Yeah, she can enter to maintain her property, in this case her boiler. Like she said, either she maintains the boilier or you move out and a more reasonable person moves in. She will have to give you a 30 day notice to vacate if that is the path you choose to take. Either ask permission or go buy your own place wher you can do what you like. Even if the Tenant refuses to grant permission, the Owner can still enter the unit. For more information you can refer this link.