MODEL MW200 MODEL MW600 AIR DRYER

Transcription

1 OPERATING MANUAL MODEL MW200 MODEL MW600 AIR DRYER Mail Address: 226A Commerce St. Tel: Broomfield, CO Fax:

2 TABLE OF CONTENTS 1.0 GENERAL SPECIFICATIONS INSTALLATION AND START-UP PROCEDURES PRINCIPLES OF OPERATION COMPONENT DESCRIPTION...5 Figure 1 - Air Flow Diagram CABINET AIR COMPRESSOR VENTILATING FAN FILTERS HEATLESS AIR DRYER & CAPACITY CONTROL VALVE SWITCH & UNLOADER OUTLET REGULATOR and GAUGE LOW OUTLET ALARM (BASIC UNIT ONLY) ELECTRICAL SYSTEM MAINTENANCE SIX MONTH MAINTENANCE AND INSPECTION ANNUAL MAINTENANCE AND INSPECTION AIR COMPRESSOR CUP SEAL REPLACEMENT REPLACEMENT OF THE INTAKE MUFFLER FILTER ELEMENT...7 Figure 2 Wiring Diagram for Standard Unit...8 Figure 3 Wiring Diagram with "H" Option...9 Figure 4 Wiring Diagram for "D" Option...10 Figure 5 - Parts Index...11 Figure 5 - Parts Index (cont d) MODEL NUMBER CODING OPTIONAL EQUIPMENT HUMIDITY PROTECTION PACKAGE LP LOW HUMIDITY PROTECTION PACKAGE LOW/LOW REGULATOR DISCREET ALARM BOARD LOW RELIEF VALVE LOW-LOW PRESURE ALARM FOR BASIC UNIT HOUR METER

3 1.0 GENERAL 1.1 This manual covers the specifications, installation, start-up, operation, component description, parts list, air flow schematic, wiring diagram and maintenance procedures for the model MW200 and MW600 air dryer. This unit was designed to provide a continuous dry air flow at adjustable pressures of 0-15 PSIG for continuous feed pressure cables, pipe systems, microwave and other systems requiring dry air. Optional low pressure adjustment range is 0.5 to 2.7 PSIG. 1.2 The air dryer carries a One Year Warranty against defective workmanship and materials starting from the date of shipment. Only parts are covered, labor to replace defective parts is not covered by this warranty. All units are tested and inspected before shipment. Any damages incurred in transit should be reported to the carrier immediately upon receipt. The manufacturer is not responsible for damage caused during shipment. 2.0 SPECIFICATIONS PART NUMBER MW200 MW600 NORMAL OUTPUT CAPACITY 200 SCFD 600 SCFD EMERGENCY OUTPUT CAPACITY 350 SCFD 750 SCFD COMPRESSOR MOTOR 1/3 HP 1/3 HP DELIVERED AIR HUMIDITY DEWPOINT Under 2% at 70 F (21 C) -40 F (-40 C) DELIVERED AIR Standard: Adjustable, 0-15 PSIG Optional: Adjustable, PSIG ALARMS Standard: Low Outlet Pressure Optional: High Outlet Pressure High Humidity and Open Circuit Excess Compressor Run Time Power Failure POWER REQUIREMENTS Standard: 115 Volts, Single Phase, 50/60 Hz Optional: 230 Volts, Single Phase, 50/60 Hz. OPERATING TEMPERATURES Minimum: 33 F (1 C) Maximum: 120 F (49 C) WEIGHT 72 LBS 72 LBS DIMENSIONS Width: 24" Depth: 16.25" Height: 15" 3

