Float Type Level Switches Installation and …

1 X-1 Visit for most current X30 AND MAINTENANCEF loat Type Level Switches Installation and MaintenanceOrientationA standard NPT female boss in tank top, bottom or side is all that is required for rapid Installation . Units operate normally in any attitude from the vertical to a 30 inclination with lead wires up or down. Standard IPS pipe extends units to any intermediate Level in the tank. Figure and RepeatabilityThe accuracy of many GEMS Level Switches is 1/8 ( mm) of true liquid Level . In order to assure the proper accuracy for your liquid, please specify the specific gravity of the media. GEMS will automatically calibrate for the submergence of the Float , based on this specific gravity information.

2 Furthermore, accuracy may be enhanced by specifying whether the circuit condition should be measured on decreasing or increasing liquid Level . The repeatability of the actuation point is approximately 1/32 inch (.79 mm).Moisture ProtectionWhen moisture exists in conduit and extension pipes, the potential for this moisture to wick down the wire leads and into the switch assembly exists. Should this happen, the switch may fail to close due to a high resistance path through the are several means that can be used to prevent this from Pitch conduit away from the Level switch when possible so that condensation will drip away from the Level switch assembly. Figure When a vertical run of extension pipe is used to extend a Level switch down from the top of the tank, a non-conductive silicone oil should be used to fill the vertical run.

3 Alternatively, an appropriate potting may be used to fill the vertical run to occupy the space in which condensation will normally form. Figure working closely with your GEMS representative, there are many design considerations that can help lessen the effects of Consider a product such as the GEMS LS-270 Single Level Switch which has a water-tight molded Consider using a unit with a connector and gasket Consider using moisture resistant heat shrink tubing on the switch capsule Consider using Scotchcast 2114 sealing compound and electrical insulator. Part No. WORD OF CAUTION: Most of GEMS Level products incorporate a potting cap or are fully potted. Due to the bonding characteristics of the potting to the wire leads, there is no way of assuring a water tight seal at the potting joint.

4 Our potting cap will resist moisture to some degree, but the precautions mentioned above should be used to assure moisture doesn t enter the switch and cause a 1 Figure 2 Figure 3 Please refer to Gems Instruction Bulletins for detailed Installation and maintenance procedures. Instruction Bulletins are available at for most current XNPT1/8 1/4 1/2 3/4 1 1-1/4 2 3 T .39 .53 .55 .68 .71 .76 LACTUALTANKINTRUSIONA(21/32 )L(1-3/16 )1T1/4 NPTFLUIDLEVELL0 LACTUALTANKINTRUSIONA(1-1/4 SHOWN)L1(6 SHOWN)L0T1/2 NPTFLUIDLEVELACTUALTANKINTRUSIONLP(1 SHOWN)T1 NPTL0 FLUIDLEVELL1(6 SHOWN)Thread Treatment SealingWhen threading metal threads into a metal coupling, pipe sealant or Teflon tape is recommended.

5 Due to potential compatibility problems, when sealing plastic threaded units, a compatible pipe sealant such as No More Leaks from Permatex is threading a plastic Level switch into a metal coupling, the installer should use a suitable wrench and tighten the threads 1 to 1-1/2 additional turns past hand tight. Over torquing of the threads will result in damage to the plastic mounting Effect of Thread Engagement on Actuation PointsThe length of mounting threads engaged at Installation is important in calculating switch actuation points and the actual length of stem extending into the tank. Use the chart below to find the thread engagement length (T) for a given NPT size. Factor the T dimension into any calculation of switch actuation levels (L) and overall length (LO).

