Arrived at location on 9/7/21 - checked over unit, had hard time getting pilot to stay lit, found thermopile only producing 330mV, replaced thermopile. Pilot is now easy to light, customer has no oil for vat, verified that the burners lit when thermostat turned on. Was unable to test thermostat but found no other issues, found the thing in burner tube is the heat spreader and is supposed to be there, confirmed unit working correctly at this time.