Pentair WATER SOFTENING SYSTEM 1.0 - Page 9

WHOLE HOUSE WATER SOFTENING SYSTEM • 9
Special Attention for situations where a Filter and a Softener are installed together:
When a whole house filter and a softener are installed side by side, the preferred approach is to run a sepa-
rate drain line from each unit all the way to the point of termination. If this is not done, there is the potential
for drain water from the filter to back feed through the softener and overfill the brine tank, especially when
drain lines are run overhead. (Please note that back feed goes only into the brine tank, not the service line.)
If circumstances require you to tie the drain lines together, please use one of the following methods to
avoid back feed issues:
Option 1: Run the drain lines from both systems to the point of termination, and tee them together before
the air gap. (See figures below)
Option 2: Install a PVC check valve with a light spring on the Softener side to prevent back flow to the
Softener. (See figure below)
FILTER
SOFTENER
SPRING CHECK ON DRAIN
LINE AFTER SOFTENER
WATER IN
TREATED
WATER OUT
TO APPROVED DRAIN
LOCATION WITH AIR GAP
WATER IN
TREATED
WATER OUT
2 SEPARATE DRAIN LINES
TO APPROVED DRAIN
LOCATION WITH AIR GAP
FILTER
SOFTENER
2 SEPARATE
DRAIN LINES
AIR GAP
APPROVED FLOOR DRAIN
TEE