F11 error code on Hotpoint Ultima CDT80 - how to fix?

I have a Hotpoint Ultima CDT80 which had an F10 error code a few months ago which i fixed by resetting thermostat. It is now showing F11, which when reading the on line help from Hotpoint this says 'F11 - No pump connection' - what does this mean and how can i fix it?

Many thanks.