Recently installed a new Ultramax with the G-Max fill valve. Initially the tank filled to the very top of the flush tower / overflow tube and you could hear and see the water running over the top and down to the bowl. Adjusted the fill valve so that the water stops at the line on the fill tube that is about 1/2" below the top. Everything appears fine after the flush. Water stops at correct level and the bowl fill line shuts off. After 5 to 10 minutes, water starts dripping out of the bowl fill line and must also be coming out of the fill valve because the water slowly rises in the tank until it is weeping over the top of the overflow. (Takes between 30 and 60 minutes to reach top of overflow, haven't really timed it)
Fill valve is not the "Korky" type shown in several posts but is flat on the top and says G-Max. Is this unit serviceable like the Korky valve or do I need to contact the retailer and get a new valve? If it is servicable, a diagram would be nice if available.