Dryer heats & tumbles but not drying
I seem to end up inside my DQW150 about once every three months with dryer problems.
With the symptoms you're describing, and working from easiest to fiddliest, I'd start with checking for a blockage in the drain pump and the hose down to it from the bottom of the tub (drying seems much more sensitive to pump trouble than draining and spinning on this machine).
Then I'd run it with the back off and see if I could see condensing water trickling down the inside of the condenser (translucent duct fitted on the back of the tub). If you can't, it's usually because the solenoid on the cold water valve has burnt out again (this also usually results in the clothes getting much hotter than usual).
EVERYTHING FROM THIS POINT IN NEEDS THE MACHINE DISCONNECTED FROM THE POWER SUPPLY
Next, I'd unscrew the top of the breather tube from the top right hand corner of the case (as you look at it from the back), ease it down so the end rests in a bowl on the floor, and give the corrugated hose that attaches it to the bottom of the condenser a good squeeze to see what comes out. If this breather or its hose get blocked with a slug of wet lint, the dryer becomes amazingly inefficient. If at all suspicious, unclip the hose from the bottom of the condenser and rinse the breather (tube and hose together) through under a warm tap until all the rubbish is gone.
Finally, if none of those things bring any joy, I'd wash the lint out the condenser. This is a slightly fiddly job - the best way I've found is to take off both top and rear panels, then remove the condenser and blower from the machine together out through the top of the machine. Once they are out, they can be split and the condenser can be flushed by running warm water through it. Make sure you've got a good socket set before you begin - Candy don't believe in standardisation, so you will want every size of socket there is from 5.5mm up to 10mm before you're finished. Before putting it back together, have a look at the inside of the blower and check for any evidence of the impeller having become distorted, or of it fouling on its housing. On reassembly, be careful the rubber seal between the blower and the heater duct fits correctly on all four sides (it's easy to get one flange tucked inside the duct), and mind your knuckles as you're replacing the lower of the two blower fixing bolts and the screw which secures the condenser near the top of the tub.
Between them, those things usually cover it.
A.