Pentair THS Series Installation And User Manual page 45

The semi-automatic controller consists of a single gauge panel with gauges to
measure influent and effluent pressures, water pressure supplied to the multiport
valve, and the multiport valve knob, which is used to actuate the valves.
The influent and effluent pressure gauges show the water pressure coming into
and out of the filter system. This information will be useful in determining when the
tanks need to be backwashed. The influent pressure should always be higher than
the effluent. If it is not, please refer to the troubleshooting section of this manual
for assistance.
The multiport pressure gauge shows the water pressure supplied to the multiport
valve. This gauge should read at least 35 psi for proper valve operation. The
water supplied to the multiport valve is what actuates the diaphragm valves. If
insufficient water pressure is supplied, the valves may not actuate fully. This can
lead to insufficient backwashing of the sand bed, which will diminish the
effectiveness of the filters.
The multiport valve knob is what is used to initiate the backwash cycle. On it there
will be numbers, which correspond to the tanks, and the word home. When turned
to position 1 it will backwash tank one. If there are 2 tanks in the system then
position 2 will be used to backwash tank two. The home position is for use in
normal filtration mode.
Switching to Backwash Mode
The following are the steps to follow to initiate a backwash cycle with a semi-
automatic controller. This can be used for both single and dual tank systems.
NOTE: Before actuating the multiport valve, it is recommended that the filter
feed pump be turned off. Make sure all isolation valves to the feed pump are
in their open position.
STEP 1: Rotate the multiport
valve to position 1. This actuates
the diaphragm valves. The
pressure reading on the multiport
pressure gauge will drop as water
is allowed to flow into the tops of
the valves via the 3/8" polyethylene
tubing.
Diaphragm Valve Face Piping Kit Installation Manual
5/31/12
Pg. 44 of 52
Rev. F