it would only get hot when I turned the heat all the way up. I had a plumber come, and he said during the installation they crossed two wires. He was only downstairs few minutes and it was fixed and that didn't make sense to me, but I didn't ask questions because it was working.
Now it's a year later and it's happening again. I checked to make sure the water level was okay, which it was. I've bled the water and filled it again to make sure there was no air. That made it normal and hot again, but it only lasted for two days. It seems to be something very small that I am missing here because if it was wires they would not have crossed again. Now, I don't know if it was just coincidence that this happened on the same day that I had oil added again when it was very low. Should I bleed the oil line? Is there an adjustment valve or something that I am missing here? Please if any could help me it would be greatly appreciated.