How to Replace a Switch Module on a Plastic SureSite
The below information will help explain how to replace or add a Switch Module on a Plastic SureSite. SureSite switch modules are clamped onto the housing so they can easily be removed, added, or the position adjusted.
First step is to identify what type of switch module you have or would like to add. There is a Standard, High Temperature, and Explosion Proof versions. Standard switch modules are rated to 300 F, High Temperature switches are rated to 750 F, and Explosion Proof switches can be placed in a hazardous location with the proper conduit, and are also rated to 750 F. See below.
Below shows the various switch type p/n’s available for a Plastic SureSite. Select your switch based on the temperature/ hazardous rating requirement, and the switches logic (SPST, SPDT, DPDT).
After determining what type of switch module you want to add or replace, take a picture of how it is positioned on the SureSite housing because this will determine the switches logic. The logic of the switch is determined based on the position of the lead wires/conduit connection. With the lead wires up the switch will close on rising level, which is typical for a High Alarm. With the lead wires down the switch will close on falling level, which is typical for a Low Alarm. See below diagram.
One last step before removing the switch is to also note the orientation of the switch module. As mentioned earlier all switches must be 180 degrees (opposite side) from the flag assembly. See below diagram.
After you have determined the orientation and the logic your switch is in, you can remove the old one from the housing by loosening the clamp. Switch modules work off reed switches, but they also have biasing magnets within them to make sure they remain in an open or closed state until the float and magnet return. Therefore, it is important to not use a strong magnet when testing your switch module. A strong magnet can damage the reed switch and/or biasing magnet. See “How to Test a Plastic SureSite Switch Module” for more information.
Before installing your new switch module back onto the housing, make sure it is in the correct logic. For example, if you’re using it as a high alarm, you want the lead wires up and you also want to make sure the switch is open (if the level is beneath the switch at the time of installation). If you need to adjust the switch (from open to closed) you can use a spare float or take the float out of your SureSite. You may also use a small pencil magnet with a Gauss rating of around 1100 (+250 / -100). Ensure it is within that Gauss rating otherwise you risk damaging the switch module.
In order to position your switch module at the correct level its important to understand where the reed switch is within the switch module. The reed switch will be located near the middle of the switches. See below for approximate location.
Lastly, slide the switch clamp between the flag assembly and the housing, and tighten the clamp screw securely, not to exceed a torque of 120 lb-inches.
Refer to the Switch Modules Instruction Bulletin for further information.