I am trying to put a furnace in my garage but only the fan runs I don't want a thermostat as I will shut off when temp is comfy, but furnace has a thermostat at the top of the furnace but can't figure how to wire it
The thermostat on top of the furnace may be there to monitor the temperature inside the boiler. Can you show us a picture?
It is not good to set up a furnace to run using only a manual shutoff. You might forget and leave the room and then the furnace runs forever.
The good conscientious technician or serviceperson will carry extra oils and lubricants in case the new pump did not come with oil or the oil was accidentally spilled, so the service call can be completed without an extra visit.
The furnace will not operate until you make the circuit through the switch/T-Stat on top. Theres a reason for the T-Stat. Safety. And thats why it will not run until you find out how to wire a furnace.