AIR PRESSURE SWITCHES compatibles and interchangeable with every brand and version on field (on wall mounted gas boilers fan assisted version). They are supplied with an “L” bracket to meet the mechanical compatibility (for fixing) and free adjustable screw in order to make correct pressure setting.
Series NS2™ Air Flow Pressure Sensing Switches are designed with sturdy, contaminant-free construction, to provide low cost, high accuracy and reliability.
NS2 switches offer a narrowswitching differential and low set point tolerance over a wide operating temperature and set point range.They can be used to sense positive, negative or differential air pressure. Factory-calibrated set points are available from 15Pa to 2500Pa. The glass-filled polycarbonate body of the switch provides a high degree of stability and accommodates many sample line connector options.The high and lowpressure ports are color-coded for ease of identification. Port, bracket, and terminal orientations can be specified. The integral snap-acting switch mechanism (patent pending) is available in SPNO, SPNC, and SPDT terminal configurations. An optional bleed hole is available, as well as numerous standard and custom mounting brackets. Please consult Cleveland Controls about themany customfeatures we offer.
GENERAL DESCRIPTION & OPERATION
The glass-filled polycarbonate housing contains a sensing diaphragm and includes an integral snap-acting switch. Sample line connectors are located on either or both sides of the diaphragm to accept air sample connections. The electrical connection consists ofmale 90° quick-connect terminals.The snap action switch can be actuated by a pressure or vacuum air flow, or by a pressure or vacuum differential.
Various mounting brackets are available. Figure 1 shows two typical styles. Select a mounting location free from vibration. Mount with the diaphragm vertical, or at a custom angle. Specify the mounting position when ordering. Avoid mounting with the sample line connections directed upward.
The snap switch has 90° male quick connect terminals in 1/4” (standard) or 3/16” (optional) sizes. Before pressure is applied to the diaphragm, the switch contacts will be in the deactivated position as shown in Figure 2.
AIR SAMPLING CONNECTION
Series NS2 switches are available with many different types of sample line connections that accept a wide range of flexible and rigid sample line tubing. See Figure 3.
AIR SAMPLING METHOD
The High or Positive inlet (P1) is black and the LoworNegative inlet (P2) is gray. Connect the sample lines as follows:
POSITIVE PRESSURE ONLY: Connect the sample line to P1; P2 remains open to the atmosphere.
NEGATIVE PRESSURE ONLY: Connect the sample line to P2; P1 remains open to the atmosphere.
TWO NEGATIVE SAMPLES: Connect higher negative sample to P2; lower sample to P1.
TWO POSITIVE SAMPLES: Connect higher positive sample to P1; lower sample to P2.
ONE POSITIVE AND ONE NEGATIVE: Connect positive sample to P1; connect negative sample to P2.
Standard: fine silver.
Optional: gold alloy.
15Pa to 2500Pa
Max. Pressure Rating:
Standard diaphragm: vertical or custom angle. Consult factory.
-40°C to 90°C. (-40 to +190F).
Sample Line Connections:
Many configurations are available.
Air and byproducts of combustion that will not degrade silicone or polycarbonate.
Standard Silver Contacts:
SPDT, SPST Electrical load: 1/10 HP @120 to 277Vac; 28VA pilot duty @ 24Vac; 125VA pilot duty @ 120Vac.
SPST Electrical load: 5 Amps resistive @ 24, 120 to 277Vac.
Optional Gold Contacts: .15 Amp resistive @ 24Vac orVdc.
SPNO, SPNC, SPDT.
Standard quick-connect terminals: ¼” x 0.032.
Optional quick-connect terminals: ³/16” x 0.032.
UL, CUL, CE.