feat: wip

Sources/PressureEstimationsFeature/EquipmentSettingsForm.swift

@@ -42,10 +42,20 @@ public struct EquipmentSettingsForm {
       self.ratedStaticPressures = .init(staticPressures: sharedSettings.equipmentMetadata.ratedStaticPressures)
     }
     
+    private var equipmentTypeValidation: Bool {
+      guard equipmentType == .furnaceAndCoil else { return true }
+      return sharedSettings.heatingCapacity != nil
+    }
+    
+    private var filterDropValidation: Bool {
+      guard includesFilterDrop else { return true }
+      return sharedSettings.manufacturersIncludedFilterPressureDrop != nil
+    }
+    
     public var isValid: Bool {
-      guard equipmentType == .furnaceAndCoil 
-      else { return ratedStaticPressures.isValid }
-      return ratedStaticPressures.isValid && sharedSettings.heatingCapacity != nil
+      ratedStaticPressures.isValid
+      && equipmentTypeValidation
+      && filterDropValidation
     }
 
     // Note: These need to be in display order.