A small blower (as you probably know) runs during the dry period to pull room air through the DD and exhaust the residual heat/moisture. The vent is at front/center beneath the DD. Depending on where/how your storage drawer is positioned in relation to your DD's exhaust, you're probably having some warm/humid air seep into the drawer. Leaving the storage drawer ajar as you've been doing allows it to dissipate better. Doubtful there's anything wrong with your DD. Probably the only workaround is to cancel the DD cycle when the drying phase starts and pull it fully open for flash-drying instead of the normal airflow drying. Note that if you do that, the DD's pump will likely run in drain mode for a minute or so when the DD is next closed.

As for the F3 error on your lower drawer, troubleshooting that involves checking if the heating element and temperature sensor are working properly. The temp sensor (thermistor) is an integral part of the ceramic heating element. Overheat protection for the element is a thermal fuse in the element circuit track which melts at 514°F to 576°F, interrupting power to the element. Apparently it hasn't yet overheated to blow the fuse, as a non-heating element generates an F4 error. 1. Is the incoming water temp higher than 185°F? If yes, adjust the household water heater. 2. Is the heating element on continuously (overheating)? If so, replace the controller board. (Note this can also be caused by a bad temp sensor, so check that also.) 3. Are the wiring connections between the controller board and element plate OK? If not, repair or replace the connections/wiring harness. 4. Moisture leaking around the element plate / temp sensor? If so, locate and fix the leak/seals. 5. Is the temp sensor OK? (check the resistance reading with a volt/ohm meter) If not, replace the element plate. For reference it should read: 962 ohms @ 68°F, 1000 ohms @ 86°F, 1202 ohms @ 140°F. So at normal room temperature (the DD is cool) the reading should be between 962 and 1000 ohms.

Cycle sequences and temps depend on the model machine involved and the target sales market (US/Canada, NZ/Aus, European, Orient), and the details may vary a little throughout the production of a given series (control board revisions). The best reference is via the specific user guide packed with a given machine. F&P has some user guides online but not for all older models. I have a few "historical" user guides and service docs. Citing my US-market DD603 bought 8 years ago: Heavy 132 mins -- prewash, rinse, rinse, main wash 150F, rinse, rinse, final rinse 163F Heavy Eco 112 mins -- prewash, rinse, main wash 140F, rinse, rinse, final rinse 150F Normal 115 mins -- prewash, rinse, main wash 140F, rinse, final rinse 150F Normal Eco 88 mins -- prewash (or prerinse if no detergent), main wash 125F, rinse, final rinse 125F Delicate 86 mins -- prewash (or prerinse), main wash 120F, rinse, final rinse 130F Delicate Eco 72 mins -- prewash (or prerinse), main wash 115F, rinse, final rinse 125F Fast 56 mins -- prewash (or prerinse) main wash 115F, rinse, final rinse 115F Fast Eco 38 mins -- main wash 105F, rinse, final rinse 105F The newest models and some market areas may reduce cycle phases (such as eliminating the prewash/prerinse and starting directly with the main wash) and increase time to compensate.

No. I installed mine ... uninstalled, moved it to a different house, installed again. Never any trouble with that. Main things are follow the instructions for moisture-proofing the cabinetry cavity, route the drain hoses properly, level it, and anchor the unit correctly with the side and top tabs.