Gas pipework, appliances and chimney/flues need to be maintained in a safe condition. Gas appliances should be serviced in accordance with the frequency given in the manufacturer’s instructions.
If these are not available, annual servicing is recommended unless advised otherwise by a Gas Safe registered engineer. Any gas appliances owned by tenants are not the landlord’s responsibility, however the connecting pipework and flue (if not solely connected to the tenant’s appliance) remains the responsibility of the landlord to maintain.