This guide is an expansion on the first Multiport Valve operations guide. It explains how the top part of the valve actually diverts water to each of the ports. To have a better understanding of this guide, read the first guide on "How a Multiport Valve Operates" before you read this one. This guide is based on the operation of a Hayward Valve with 7 settings but the concepts discussed are applicable to most multiport valves.
When you unscrew the 6 screws on top of the multiport valve, the valve separates into the two subassemblies shown here: the Valve Body and the Handle Assembly (shown upside down). The Valve Body stays stationary while the Handle Assembly rotates above it to direct water from the pump to the other ports.
This picture identifies the different ports and levels of the multiport valve. Water from the PUMP enters the valve at level 1 and is diverted to one of the other ports in level 2 by turning the Handle Assembly. The RETURN port returns the water back to the pool; the WASTE port send the water out the waste hose; TOP directs the water into the top of the sand filter; and PIPE directs the water to the bottom of the sand filter.
This is the bottom of the Handle Assembly and what you are seeing in the Spider Gasket, the source of many multiport problems. When intact, the gasket keeps water from flowing into the wrong ports. Water comes in from the Pump port (level 1). The pie pieces marked with X's are closed off. The function of level 2 will be shown later but it is key to understand that any water that comes into the valve at level 2 can flow into any other port that is open in that half of the circle.
This is a picture of the Valve Body looking down into it showing the location of all the ports. Water will come in through Port A on Level 1 from the pump. The Handle assembly, discussed above, will direct the water down to Level 2 into B-RETURN, C-WASTE, D-TOP, or E-PIPE depending on what mode the Handle is set to.
In this picture the two simplified pictures are superimposed on each other. This shows how the two pies interact when the valve is placed in the RECIRCULATION mode. The heavy black lines show the positioning of the Handle Assembly; the red lines represent the Valve Body pie. In this case water comes in from the pump (green) at level 1 and is directed to the return port in level 2. In this setting there is no other opening for the water to go. All other ports are closed.
This picture shows how the two pies interact when the valve is turned one position clockwise to RINSE mode. As before, water comes in at level 1 from the pump, is directed down through the top of the filter, goes through the filter, where it is collected and sent back up the pipe (yellow) to level 2 of the valve. In level 2 of the valve the water passes over the closed section to be released though the Waste port.
Turning the valve one more position clockwise to FILTER - water comes in at level 1 from the pump, is directed down again through the top of the filter, goes through the filter, where it is collected and sent back up the pipe (yellow)to level 2 of the valve. In level 2 of the valve the water goes over to and out the Return port.
Turning the valve clockwise to the final position, BACKWASH - water comes in at level 1 from the pump, is directed down this time through the pipe to the bottom of the filter tank, where it is forced up through the sand to the top of the tank and into level 2 (yellow). In level 2 of the valve the water flows over to and out the Waste port.