blockage in drain line. Check your hose isn't kinked
Tony, November 2009
F4 water not heating up. Either the heating element or temperature sensor has failed or the control board has a fault. Not a simple job for a DIY person. Suggest you call someone out to fix it.
Lincoln Appliance NZ, November 2009
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I can answer this question...
How can I fix my F4 code (Fisher&Paykel model DD603)?