Series RFS-4000 is a line of general purpose proving switches designed for HVAC and Energy Management applications. These switches can be used to sense positive, negative, or differential air pressure.
DESCRIPTION & OPERATION
The plated housing encloses a diaphragm, a snap-acting switch, and an optional calibration spring (in adjustable set point models). The sample line connections located on each side of the diaphragm accept rigid or flexible tubing. Various electrical connections are available. An optional enclosure cover
can be provided to protect the operator from accidental contact with the live switch contacts. The enclosure cover accepts a 0.5″ conduit connection.
Select a mounting location which is free from vibration. The Series RFS-4000 must be mounted with the diaphragm in any vertical plane in order to maintain the specified operating set point. Avoid mounting with the sample line connections in the “up” position. Refer to Figure 1. The standard model is surface-mounted via the four 3⁄16″ wide slots on the zinc-plated strap bracket.The mounting slots are 3-7⁄8″ apart. Custom mounting configurations are available.
AIR SAMPLING CONNECTION
Series RFS-4000 switches are equipped with sample line connections situated on either side of the diaphragm as shown in Figure 2. These connections are suitable for either rigid or flexible tubing. Locate the sampling probe a minimum of 1.5 duct diameters downstream from the air source. For sample lines up to 10 feet in length, ¼”OD tubing is acceptable. For lines up to 20 feet,use ¼”ID tubing. For lines up to 60 feet, use ½” ID tubing. Install the sampling probe as close to the center of the airstream as possible. Refer to Figure 2 to identify the high pressure inlet (H) and the low pressure inlet (L). Select one of the five application options listed below, and connect the sample lines as recommended.
POSITIVE PRESSURE ONLY: Connect the sample line to inlet H; inlet L remains open to the atmosphere.
NEGATIVE PRESSURE ONLY: Connect the sample line to inlet L; inlet H remains open to the atmosphere.
TWO NEGATIVE SAMPLES: Connect the higher negative sample to inlet L. Connect the lower negative sample to inlet H.
TWO POSITIVE SAMPLES: Connect the higher positive sample to inlet H. Connect the lower positive sample to inlet L.
ONE POSITIVE AND ONE NEGATIVE SAMPLE: Connect the positive sample to inlet H. Connect the negative sample to inlet L.
Before pressure is applied to the diaphragm, the switch contacts will be in the normally closed (NC) position. Wire control and alarm functions as shown in Figure 3.
The adjustment range of a standard Series RFS-4000 Air Switch is 0.15±0.02″ wc to 2.0″wc or 0.15±0.02″ wc to 5.0″wc.
SERIES RFS-4000 AIR PRESSURE SENSING SWITCHES
Mount with the diaphragm in any vertical plane.
Standard Set Point Ranges:
• 0.15 ±0.02″ wc to 2.0″ wc.
• 0.15 ±0.02″ wc to 5.0″ wc.
Field Adjustable “Operate Ranges”:
• 0.17″ wc to 2.0″ wc.
• 0.17″ wc to 5.0″. wc.
Field Adjustable “Release Ranges”:
• 0.10″ wc to 1.9″ wc.
• 0.10″ wc to 4.7″. wc.
Approximate Switch Differentials:
• For 2.0″wc set point range: progressive, increasing from 0.05±0.02″ wc at minimum set point to approximately 0.1″ wc at maximum set point.
• For 5.0″wc set point range: progressive, increasing from 0.05±0.02″ wc at minimum set point to approximately 0.3″ wc at maximum set point.
Air or combustion by-products that will not degrade silicone.
½ psi (0.03 bar).
Operating Temperature Range:
–40 to 180F(–40.0 to 82.2C).
100,000 cycles minimum at ½ psi maximum pressure each cycle and at maximum rated electrical load.
300 VA pilot duty at 115 to 277 VAC;
15 amp noninductive to 277 VAC, 60 Hz.
• ¼”, 90° quick-connect terminals.
• Screw terminals with cup washers.
Sample Line Connectors:
• Externally threaded 7⁄16″ -24 UNS 2A or 7⁄16″ -20 UNF 2A thread with nuts and self-aligning ferrules.
• ⅛” – 27 NPT female connectors.
• ¼” – 18 female thread in combination with ⅛” – 27 NPT female connectors.
• ¼” slip-on connectors.
• Tri-barb connectors for ⅛”, ¼”, and 5⁄16″ ID tubing.
UL, CUL, CE. CSA pending.
< 1 lb.