Pool Diverter Valves are generally installed in tight groups to save space in the pool equipment area. When one of these valves has to be replaced, there generally isn't enough flexibility in the pipes to cut out and squeeze in a standard diverter valve because of the 3/4" overlap required on each end of the valve. By using a Diverter Valve with unions, however, you can install the unions and drop in the valve between the unions without having to spread the pipes. Also, if you ever have to replace this valve again, you won't have to cut it out again, just loosen the unions, pull out the damaged valve and drop in a new one between the existing unions. This guide shows you how to replace a standard 3-way direrter valve with a Valve with unions.
BUY PARTS - Before you cut out the damaged Diverter Valve, you will want to order a new Diverter Valve with unions. The valve pictured here is a CMP 3-Way Valve with Unions, 1.5” Inside 2" Outside Clear CPVC
MEASURE COLLARS - When you attach each union end onto a pipe, the pipe can only be inserted part way into the union end leaving a portion of the end extending beyond the pipe. The length of this extension will also have to be provided for in the space for the valve. For this CMP 1 1/2 " valve the extension is 3/8".
DETERMINING FINAL SPACE - This picture shows the sum of what is considered in cutting a space for a new CMP 1 1/2 " valve: the valve - 5 3/4"; the left union end - 3/8"; the right union end - 3/8" for a total of 6 1/2". If you're unable to make straight cuts on your pipes (most of us aren't), I would add another 1/4" to this measurement making it 6 3/4" total. For the inlet port, provide half this distance or 3 3/8". Note these calculations are based on a CMP valve for 1 1/2" piping. They will vary with manufacturer and the size of the valve.
CUT OUT VALVE - If you have a 3-way Diverter Valve, you will have to cut each of the three pipes attached to the Valve. Per the calculations above, leave a space of 6 3/4" between the two output ports. Leave a space of 3 3/8" between the end of the inlet pipe and the center of the space between the two output pipes.
GLUE ON UNIONS - Glue the slip end of each union onto each of the three pipes. See our guide on " How To Glue Pool Fixtures Together" for instructions on gluing. Remember to PLACE THE COLLARS ON THE PIPES before you glue on the slip ends - threads towards the valve.