Pool Info: Backwash Valves - Page 2


Backwash Valves

Example of a MPVMultiport valves usually have 6 positions (Some Jacuzzi valves have 7 and some American valves have 8). The positions are usually labeled: Filter, Backwash, Rinse,Example of a Multiport Valve Recirculate, Closed and Drain/Waste. These are described below in more detail.

When you move the multiport valve from Filter to Backwash, (always shut pump off first) you are reversing the direction of water into and out of the filter. This is where we get the word "back-wash", from sending the water backwards thru the pool filter tank during backwashing.

How Long do I backwash my filter for?

Backwash until the water runs clear out the waste line. Usually about 2 - 3 minutes. You may need to add water to the pool before or after backwashing. On a D.E. filter, the last step is to add the fresh D.E. powder to the filter, through the skimmer. Also effective with D.E. filters is to backwash 2 or 3 times, for a total of 5 mins. Backwash for 2.5 mins, filter for 20 secs, Backwash for 1.5 mins, filter for 20 secs, Backwash for 1 minute, then back to the filter position. This removes more DE powder than just a single backwashing.

When do I need to Backwash?

When the pressure gauge indicates a pressure rise of 8 - 10 lbs above the clean, or start-up pressure, when flow rate is significantly reduced. Always shut off the pump first before turning a multiport valve handle.

What Maintenance do I need to do for my Multiport Valve?

There really is no maintenance on a MPV. Just make sure to winterize properly if you are in the snowbelt.

Help! My Multiport Valve leaks out the waste line all the time!?

You most likely have "blown a gasket". Remove the lid and handle assembly from the valve body and inspect for warped or damaged spider gaskets.

Help! My Multiport Valve leaks out the top cover all the time!?

Beneath the multiport lid, there are several washers, a spring to give tension to the handle, and someExample of 2 MPV stem o-rings on the stem that connects to the handle. One or more of these may need to be replaced. You can also purchase a Key Assembly, which is every-thing that comes out of the valve body when you remove the cover screws and lift it out by the handle. You can view a schematic of your filter backwash valve in our valve parts department.




  1. MULTIPORT VALVE COVER POSITIONSFILTER: Keep it here 99% of the time, except when backwashing, rinsing or wasting.

  2. RINSE: Use this setting for about 20 seconds after backwashing to rinse tank.

  3. RECIRCULATE: Use this if the filter's broken; at least you're circulating the water.

  4. BACKWASH: Use this setting to reverse the flow in the filter and send water out of the waste line. Make sure valves are open or hoses rolled out.

  5. CLOSED: Put here to close off flow from the pool, usually to work on the equipment. Do not operate pump with valve in closed position.

  6. WASTE/DRAIN: Another filter bypass setting (like Recirculate), but this setting sends the water out of the waste pipe (hose), instead of returning it to the pool. Used to lower pool water level or to vacuum to waste if vacuuming fine, silty debris or algae.


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