Replacement Weir Door Flaps for skimmers. The weir door seems like such a simple insignificant component but is so important for optimal performance on a skimmer especially on a pond that suffers from a lot of wind blown debris. If your skimmer weir door is busted up, bring the performance back to your pond skimmer with a new weir flap. We stock the most commonly replaced skimmer weir door flaps here in our online store. I you are in need of a weir door you don't see listed here. Please call our headquarters Toll Free at 1 (800) 522-5043 and we will help you get what you need.