4 3.0 INSTALLATION AND START-UP PROCEDURES 3.1 Use the handles on the air dryer to lift and move it. Rubber feet are provided for floor mounting. The unit should be located in a well ventilated area which will allow for suitable air circulation through the cabinet. 3.2 The air dryer is designed to operate from a 115 volt, single phase, 60 Hertz power supply (alternative power options are also available). Connect the power cord supplied with the unit to a suitable power supply with a 15 Amp fuse. (If unit is 230 VAC, you will need to supply plug to power cord) 3.3 Remove the plastic plug from the low pressure outlet and the drain outlet located on the lower left side of the unit. Connect the air outlet to the application using 1/4" OD tubing and the 1/4 NPT x 1/4" push-in elbow supplied. There is a second 1/4 NPT X 3/8" push-in elbow supplied which can be used in the drain outlet to drain away condensed moisture discharge. 3.4 Move the On/Off Circuit breaker switch to the "ON" Position. When power is supplied to the unit, the system will build pressure and should begin to supply dry air to the air outlet port. 3.5 The outlet pressure can be adjusted using the outlet pressure regulator located on the front door. Pull the knob on the regulator straight out to un-lock it. Turn the knob counterclockwise to decrease and clockwise to increase the outlet air pressure. Push in on the knob to lock it The moisture indicator on the front door will give an color-change indication of the humidity level in the outlet air. (blue is dry air, pink is moist air). 3.7 Once installation is complete and the start-up procedure has been performed, test for leaks at all external air connections. Operate the unit for 24 hours and repeat the start-up procedure. 4.0 PRINCIPLES OF OPERATION 4.1 An air flow diagram of the air dryer is shown in figure 1. The basic system supplying the dry outlet air includes an air compressor, a precooler, a heatless air dryer, air storage tank and outlet regulator. 4.2 Ambient air is drawn in through the intake filter into the air compressor where it is compressed to 68 PSIG. The hot, moist air then flows first through a pulsation eliminator and second into the aftercooler, to reduce the air temperature and then into the pre-filter where liquid moisture is removed and discharged to the drain outlet. 4.3 The liquid-free air then enters the desiccant air dryer where most of the remaining water in vapor form is removed. The dry air flows into the air storage tank that is monitored by the pressure switch which turns on and off the air compressor to maintain pressure between 20 and 40 PSIG in the tank. Air moves from the tank to the outlet pressure regulator and to the air outlet located on the left side of the cabinet. 4

5 5.0 COMPONENT DESCRIPTION Figure 1 - Air Flow Diagram SAFETY RELIEF VALVE PULSATION ELIMINATOR FAN-COOLED AFTERCOOLER 0.01 MICRON COALESCING FILTER WITH PULSE DRAIN HEATLESS DESICCANT AIR DRYER CAPACITY CONTROL VALVE & GAUGE AIR COMPRESSOR DRAIN OUTLET LOW FLOW BLEED VALVE ASSY OUTLET RELIEF VALVE VENTS TO CABINET OUTLET GAUGE CIRCUIT BOARD SENSOR BYPASS RESTRICTOR ORIFICE SYSTEM GAUGE HUMIDITY BYPASS SOLENOID VALVE HUMIDITY SENSOR / HOUSING UNLOADER SOLENOID VALVE SWITCH AFTER-FILTER MANIFOLD BLOCK OUTLET REGULATOR AIR STORAGE TANK AIR OUTLET MOISTURE INDICATOR 5.1 CABINET The cabinet of the air dryer is ventilated to pull air in over the aftercooler and air compressor and out the side of the cabinet The cabinet cover can be removed for servicing the unit by removing the 8-32 machine screws. 5.2 AIR COMPRESSOR The air compressor is a single cylinder, single stage, rocking piston type. The motor is equipped with built-in thermal overload protection. If the overload shuts down the compressor due to a thermal overload, the motor will automatically reset after cooling down An air intake filter assembly is mounted in the inlet of the cylinder head. The filter assembly has a replaceable filter element which should be replaced at least every six months. See section A safety relief valve is installed in the air compressor head to prevent the pressure in the compressor from building to more than 125 PSIG The air compressor is mounted to a vibration plate which isolates the vibration of the compressor from the cabinet and allows for easy removal of the compressor for service. 5

