How to TEST my thermostat

Oil Furnace withe AC added
Using Honeywell R8184 N 1002
I know there should be voltage at the wires that connect to the thermostat.
I simply do not know how to connect a voltage tester to discover if there is proper voltage at the thermostat connection.

For reasons I do not understand, the power to the furnace is on a switched ac circuit. When I flip that switch, the circulating fan runs and blows air throughout the system.

I can MANUALLY trip the relay inside the Honeywell R8184 N 1002 and the burner will, then, start and heat the house.

So, my first step is to see if there is power to the thermostat A) when this switch is in the ON position and, then B) if there is power to the thermostat when this switch is in the OFF position.

Also, would LOVE to learn if anyone has ever had a system with a similar switch setup - that turns the blower fan on and off independently of the thermostat.

 

Its best to measure the stat voltage a the Honeywell. With the stat calling for heat put your meter on C and W. Should have 24 V.

 

What is wrong that you are trying to fix?

Most systems with a/c have a switch at the thermostat for fan Auto/On. Some older systems had a switch at the furnace for this constant fan function.