All fitted appliances will have a 'Manufacturer's Warranty' and this is important documentation that your developer must make available to you.
Make sure that you register with every appliance manufacturer using their warranty details. In the event that an appliance malfunctions, contact the manufacturer directly and ask that they either repair or replace the appliance under the terms of their own warranty. Your new homes warranty will not cover fitted electrical appliances. All appliances receive at least 12 months warranty - some even 2 years.