6 5.3 VENTILATING FAN The ventilating fan is mounted on right side of the cabinet directly above the air compressor head. Air is drawn through the side of the cabinet up over the air compressor and after cooler and exhausted out the left side of the cabinet. Remove the cover panel for access to the ventilating fan The fan thermostat operates the fan whenever the temperature inside the cabinet exceeds 100 F, and shuts off when the temperature drops below 82 F. 5.4 FILTERS The pre-filter, located before the desiccant dryer, removes the liquid moisture condensed by the cooling of the air in the after cooler and discharge the moisture out the drain outlet The after-filter, located before the dry air outlet port, removes any particulates created by the operation of the desiccant dryer. 5.5 HEATLESS AIR DRYER & CAPACITY CONTROL VALVE The heatless air dryer removes virtually all moisture from the supply air through the use of desiccant and pressurization. The capacity control valve is used to maintain a constant back pressure of 68 psig in the heatless air dryer. It also prevents more than the maximum emergency flow rate from flowing through the outlets and serves as a check valve to prevent dry air from the air storage tank from flowing back through the heatless dryer when the compressor shuts down The pressure in the heatless air dryer is critical to the drying process. It must be maintained at 68 PSIG (+/- 2 PSIG) as read on the capacity control valve gauge whenever the air compressor is operating. To adjust the capacity control valve, allow the system pressure to drop to 20 PSIG and the air compressor to start. Pull the lock-ring out away from the valve body and turn the adjustment knob either clockwise to raise the pressure or counterclockwise to lower the pressure. Once the adjustment has been made, push the lock-ring back towards the valve body. 5.6 SWITCH & UNLOADER The pressure switch maintains the system pressure in the air storage tank by turning on the air compressor and desiccant dryer when the system pressure falls below 20 psig and turns them off when the system pressure reaches 40 psig The unloader solenoid valve, located at the heatless dryer inlet port, dumps any pressure in the compressor lines whenever the compressor turns off. This eliminates the air compressor from having to start up against any pressure. 5.7 OUTLET REGULATOR and GAUGE The outlet pressure regulator and outlet pressure gauge are mounted on the front panel. The regulator reduces the pressure of the air to the desired outlet pressure. Pull the knob straight out to un-lock and then turn the knob counterclockwise to decrease and clockwise to increase the outlet air pressure. Push the knob in to lock the setting. 5.8 LOW FLOW BLEED VALVE The low flow bleed valve is designed to bleed a small amount of dry air, putting a minimum load on the system. The valve should be opened only if there is an extremely small amount of usage at the application, or if the output of the system is dead-headed. 6

7 5.9 LOW OUTLET ALARM (BASIC UNIT ONLY) The pressure at the outlet of the outlet pressure regulator is monitored by the low outlet pressure alarm circuit. The low pressure alarm switch is mounted on the inside of the front panel board. If the pressure falls below the factory setting of 6 psig then the front panel alarm lamp will be energized and the alarm contacts will be energized Low outlet pressure alarm switch adjustment: Using the outlet pressure regulator, lower the outlet pressure to the desired alarm pressure point. Remove the cover from the alarm switch and use a 1/4" wrench to slowly turn the adjustment screw in towards the diaphragm body to lower the alarm pressure or out away from the body to raise the alarm pressure. Raise the outlet pressure to clear the alarm and then slowly lower it to check the set pressure. Re-adjust if necessary ELECTRICAL SYSTEM The air dryer is designed to operate from a 230 volt, single phase, 60 Hertz external power source. The on/off switch located on the lower left side of the cabinet must be in the On position. The circuit breaker in the switch is rated for 10 amps. Refer to Section 7, for a detailed electrical circuit diagram for the air dryer. 6.0 MAINTENANCE To extend the life of the air dryer and assure continued satisfactory operation, it is recommended that the following inspection and maintenance procedures be performed at the scheduled intervals. 6.1 SIX MONTH MAINTENANCE AND INSPECTION Perform the following every six months or at 2200 hour intervals. Replace the air compressor intake filter element. (section 6.4) Check the air compressor vibration mounts. Check the operation of the ventilating fan. Check the system pressure switch setting. (section 5.5) 6.2 ANNUAL MAINTENANCE AND INSPECTION Perform the following once every year or at 8000 hour intervals: Perform the six month maintenance and inspection procedures. (Section 6.1) Replace the inlet filter element, P/N PS446. Replace the afterfilter, P/N Install an air compressor cup seal kit. (section 6.3) 6.3 AIR COMPRESSOR CUP SEAL REPLACEMENT Before performing any repairs or maintenance on the air dryer make sure that the start-stop switch is off and disconnect the external power supply to the unit. Refer to the instructions provided with the Cup Seal Replacement Kit, P/N 9800 and perform the procedure to replace the cylinder, cylinder gasket, o-ring and cup seals provided in the kit. 6.4 REPLACEMENT OF THE INTAKE MUFFLER FILTER ELEMENT Remove the intake Muffler cover (outer half) by turning counterclockwise Remove the spent filter element and replace with a new one Install the Intake Muffler cover by turning clockwise. 7

8 Figure 2 Wiring Diagram for Standard Unit 13 HOUR METER A1 24 Gn INCOMING POWER FAN MOTOR L1 L2 G 7 W Bk Gn L1 L2 T1 T2 START-STOP SWITCH FAN THERMOSTAT L1 L2 14 A2 T1 T2 POWER CONTACTOR UNLOADER VALVE 5 6 Gn 3 4 HEATLESS DRYER TIMER AIR COMPRESSOR HEATLESS DRYER 4-WAY VALVE 8 AMBER POWER-ON LIGHT SYSTEM SWITCH RED ALARM LIGHT LOW OUTLET ALARM SWITCH (CLOSED ON ALARM) 10 NO NC L1 L2 T1 T WIRING DIAGRAM MW200 MW600 STANDARD UNIT LOW OUTLET ALARM RELAY SUMMARY ALARM PLUG 8

