Thermocouple completed heating maintenance on one Hot water boiler removed and clean burners and replace thermocouple and clean pilot assembly. Checked expansion tank and safeties also tested lower cut off and check natural gas lines and checked for carbon monoxide not detected left system working also performed heating maintenance on two Unico Hydro air handlers checked coiled and sprayed replace filter 18 x 25 by one for the basement system and replaced April air 213/210 for system located in attic tested systems operation left system systems working