membership upgraded.

We seem to have different sets of common problems each year. This year, problems with low pressure on various multiport valve positions seem to be common. Unfortunately, there are many possible causes, and we can only do a little to help -- most of the work, checking for possible problems, has to be done by YOU.

If you'd like us to help, we'll need pump, filter, and multiport valve make and model; pressure readings with pump off, pump on and filter in recirculate, pump on and filter in filter; and ideally, pictures using Picasa, Webshots, Flickr, etc. to post.

Also, you'll need to say what you mean by having "no pressure" when you are in these positions. Pool owners often confuse pressure and flow. Do you mean that, when you backwash, your pressure gauge shows a low pressure? Or do you mean that when you backwash, the pressure gauge isn't that low, but that there's very little flow out of the discharge pipe?

If you mean the second, look for a valve or restriction on the discharge line.

Good luck!