9 Figure 3 Wiring Diagram with "H" Option SUMMARY ALARM PLUG 13 FAN MOTOR 7 INCOMING POWER Gn L1 L2 T1 T2 START-STOP SWITCH L1 L2 C1 C2 T1 T2 14 POWER CONTACTOR 5 6 Gn Gn 8 AMBER POWER-ON LIGHT 3 4 AIR COMPRESSOR HUMIDITY BY-PASS VALVE TB-1 TB-2 TB-3 TB-4 CONTROL BOARD POWER CYCLE KIT BY-PASS VALVE CONTACTOR RESET BUTTON ALARM TB-5 TB-6 SYSTEM SWITCH FRONT PANEL DISPLAY HOUR METER 28 L1 L2 G 25 W Bk FAN THERMOSTAT UNLOADER VALVE 27 HEATLESS DRYER TIMER HEATLESS DRYER 4-WAY VALVE RIBBON CABLE 7449 TO OPTIONAL DISCRETE ALARM BOARD (SHEET 2) REMOTE ALARMS LD1 LD2 LD10 LD3 LD11 LD4 LD12 LD5 LD6 LD7 LD8 LD9 26 TANK SENSOR LOW LD14 SET LD13 HIGH SET WIRING DIAGRAM MW200 MW600 WITH HUMIDITY PROTECTION PACKAGE TB-7 TB-8 15 RESET SWITCH LINE LOAD HUMIDITY SENSOR

10 Figure 4 Wiring Diagram for "D" Option BLUE BROWN GREEN ORANGE WHITE BLACK RED FLEX CABLE COMMON HIGH PRES LOW PRES HUM RUN EXCS SHUT DOWN PWR FAIL BLK 22 BLK 22 BLK 22 BLK 22 BLK 22 BLK 22 BLK 22 OPTIONAL DISCRETE ALARM BOARD 9521 TERM BD 1 N.O. 2 COM 3 N.C. CLOSE ON ALARM OPEN ON ALARM N.O. CLOSE ON ALARM COM N.C. OPEN ON ALARM N.O. COM N.C. CLOSE ON ALARM OPEN ON ALARM N.O. COM N.C. CLOSE ON ALARM OPEN ON ALARM N.O. COM N.C. CLOSE ON ALARM OPEN ON ALARM N.O. COM N.C. CLOSE ON ALARM OPEN ON ALARM N.O. COM N.C. CLOSE ON ALARM OPEN ON ALARM RIBBON CABLE 7449 TO CONTROL BOARD (SHT 1) 10

11 Figure 5 - Parts Index REF NO. DESCRIPTION Model MW200 OR MW600 1 SYSTEM GAUGE (0 to 100 PSIG) OUTLET GAUGE (0 to 30 PSIG) 7386 OPTIONAL 0 TO 5 PSIG GAUGE POWER "ON" LAMP (115V) 7967 (220V) 4 OUTLET REGULATOR 9628 OPTIONAL LOW/LOW REGULATOR MOISTURE INDICATOR ALARM RESET SWITCH HANDLE ALARM RECEPTACLE , PLUG AIR OUTLET DRAIN OUTLET "ON/OFF" POWER CIRCUIT BREAKER Not Shown HOUR METER (9545 OPTION) (115V), CALL FACTORY FOR 230V 11

12 Figure 5 - Parts Index (cont d) Back View REF NO. DESCRIPTION Model MW200 OR MW PULSATION ELIMINATOR VENTILATING FAN & FAN GUARD FAN 9522 (115V) 9528 (220V) Not Shown FAN GUARD AFTERCOOLER PREFILTER M03-02-D00 ELEMENT PS CONTROL BOARD (FOR 9502) L (115V) L (220V) CONTROL BOARD (FOR 9502-LP) LPSL (115V) LPSL (220V) 17 CAPACITY CONTROL VALVE CAPACITY CONTROL VALVE GAUGE COMPRESSOR AIR INTAKE FILTER 7614 ELEMENT AFTER-FILTER SAFETY RELIEF VALVE AIR STORAGE TANK DESICCANT AIR DRYER MDH3-AHE-S33 (115V) MDH3-DHE-S33 (220V) 23 AIR COMPRESSOR & AIR HOSE 9531 (115V) 9536 (220V) HOSE SWITCH LOW RELIEF VALVE HUMIDITY BY PASS VALVE 7509 (115V) 7515 (220V) 27 COMPRESSOR VIBRATION MOUNTS CABINET VIBRATION MOUNTS UNLOADER VALVE 9626 (115V) 9629 (220V) 30 LOW FLOW BLEED VALVE ASSY 8296 Not Shown POWER CONTACTOR (115V) 7475 (220V) Not Shown LOW ALARM SWITCH (STANDARD UNIT) 8140 (1.5 TO 15 PSIG), 9542 (0.5 TO 5 PSIG) Not Shown LOW ALARM RELAY (STANDARD UNIT (115V) 8426 (230V) 12

