Valves & Unions For Installing Swimming Pool Equipment
The valves and unions that you use to install your swimming pool equipment will have an impact on the functionality and serviceablity of your system. Valves allow you to regulate the flow in your system, isolate parts of the system, as well as zone in peripheral devices in a parallel branch as opposed to in series. (in series is in-line and parallel is off-line). Unions (and union valves) allow access to open the plumbing system quickly and easily for repairs, modifications and winterizing.
Schedule 40 thickness valves are white and schedule 80 thickness valves are dark grey - the same as for pipe fittings
This is a 1.5" union (slip x slip). These are used for creating access points in your plumbing system to open for service or winterizing. Placing a union near threaded connections can also help to reduce leaks. If the threaded connection develops a leak you can simply open the union, spin the threaded connection a 1/2 turn tighter, and put the union back together. For 2" pipe size use a 2" PVC Union
This is a 1.5" gate valve sometime called a knife valve, which is often used in hot tub applications where there is very little room to work with. While this style of valve allows for control in the smallest of spaces they are not commonly used on swimming pool installations. Ball valves are much more common for swimming pool equipment. For 2" pipe use a 2" PVC gate valve
Part number 9122 - This is a ball valve without unions. This valve represents one of the lowest cost ball valves that you can purchase for your pool. This valve is not serviceable as it has no unions, and the handle itself is usually very difficult to turn. This is something inherent in the design as most of these valves are very tough to turn even when brand new. For 2" pipe you would use a 2" PVC ball valve
Jandy offers a non-union valve option also which is more expensive than the 9122 model. Part number 9704 - As an installer I would strongly encourage you to consider a single union ball valve in place of this style. For 2" pipe use a Jandy 2" PVC ball valve
Part number 6114 - This is a single union ball valve which is the most common ball valve to be found on swimming pool equipment. This style valve is easy to open and close and has a union nut for opening the system during repairs or winterization. For installations below the water level of the pool this valve would be installed with the permanent end towards the pool and the union side towards the equipment. This would allow you to close the valve and open the union while the pool is still full. If you prefer the name brand option then Praher is also a major supplier for union ball valves and offer part number 150-010 - Single Union Ball Valve as a slightly more expensive option. For 2" pipe you would need a 2" PVC Single Union Ball Valve
Dual union ball valves like this one, part number 3622015W, provide the most control and serviceability of any type of ball valve. This style lets you have the ability to isolate and open the system in either direction from where the valve is installed.
This is a Hayward dual union ball valve, part number QTA1015CSEG, which is a compact style valve. This would be the entry level into the dual union valves and also comes with both slip and FPT connectors. For 2" pipe use a 2" PVC Compact Ball Valve
This is a Hayward true union (dual union) ball valve, part number TB1150STE, which is more common than the space saving Hayward dual union valve shown above. If you are on a tight budget there is a Cheaper 1.5" True Union Ball Valve option as well as a Cheaper 2" True Union Ball Valve. For 2" pipe, this is the Hayward 2" True Union Ball Valve
There are a few different kinds of check valves (one-way valve) such as spring check, swing check (flapper check) as well as ones that combine both swing and spring in one valve. A check valve should be installed in front of the pump on systems located above the waterline of the pool as well as in between a heater and any form of chlorinator (salt, erosion feeder etc.) This is a 1.5" Check Valve and has only a swing check (no spring). This can be mounted vertical or horizontal but be sure to observe direction of flow and location of the swing flapper. If you prefer a name brand valve like Spears then consider a S1520-15 Swing Check Valve For 2" pipe you can use the less expensive 2" Swing Check Valve or stick with the name brand Spears 2" Swing Check Valve
This is a swing & spring 1.5" Combination Check Valve swing & spring combination check valve. Spring valves are rated by the amount of force it takes to open the spring. This valve requires 0.5 lbs of force, which is to say very little force, which ensures the valve seats closed well due to the small amount of negative force applied to the flapper from the spring. For 2" pipe use a 2" Combination Check Valve
This is a Waterway 1.5" Serviceable Check Valve. The advantage of this style is it allows you to open and clean / service the valve as needed. Even a tiny amount of debris inside a check valve is enough to prevent it from operating properly. This valve uses a stainless steel spring and flapper system to ensure water can not travel backwards through the system. For 2" pipe use a 2" Serviceable Check Valve
This is a Pentair Check Valve which is a higher quality brand than most others. This check valve is serviceable, made from CPVC, and has 2.5" slip ports and 2" spigot ports. This means that if you wanted to use this valve with 1.5" plumbing you would need to also have two 2" Spigot x 1.5" Slip Reducer Bushings
Jandy is well known for creating High Quality Check Valves that are very commonly used in the pool industry. While they may be slightly more expensive than other models you can be sure that you are using a quality product. Typically speaking you only install check valves where they are needed and a failed check valve is likely to cause damage to a pump or heater, or possible cause a flood. Check valves are not something to cheap out on. This valve also requires two 2" Spigot x 1.5" Slip Reducer Bushings to use this on 1.5" pipe.
Jandy also offers a 90 Degree Elbow Check Valve fitting. While not something that would be needed often, if you have a unique plumbing arrangement that requires a check valve 90 degree elbow, then this is the best option available. This valve is 1.5" slip (or 2" spigot) or you can also get it in a larger 2" slip (2.5" spigot) Jandy 7512 Check Valve
This is a Pentair 3-way diverter valve . This style of valve is very common on swimming pool and hot tub plumbing systems as it allows you isolate any one of three lines feeding into it. These valves are also used in shared pool / spa combo units and as part of plumbing bypasses for peripheral components such as salt water cells or solar heaters. This valve has 1.5" slip ports to glue 1.5" pipe into however the outside of these ports is also a spigot for 2" pipe and can be glued into a 2" slip connection.
As with the check valves, the 4717 Jandy 3-way valve is a recognizable name of quality in the pool industry. The never-lube style of these valves makes them very easy to turn and operate as well as being serviceable. This valve is 2.5" spigot or 2" slip so if you want to use this on 1.5" pipe you will need three 2" Spigot x 1.5" Slip Reducer Bushings
This is a 24 Volt Motorized Valve Actuator designed to rotate the three way valves as shown above via control from an automation panel. These are off-brand actuators that can be used for automating shared pool & spa valve assemblies.
This is the Pentair Motorized Valve Actuator . This is a high quality 24 volt 180 degree MVA (motorized valve actuator) with a wired connection to a control box or automation panel. These actuator valves are perfect for installing solar heating systems that can be connected to a solar controller.
The valves and unions shown on this page are only the tip of the iceberg in terms of the types, styles, sizes and connection ports available - not even counting the different manufacturers. Almost every type of valve on this page has a version from Hayward, Pentair, Jandy, Spears, Lasco, Praher as well as a dozen cheaper imitation brands. This information is intended to provide you with a frame of reference as to some of the more commonly used fittings for installing pool and spa equipment specifically.
Be sure to read all of the sections on how to install pool equipment to get a solid understanding of the materials you will commonly need to install pool and hot tub equipment.