Hi, Helen, it may be that although it is Diplomat they are made by different manufacturers .Yours may be different.Turn the machine on, when it bleeps,open the door and count the flashes of the start light between pauses.If it is 1 flash,pause.one flash ,pause then the NTC heat sensor is faulty.If 2 flashes,water in the base.3 flashes no heat.4 flashes no drain.7 flashes flow meter failure.If you need any more help, please ask.All the best.
FOXY
November 2008