13 MODEL NUMBER CODING MW Dryer Model Voltage BLANK= 115/1/50/60 2 = 230/1/50/60 Options H = HUMIDITY PROTECTION PACKAGE (9502) H = HUMIDITY PROTECTION PACKAGE, LOW (9502-LP) (MUST ORDER 9540 WITH THIS OPTION) L = LOW/LOW REGULATOR, 0.5 TO 2.7 PSIG (9540) D = DISCRETE ALARM BOARD (9521) V = LOW RELIEF VALVE (9533) L = LOW/LOW ALARM, 0.1 TO 2.8 PSIG, FOR BASIC UNIT (9547) M = HOUR METER (9545) W = FED STANDARD PAINT SPEC (9598) 8.0 OPTIONAL EQUIPMENT The following optional equipment may be ordered and installed at the factory for this air dryer: HUMIDITY PROTECTION PACKAGE The humidity protection package adds a control board to the dryer which controls the dryer operation and provides the following features: Humidity Alarm Open Circuit Alarm High and Low Pressure Alarms Excess Compressor Run Time Alarm Power Failure Alarm CONTROL BOARD The control board manages the dryer alarms and has the capability to interface with the Pentras automatic cycle panel if more than one dryer is desired to operate on a system and these dryers are to be alternated. The control board holds all alarms for two minutes during initial power up of the air dryer to allow all systems to come up to operating conditions. The control board diagnostic LED s are identified as follows: LD1---- Common Alarm Energized with any alarm LD2---- High Pressure Alarm Energized one minute after condition occurs LD3---- Low Pressure Alarm Energized one minute after condition occurs LD4 --- Humidity Alarm or Open Circuit Energized one minute after condition occurs LD5---- Excess Run Time Alarm Energized approximately 12 minutes after continuous run LD6---- Auxiliary Alarm Not used on this dryer LD7---- Shut Down Alarm Energized after 30 minutes of continuous humidity alarm LD8---- By-Pass Valve Energized immediately when by-pass valve is by-passing LD9---- Compressor Running Energized when the air compressor is running LD10 -- Open Circuit Condition Energized immediately when condition occurs -no delay LD11 -- Humidity Condition Energized immediately when condition occurs -no delay LD12 -- Stand By Mode Used with cycle kit when dryer is alternated with another LD13 -- High Pressure Condition Energized immediately when condition occurs -no delay LD14 -- Low Pressure Condition Energized immediately when condition occurs -no delay The alarm reset switch is located on the front panel and can be pushed to clear and reset all alarms. 13

