malfunctioning thermostat

Vero

Hi, it was 15 degree Farenheit outside when I woke up this morning, and 49 degrees inside my house.



First, I checked the water level in the furnace, and it was fine. I've been out of heat before, and when I increased the water level, the furnace would start. Last year the plumber came and disconnected the autofeed when I was out of heat. He diagnosed the problem as being the autofeed which had functioned just fine for the 13 years i have lived in this house. He told me I was simply lucky, so he disconnected it, and the heating came back. Now I have to constantly add water to the system, and I still don't have any heat. But that wasn't the solution to the problem this morning, but it will be a problem should I ever go on a winter vacation.



Anyway, I turned the thermostat to the max, 90 degrees F, and the heat kicked in. So I figure it's the thermostat. The plumber is supposed to come to look at it tomorrow. This is a fairly new thermostat, maybe 10 yrs old. What is likely to be the problem? the unit itself? or the connection going from the unit to the furnace? The furnace doesn't seem to be the problem; it is only about four years old. Do I call the plumber or the electrician?



I appreciate your insight. I am just a homeowner who doesn't want to pay for solutions that don't work.