6 Examples: To solve for L use the formulas shown in the examples below. To calculate the Actual Tank Intrusion, substitute the LO value in place of L1 in any of the Mounted Standard LengthLS-1900 Series internally mounted through a 1/4 NPT hole. To calculate L dimension:L = L1 + (A - T)L = 1-3/16 + (21/32 - .39 )L = Internally Mounted Configurable LengthLS-800 Series (Type 1) internally mounted through a 1/2 NPT hole. To calculate L dimension:L = L1 + (A - T)L = 6 + (1-1/4 - .53 )L = No More Leaks is a trademark of Permatex Industrial Corp., a subsidiary of Loctite is a registered trademark of DuPont of Variables Used in Examples BelowA = Mounting = Thread = Distance from coupling (bung) top to inside surface of tank or = Switch actuation Level as measured from inside surface of tank or bracket to fluid = Switch actuation Level , nominal, as measured from bottom of mounting (based on a liquid specific gravity of ).

7 Externally Mounted Configurable LengthLS-700 Series (Type 3) externally mounted through a 1 NPT hole. To calculate L dimension:L = L1 - (P - T)L = 6 - (1 - .68 )L = THREAD TREATMENTM"(Visit for most current :C9>M MINDUCTIVELOADREEDSWITCH(DRAIN THE LOAD)1N4004 INDUCTIVELOADREED SWITCH(PROTECT THE SWITCH)HNG::9 HL>I8= EGDI:8I>DCReed Switch ProtectionThe hermetically-sealed reed switch used in GEMS Level Switches are extremely rugged and designed to operate reliably for many years 2 million cycles under ideal conditions. To achieve the maximum service life, reed Switches benefit from protected electrical :s $ON T BE MISLED BY THE RESISTIVE RATINGS OF THE Switches -OST APPLICATIONS INVOLVE inductive $ON T BE MISLED BY THE WATTAGE RATINGS OF LOADS ,OW WATTAGE LOADS ARE OFTEN HIGH inductive devices, making contact protection very Protection RequirementsWhen switching inductive loads such as relays, solenoids and transformers, reed switch contacts require protection in order to ensure long, dependable life.)

8 When current is interrupted, the inductance or electrical inertia of the load generates a large high frequency voltage, which appears across the switch contacts. If the voltage is large enough, it can break down the medium in the gap between them, making a conductive path. This phenomenon, called arcing, is the spark you see. Arcing can cause the contacts to burn, weld together or stick; thus, giving unreliable performance. The purpose of protection circuits is to prevent arcing, by shorting this voltage through an alternate 1N4004 diode (or equivalent) connected cathode-to-positive, as shown in Figure 1, is recommended. The diode does not conduct when the load is energized, but conducts and shorts out the generated voltage when the switch opens.

9 The generated voltage always acts in series with the applied resistor and capacitor, connected in parallel with the switch, as shown in Figure 2, is recommended. The capacitor is a high impedance to 60 hertz, but is essentially a short circuit to high frequencies of generated suppressors or varistors may also be used to dissipate the transient and protect the switch contacts. Notes: $ONgT BE MISLED BY LOW VOLTAGE b10V, low current b1MA type of loads. These loads may require special gold plating on contact surfaces to operate reliably at these low voltage/low current levels . For long term reliable low current switching action, Gems 20VA Switches should be operated at a minimum of 12V to assure contact make; , break through an oxide film which may form over long periods of Incandescent lamp loads are very destructive to reed switch applications.

10 These type of loads have a 6-10 time the normal operating current (inrush current) when first energized. This high current Level is a prime factor which decreases the life of the The following rating may be used for = 130 volts Energy = 30-50 joules Peak Amps = 4000-6000 The dependable reed switch is at the heart of most Level switch shown in this 1 $ # #ONTACT Protection $RAIN THE ,OAD Figure 2 ! # #ONTACT Protection (Protect the Switch)100 7 7!44 F 6/,4 Gems Sensors available reed-switch protection parts: 134579: has parts for DC (diode) & AC (varistor network) circuits in it 134580: has parts for AC ( network) circuit in it 59690: recommended really only for DC applications as the transient varistor can short out over time if used in an AC circuit M"*Visit for most current :C9>M DataStandard reed Switches in GEMS Level and flow switch units are hermetically-sealed, magnetically actuated, make-and-break type.