Stop pump and release all pressure from system.
Make sure that the gasket groove is free of water, grease, oils, debris and parts of the old gasket. Use NON-acetone finger nail polish remover to remove any gasket residue. Make sure the remover is NON-acetone or it will melt the plastic. Please note that not all multiport valve gaskets are glued in. If the gasket on your valve isn't glued, you would bypass Step #6.
NOTICE: Once this step is started, continue through Step 10 without interruption. Using an Adhesive For Valve Seat Gasket apply glue sparingly (a bead about 1/16" wide) to the bottom only (not the sides) of the spider groove in the valve body. The glue lines must be continuous and intersect at the intersections of the grooves.
Minimum cure time is 2 hours. Curing for 24 hours is recommended for full strength.