White Rodgers 770-1 Dual Purpose Air Switch Installation Instructions
Contents
1. INSTRUCTIONS TYPE 770 1 AIR SWITCH With SPDT Switch Action Responds to Positive Negative or Differential Pressure The Type 770 1 has a SPDT switch that can be actuated by a positive pressure negative pressure or a differential of pressure These two features plus its field adjustable operating range give this control unmatched versatility on a wide variety of applications some of which are shown below TYPICAL APPLICATIONS PROCESS DRYING Switch monitors negative pressure to stop conveyor or process and provides alarm signal on fan failure ideal for bulk chemicats food processing grain drying POWER HUMIDIFIERS Switch permits unit to operate whenever there is proper air move ment REFRIGERATION EQUIPMENT Switch responds to pressure drop ELECTRONIC AIR CLEANERS Switch permits power to cleaner whenever blower of system is oper ating NATURAL DRAFT BOILERS Switch signals insufficient draft provides safety limit to stop firing on lack of draft starts again on across refrigeration coils to signal alarm condition or automaticatly ini tiate or terminate defrost cycle GAS FIRED UNITS Switch proves sufficient air flow be fore permitting gas valve to open and ignition to occur sufficient draft FORCED DRAFT BOILERS Proves operation of blower by sampling positive or negative pres sures for firing control and safety INDUCED DRAFT BOILERS Proves operation of I D f2. TIC PRESSURE PROBE MUST BE PERPENDICULAR TO FLOW FAN OPERATION AND TRUE AIR FLOW WITH VARYING AMOUNTS OF STATIC PRESSURE PROBE MUST BE PERPENDICULAR TO FLOW NEGATIVE PRESSURE INCREASES AS FILTER GETS DIRTY FILTER 3 WAYS TO PROVE FILTER ON POSITIVE PRESSURE POSITIVE STATIC PRESSURE DIFF ACROSS FLOW IS REDUCED INCREASES AS THE FILTER FILTER CHANGES AS FILTER GETS DIRTY AS IT GETS DIRTY GETS DIRTY LOCATION OF SAMPLE LINES FAN OPERATION OR AIR FLOW WITH NO STATIC PRESSURE SUCTION OR FAN OPERATION PROVE POSITIVE STATIC PRESSURE yl om PRESSURE CONVERSION TABLE 1 Water 0361 Ibs sq in or 0735 in Mercury 1 Mercury 13 6 in water or 491 Ibs sq in 1 PSI 27 7 in water or 2 036 in Mercury ADJUSTMENT Merely turn the knurled knob clockwise to field adjust the operate range from 05 to 12 0 W C MOUNTING DIMENSIONS AIR SWITCH MOUNTING BRACKET wen 1 4 DIA HOLE FOR TUBING 1 15 16 a 3 16 DIA 2 HOLES
3. an by sampling draft or air flow Shuts off firing equipment on fan failure LEGEND N Negative Pressure P Positive Pressure D Pressure Differential po Pressure Sample Line DUCT STRIP HEATERS Switch proves air movement across heaters by positive pressure in front of heater Turns off heater to pre vent burn out on insufficient air flow SPECIFICATIONS ELECTRICAL RATING FIELD ADJUSTABLE OPERATING TEMPERATURE RANGE 15 AMP 125 250 277 VAC N I On pressure rise at 05 40 to 180 F 1 4 HP 125 VAC to 12 w c 1 2 HP 250 VAC SAMPLE LINE CONNECTORS CONDUIT OPENING Male externally threaded 7 16 24 ELECTRICAL SWITCH 7 8 diameter opening UNS 2 A thread complete with nut Single pole double accepts 1 2 conduit and self aligning ferrule throw snap action switch RECOMMENDED OPERATING POSITION SAMPLE LINE CONNECTIONS CONTROL SET POINT Diaphragm vertical Connectors will accept 1 4 O D Adjustable rigid or semi rigid tubing Slip on tubing adaptors optional WH wWHite RODGERS DIVISION PART No 37 4898A EMERSON ELECTRIC CO Printed in U S A Replaces 37 4395 9797 REAVIS ROAD 9110 B ST Louis MissouR 63123 EMERSON 4324 Rev B MOUNTING INSTRUCTIONS oa The Air Switch must be mounted to a vertical surface as shown in above draw ings to assure that diaphragm will be in a vertical plane SEE BACK PAGE FOR MOUNTING DIMENSIONS WIRING All wiring should be done acc
4. ording to local and national electrical codes and ordinances Fig 1 SPDT Switch of Type 770 1 The SPDT switch can be actuated by a positive or negative pressure or bya differential of pressure This control is ideally suited for residential applica tions such as Electronic Air Cleaners and Humidifiers but it is equally well suited for commercial installations including applications where alarm circuits are required Without pressure applied to diaphragm switch contacts are in position shown Fig 2 Typical Air Cleaner Installation Fig 3 Typical Humidifer Installation GROUNDING WIRE AIR SWITCH TYPE 2268 32 NEUTRAL HUMIDIFIER CONTROL HOT ELECTRONIC AIR CLEANER HUMIDIFIER AIR SWITCH SAMPLE LINE CONNECTIONS Male externally threaded with nut and self aligning ferrule POSITIVE PRESSURE ONLY Connect sample line to E F remains open to atmosphere NEGATIVE PRESSURE ONLY Connect sample line to F E remains open to atmosphere POSITIVE ONLY NEGATIVE ONLY LOWER NEGATIVE HIGHER NEGATIVE TWO NEGATIVE SAMPLES HIGHER POSITIVE LOWER POSITIVE Connect highest negative sample to F lower sample to E TWO POSITIVE SAMPLES Connect highest positive sample to E lower sample to F ONE POSITIVE AND ONE NEGATIVE Connect positive sample to E connect nega tive sample to F SEE NEXT PAGE FOR LOCATION OF SAMPLE LINES FAN OPERATION OR TRUE AIRFLOW WITH LITTLE OR NO STA
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