Specifications

HydroSense Soil Water Measurement System (CD620, CS620)

In December 2009, the rods were redesigned (see Figure 8-2).

Rods shipped prior to December 2009 had a disc-shaped collar

instead of a nut. The open-ended wrench is not used with the

older rod design; pliers are used instead. Because of this, the

open-ended wrench began shipping with the CS620 in December

2009.

NOTE

FIGURE 8-2. Newer CS620 rod design (left)

and older CS620 rod design (right).

The friction between the nut and the insert surface along with thread friction

will generally provide good rod attachment and loosening is unlikely. If rod

loosening does occur, a thread coating compound can be used to enhance

friction. There are two thread compounds that laboratory testing indicates

minimal effect on the HydroSense measurement.

A package with Loctite£ 222MS THREADLOCKER is included with each

CS620 probe. There is enough thread coating to treat several rods. The

compound should be used sparingly as a thick coating will cause slightly

higher measured water content values.

Another product that works well is Vibra-Tite by ND Industries. This

compound has a higher viscosity than most thread coatings and a narrow strip

is painted on the threads. The applied compound must cure aerobically before

the rods are threaded into the probe inserts. The cured compound is a resilient

plastic which is reusable several times. It is important that the rod threads are

not completely coated because this can affect response of the probe.

Replacement of the rods is a simple matter of screwing the threaded end of

each rod into the insert of the probe body with attention to the following

details.

x Threads should be clean before rod attachment.