Bissell 7920-E; No spray.

\015 I have a Bissell 7920-E that I have not used for a few years. It switches on OK. The red light on the front is on. The brushes rotate. I have filled the bladder and cleaner concentrate bottles. It will not spray. The spray indicator does not rotate..I have carried out all the troubleshooting instructions in the manual. Still no luck. Any ideas please?\015 – Bissell 7920 ProHeat Pro-Tech Upright Wet/Dry Vacuum