Pentair FLECK 2750 NXT Installer Manual page 45

• 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 is connected to the tank, or on the female thread connection of the
tank. In some cases, damage may also be seen on the valve inlet and outlet connections;
• in any case, any failure caused by improper installations and/or piping connections may void
the warranty of Pentair products;
• in the same way, using lubricant* [
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 used (especially Noryl) will highly suffer from contact with this
type of grease, leading into structural damage hence to potential failures.
Ref. MKT-IM-026 / C - 15.12.2020
Page 45] on the valve thread is not allowed and will void
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Installer manual Fleck 2750 NXT/NXT2 - Installation
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