I contacted the heating and AC maintenance corporation when there was no hot water in the house.
I do not know the first thing about fixing these things. I tried to call the plumbing service, however they did not have any corporations available. I knew that the heating and AC maintenance handled some hot water oil heater problems too so I gave them a call. They had a serviceman ready to go and at my place in less than an hour. The young serviceman looked just like our oldest son! He had red hair and freckles and a funny smile. The kid looked like he was 18 or 19 years old. He was wearing a wedding ring. I made some small talk with that kid while he diagnosed the hot water heater. I tried not to get in his way, but I was trying to be friendly, and when the guy went out to his truck for parts, I excused myself to go into the house and I did not come back out until the guy was almost finished with the hot water oil furnace repair. The maintenance serviceman pointed out a bizarre sound coming from the furnace and he told me that I should have that looked at. He could not do the evaluation and maintenance until the next day, however he was certain that he could fix the issue in about 30 minutes if it was the problem that he thought. The business did not know that the furnace maintenance was going to be as involved or fancy as the maintenance to the hot water heater.