14 8.1.2 HUMIDITY ALARM The humidity alarm system prevents wet air from being delivered to the dry air outlet of the air dryer. It diverts the wet air out of the system and provides both a visual alarm indication and a dry alarm contact closure when an alarm condition exists. Air passing through the humidity tube is monitored by the humidity sensing element in the humidity sensing tube. The sensing element is connected electrically to the sensor terminals of the control board. If this sensor circuit becomes disconnected the open circuit alarm will be activated. The humidity bypass solenoid is connected to the control board. Under normal operating conditions, the solenoid valve is energized, allowing dry air to flow on through to the air outlet. If the air from the heatless air dryer exceeds an acceptable level of moisture, the sensing element sends a signal to the control board. At this point, the board de-energizes the humidity bypass solenoid valve (green diagnostic lamp LD8 will light on the control board). When de-energized, the solenoid valve diverts the wet air from the system into the atmosphere. At the same time the control board will energize the yellow humidity alarm condition lamp ( LD11) on the control board. If the humidity condition remains after one minute the red humidity alarm lamp will be activated and the external humidity alarm pair will be activated. If after 30 minutes the humidity level does not return to normal than the air dryer will automatically shut itself down and the humidity shut-down lamp will be energized. To clear the humidity alarm the reset switch located on the front panel must be pushed. If exposed to high humidity conditions for an extended length of time the sensing element can fail. Therefore, after the cause of high humidity condition has been repaired, the sensing element may need to be replaced. It is also recommended that the humidity alarm system be tested whenever routine maintenance is performed. The humidity system is also equipped with an open circuit alarm in the event the humidity sensor cable is left unplugged. If the cable is unplugged the yellow diagnostic lamp (LD10) will energize and after a one minute delay the red humidity alarm lamp will energize and the alarm pair will be activated OUTLET ALARMS The pressure at air outlet is monitored by the outlet pressure alarm circuit. The high and low pressure alarm switches are mounted on the control board. They are connected pneumatically via a pressure sensor to the air outlet. The alarm switches are factory set to provide an alarm when the outlet pressure drops to 6 PSIG or rises to 12 PSIG but can easily be reset to preferred alarm pressures. (Customers desiring lower set points should order the 9502-LP package which allows the low set point to be set in the range of 0.1 to 3.1 psig). Low outlet pressure alarm switch adjustment: Using the outlet pressure regulator, lower the outlet pressure to the desired alarm pressure point. With a screw driver turn the dial on switch R2 slowly counterclockwise to reduce the setting and clockwise to increase the setting. When the yellow diagnostic "Low Set" LED light comes on the point is set. After a one minute delay the red low pressure alarm lamp will energize and the alarm pair will be activated. To reset the alarm push the reset switch located on the right side of the electrical box. 14

15 High outlet pressure alarm switch adjustment: Using the outlet pressure regulator, raise the outlet pressure to the desired alarm pressure point. With a screw driver turn the dial on switch R1 slowly counterclockwise to reduce the setting and clockwise to increase the setting. When the yellow diagnostic "High Set" LED light comes on the point is set. After a one minute delay the red high pressure alarm lamp located on control board will energize and the alarm pair will be activated. To reset the alarm push the reset switch located on the right side of the electrical box EXCESS COMPRESSOR RUN TIME ALARM CIRCUIT The excess compressor run time alarm circuit provides an alarm signal in the event the air compressor pressure switch remains closed for more than 12 minutes. An excess run time alarm could be an indication of an air leak in the pressure system or deterioration in the performance of the air compressor. Once a run time alarm is brought in, it "locks in", and must be manually cleared using the reset switch located on the right side of the electrical box. When the air compressor pressure switch closes, a 12 minute timing cycle begins on the control board. If the pressure switch opens before 12 minutes, the timing cycle ends. If the pressure switch remains closed for the complete timing cycle, the delay relay energizes the excess run time LED (LD5) on the control board and the alarm pair will be activated. Once energized, the alarm must be manually reset by pressing the reset switch located on the right side of the electrical box LP LOW HUMIDITY PROTECTION PACKAGE Uses a control board with lower pressure alarm settings for use with the Low/Low pressure regulator P/N Ranges are 0.1 to 3.1psig for the low pressure alarm setting and 3.2 to 6.5 psig for the high pressure alarm setting. Otherwise, the features are the same and it functions the same as the P/N LOW/LOW REGULATOR Changes the standard range 0 to 15 psig outlet regulator to a low range 0.5 to 2.7 psig outlet regulator and also switches the standard outlet pressure gauge from the standard 0 to 30 psig range to a 0 to 5 psig range. To adjust the Low/Low pressure regulator remove the black cover and using a wide blade screw driver turn clockwise to raise the pressure and counter-clockwise to decrease the pressure DISCRETE ALARM BOARD For use with the 9502 or 9502-LP Humidity Packages control board. Plugs into the control board and breaks out the individual alarm types for discreet alarm reporting. Alarms can be wired for normally open or normally closed operation LOW RELIEF VALVE This valve is installed just before the air outlet to prevent over pressure from being supplied to the outlet. Factory setting is 2.5 PSIG. To adjust, loosen locknut and turn slotted screw in clockwise direction to increase the pressure relief setting and counter-clockwise to decrease the pressure relief setting LOW-LOW PRESURE ALARM FOR BASIC UNIT For basic units only, adds the low pressure alarm range setting of 0.1 to 2.80 psig when using the P/N 9540 LOW/LOW Pressure without the humidity package control board HOUR METER Adds an hour meter which keeps a running total of the air compressor "on" time. This is useful to help determine when the air compressor is in need of maintenance. 15