What is the fine-grained topic of the following text: This Honeywell L7224U-1002 Universal Electronic Oil Aquastat with EnviraCOM Communication electronically monitors and controls circulator, burner, and boiler temperatures and provides electronic temperature sensing in an oil-fired hydronics heating appliance (not included), and is UL recognized. Only return the topic.
Honeywell L7224U-1002 Universal Electronic Oil Aquastat with EnviraCOM Communication