Some orchids mainly or totally rely on self-pollination, especially in colder regions where pollinators are particularly rare. The caudicles may dry up if the flower has not been visited by any pollinator, and the pollinia then fall directly on the stigma. Otherwise, the anther may rotate and then enter the stigma cavity of the flower (as in Holcoglossum amesianum).
I wish I could tell you exactly how often to water your phalaenopsis orchids and how much water to give them and be done with this post. Unfortunately, there is no one size fits all answer. When it comes to watering any plants there are lots of factors to consider that’ll make the amounts and regularity vary. I’ll go over all those factors so you can see what will be the best for your own situation.
It sounds like it is not getting enough light. Repotting once per year after blooms have dropped is a good thing. Use a high quality bark mix for orchids or high quality sphagnum moss. If the flower spike dried out you did exactly the right thing by removing it. So try more light without direct sun and be sure to water only if the mix is dry. No wet feet for most orchids. Good luck
If you are growing your orchid in tree bark or another well-draining medium, you should provide copious amounts of water to soak the roots. After soaking the potting mixture well, allow the excess water to drain out of the pot. This will ensure the return of that all-important airflow to the roots as well as flushing the growing medium to prevent the buildup of mineral salts. Just be sure that you never leave the roots soaking for more than about 15 minutes, as they will start to become waterlogged if you do.