Re: Diplomat ADP 8242
This shouldn’t be too serious CWH, certainly not terminal anyway.
It’s just not draining which could just be a simple blockage or possibly a drain pump failure.
Check the waste hose where it joins the sink trap (if it does) or wherever it connects to for blockages 1st.
If all seems well, you’ll most likely need an engineer to rectify for you.
If you let us know your postcode should you need an engineer, there’s plenty here who can help.
Dave.