Ensure an annual gas safety check on each appliance and flue used in the property. Normally you require to get a Boiler Service and a LLGS (Landlords Gas Safety) certificate.
On 1st October 2015 the Smoke and Carbon Monoxide Alarm (England) Regulations 2015 came into force. Private rented sector landlords have been required to have at least one smoke alarm installed on every floor of their properties and a carbon monoxide alarm in any room where solid fuel is used.
Please visit the HSE site to find out more information: http://www.hse.gov.uk/gas/landlords/dealing.htm#responsible