Typically you only need to backwash when your filter's PSI is double its starting PSI level. For example, mine starting PSI is between 7 and 12, so when it gets to between 15 and 20 PSI I'll backwash.
1 is waste 3 is backwash 4 is normal
It should be on filter and don't forget to backwash at least once a week.
No, backwashing is used during the cleaning of the sand, when the pressure has gone up on the filter, or you feel the vacuum is not doing its job that is when you should backwash.
No , if you have a D.E. filter instead of an older cartridge filter than the D.E. can get pretty messy if when you filter clean , and if you have a backwash when you backwash .
There wont be any dirt under the sand. When you vacuum your pool you should do it on filter mode Otherwise you will lose a lot of water for nothing, this would be especially wasteful in the case of a salt water pool. Ofter having vacuumed the pool on filter mode and if the pressure gets too high backwash. after backwash rinse for a minute, then return to filter.
how do i calculate the volumn of backwash in a pool
Same as any sink. The vacuum breaker installs in the backwash unit. Just plumb in hot & cold, and plumb out a drain line.
It sounds like either your valve is not set completely to "filter" or your valve's seals are degrading. If the valve is completely set to "filter", then either replace the valve, or plug the end of the backwash hose.Here's a good place to look for new backwash filters: http://www.swiftpoolsupplies.com/category/product-list/backwash-valves
The "backwash knob" - usually called the handle - is located on top of the filter or just to the side of the filter on a sand filter. They could be on the very bottom of the filter or to one side of the filter but never on the pump. The filter is the large tank.
If dirt returns to the pool while you are vacuuming, it means there is a hole or broken item in the filter. If filter is a cartridge filter the could be a hole in the cartridge. DE filter, hole in filter fabric or broken plastic manifold. Sand filter - broken plastic fitting maybe.
Take the cartridge out and hose it off
Filter, winter, closed, backwash, rinse, waste