We bought a 100 year old home and did extensive addition. New addition has 2-45 gallon water heaters, gas forced furnace for new addition. Old part of house is heated by boiler. Remodeled kitchen and added cooktop with exhaust fan which is brand new and vents through attic. We moved in and almost immediately boiler coupler went out. Told we have negative air pressure in home now because we replaced windows, roof, etc. So we added a equipment room (framed and drywalled) with an open window constantly in that room. Door is always shut so if boiler needs heat when starting it pulls from outside air. That doesn't seem to be working. Small piece has been replaced that causes boiler to shut off when air is not released. This has went out twice since November. First time we thought because we left the mech room door open and ran fan on stove. This time, everything was closed And fan was not run. I'm at my wits end! Any suggestions welcome, including calling in another te h for another opinion.