Main drains are usually located at the deepest part of a pool. Water is sucked through the drain to the pump and circulated through the system. There is typically one main drain for a residential in-ground pool, and that main drain usually has one port that feeds a pipe to the pump. When the pump is on, water is sucked from the pool through the main drain and skimmer. Inside a spa or hot tub, there might be several ports feeding pipes to different pumps that make different types of water jet action.
There should be no changes to the main drain’s size or location unless it is evaluated by the engineer or pool expert who designed the installation.
The main drain, which is located on the pool floor, might have a special hydrostatic port. This type of port is a one-way port that allows water that collects underneath the pool floor to enter the drain, which prevents water from leaking out of the pool. If water collects underneath a pool, extreme upward pressure may be created that could crack the pool. This pressure is called hydrostatic pressure.
In some pools and spas, there might be more than one main drain. If one drain is clogged or blocked with a hand or foot, the other will be open and water can be pulled from that drain instead. This helps prevent injuring the person who is blocking the main drain. If the main drain is located on a pool floor that is very deep, this safety suction line might not be necessary. At any pool, there should be a balance of suction at the main drain and the skimmer to prevent injuring someone who might be blocking a port.
Some drains can cause a whirlpool effect. For these drains, which are typically located in shallow pools, a special domed cover could be installed at the main drain to prevent this action. Otherwise, the main drain at the deep end of the pool will have a grate installed on it. The cover might be flat with grated openings. The drain is usually 6 to 12 inches in diameter.
The main drain should be visually inspected regularly (ideally, daily), particularly when the pool is being serviced or when the pool floor is being swept. There shouldn’t be any damage, clogging or cracks at the drain cover.
It is important to minimize the flow through the main drain to prevent entrapment problems. Local codes regulate the water flow-rates through the system.
Recent Comments