by law how long does my landlord have to fix none working boiler ,no separate

[David]

immersion heater for hot water? i rent from a private landlord , rent is up to date and property is kept in good order myself , the boiler if it will light , blows the pilot out every time the boiler clicks off at temp , this means if i put the heating on to heat hot water i very rarely get a hot tank as boiler has gone out , then it wont relight for hours