7800 Greensand Filter Installation & Startup Guide
Page 5
www.cleanwaterstore.com
Rev 120214
4.
If you will be using copper piping, do not sweat the copper pipe directly on to the 7800 control
valve. Avoid heating up the 7800 control valve plastic with the torch.
5.
You do not need unions to install your 7800 control valve. If you need to remove it, the 7800
has quick-release couplings that make it easy to put the Greensand filter on by-pass and remove
the filter system from the piping.
6.
The drain line tubing (not supplied) is connected to a drain from the drain outlet using flexible
½” ID tubing. Note that the drain can run up above the 7800 control and into a drain, it does not
have to drain down, as the filter backwashes under line pressure from your well pump. Most
plumbing codes require an air-gap connection, so that if your sewer or septic tank backs up, it
cannot cross connect with the drain tubing.
How Your Greensand Filter Works
See Fig 1. In greensand iron filter, the water enters the top of the tank and flows down through the
media and up the distributor tube. Iron and manganese in the water turns to an oxidized particle upon
contact with the media and is trapped in the media. During backwash, the water flow is reversed and
water flows down the distributor tube and up through the media, lifting and expanding the greensand
filter media, and removing all the iron and rust trapped in the filter. After the backwash stage,
potassium permanganate solution is automatically drawn in from the potassium permanganate solution
tank and slowly rinses through the greensand filter for 1 hour, and then the greensand media is
thoroughly rinsed-to-drain. This entire automatic process, called ‘regeneration’ takes about 90 minutes.
Typically the greensand filter is set to regenerate every 3 to 7 days, during the middle of the night when
no water is being used.
Fig 1 - Greensand Filter Tank Water Flow
