Do you have an in-line filter on the wand? Lots of guys do and don't even know it until it gets clogged. Take all the fittings off where the solution hose plugs into the wand and clean them out. If there is a small screen inside that will be your in-line filter.

By the way welcome to the best carpet cleaning forum in the world!

Both of the above post were right on track. I also had a situation where I was not getting proper pressure at the wand even though the machine was showing full pressure on the gage. It turned out that a new liquid detergent I was using had really clogged up bad at the quick connect on the front of the machine. Some detergents just are not cut out for higher temperatures and tend to clog the works up. If you have been using this detergent for a long time w/o problems then I doubt if this is the problem,but if you recently switched to a new detergent whether liquid or powder it very well could cause it and pretty quickly I might add. Only about a few days of using that new detergent clogged mine up something fierce. I went back to my Matrix All Fiber Rinse and Matrix Finish First and never a problem since. By the way, when you did the descale did you run some through your lines too? I always finish off my descaling by running it out through my hoses and wand followed by clear water rinse. One last suggestion. If you don't already have one I would recommend a water softener. I run my water through a whole house water filter into my water softener and on into my clean water tank. The filter I'm talking about is just a cheap home filter you can pick up at Lowes or a number of places for $30. to $40. The replacement filters are cheap too and they last several months. If things are getting clogged up then it is either your water is too hard or there is a problem with your detergent.