Pentair FLECK 2910 NXT - Page 39

Installer Manual Fleck 2910 - NXT - Installation
Ref. MKT-IM-002 / B - 23.05.2018 39 / 114
• The diagrams above illustrate how the flexible piping connection should be mounted;
• in order to adequately compensate the tank elongation the flexible tubes must be installed
horizontally;
• should the flexible piping connection be installed in vertical position, instead of compensating
the elongation, it will create additional stresses on the valve & tank assembly. Therefore this is
to be avoided;
• the flexible piping connection must be also be installed stretched, avoiding excessive length. For
instance 20 - 40 cm is enough;
• excessively long and non-stretched flexible piping connection will create stresses on the valve
and tank assembly when the system is pressurized, as illustrated in the below picture: on the left
the assembly when the system is unpressurised, on the right the flexible piping connection when
put under pressure tends to lift up the valve when stretching up. This configuration is even more
dramatic when using semi-flexible piping;
• failure to provide enough vertical compensation may lead to different kinds of damage, either on
the valve thread which connects to the tank, or on the female thread connection of the tank that
connects to the valve. In some cases, damage may also be seen on the valve inlet and outlet
connections;
• in any case, any failure caused by improper installation and/or piping connections may void the
warranty of Pentair products;
• in the same way, using lubricant* on the valve thread is not allowed and will void the warranty for
the valve and tank. Indeed using lubricant there will cause the valve to be over-torqued, which
may lead to valve thread or tank thread damage even if the connection to piping has been done
following the above procedure.
*Note: Use of petroleum-based grease and mineral based lubricant is totally forbidden, not only on the valve thread, since
plastics (especially Noryl) will highly suffer from contact with this type of grease, leading into structural damage hence to
potential failures.