I have a old water boiler. I'm having an issue where the boiler periodically want turn on and the house temperature will continue to drop. If I turn the thermostat up, the boiler will kick on and will maintain the set temp for some time but will eventually fail to kick on again. Based on the fact that I can get it to kick on by adjusting the thermostat, I'm assuming the issue is thermostat related but I'm not sure if the thermostat itself of the sensor...or maybe I''m totally off base.