ok i can relate i just picked up a ranco to run my backup rack for a friend having issues with 2 many snakes not enough racks. Do you have any other temp probes at home. Second from recent personal experience do you have the temp probe sitting on your heat. Second the accurite takes ambient temp and the probe from you thermostat if placed against the heat source will read hotter due to the fact that it is picking up surface temps. Do you have a temp gun to check your temps for surface temp.