When your property is let for tenancy. It is then a responsibility for landlords to use a registered GAS SAFE company to check that all gas appliances are in safe working order and comply with current gas safety standards.
With all gas appliances, you are advised to have them serviced once a year to help prevent breakdowns, as advised by manufacturers. This will also help you get maximum heat for minimum cost.Landlord certifications for landlord protection and tenants' safety.
Yearly checks are to comply with relevant laws governing the gas industry and to ensure your gas appliance is fitted correctly, You have to retest gas appliances every year for the relevant safety checks.
Please remember prior to re-letting of a property that even if you have already had an up to date running certificate, you will need a new certificate to comply with landlord safety regulations when your new tenant moves in, this is because some times gas appliance have had broken controls ( from experience) and not been reported to landlord. so the appliance can not be used as it was designed. i.e broken control knobs on cookers and hobs.