HIGH RANGE DIGITAL DEW POINT METER & MONITOR Model #8074 IMS #116075 (TED1-8074) 2004 IMS Co. October, 2004 IMS Company 10373 Stafford Road Chagrin Falls, OH 44023-5296 Telephone: (440) 543-1615 Fax: (440) 543-1069 Email: sales@imscompany.com Website: imscompany.com
TABLE OF CONTENTS Safety Summary... 2 Product Description... 3 Product Specifications... 4 Operation... 5 Installation... 6 Choosing A Sampling Location... 6 Normal Sampling... 6 Positive Pressure Sampling... 6 Test Results... 7 Maintenance... 8 Sensor Replacement Procedure... 8 Alarm Set Point Adjustment... 8 Recorder Output Selection... 9 Display Units Selection... 9 Electronic Test Procedure... 9 Replacement Parts... 10 ILLUSTRATIONS Parts Identification... 11 Assembly Drawing... 13 Mounting and Wiring Diagram... 14 Airflow Schematic... 15 October, 2004 Page 1 of 16
SAFETY SUMMARY This manual uses the following signal words to call attention to the safety sign and to designate a degree or level of hazard seriousness. 1. DANGER: indicates an imminently hazardous situation which, if not avoided, will result in death or serious injury. This signal word is limited to the most extreme situations. 2. WARNING: indicates a potentially hazardous situation which, if not avoided, could result in death or serious injury. 3. CAUTION: indicates a potentially hazardous situation which, if not avoided, may result in minor or moderate injury. Also used to alert against unsafe practices or property damage only accidents. 4. NOTE: indicates general safe practices, machine use instructions and information, property damage only hazards, temporary hazards, precautions to avoid a hazard, results of not avoiding a hazard, or any combination of these messages. 5. SYMBOL/PICTORIAL: conveys a message without words. 6. SAFETY ALERT SYMBOL: indicates a potential personal injury hazard; an exclamation point inside a triangle. October, 2004 Page 2 of 16
PRODUCT DESCRIPTION The IMS Company Model 8074 Dew Point Meter and Monitor is used in the Plastics Industry to check for moisture in the output air from a hot air dryer, mechanical refrigeration-type dryer, or from the ambient air. The reading is useful as a reference point for the drying and molding process and is given as Dew Point Temperature. The dryer the air, the lower the dew point. You can monitor the performance of your drying equipment by measuring the dew point of drying air. A green light indicates dew points of drying air at or below the set point while a red light and audible alarm indicate dew points above the set point. Dew point temperature is digitally displayed. A cooling coil cools sampled air to a measurable temperature and the unit has a bleed valve for high pressure testing. A chart recorder outlet has a 4 to 20 ma DC linear signal that can be used by a chart recorder to track levels of dryness. The output can easily be changed to 0 to 5 Volts (refer to instructions on Page 8). The unit is self-contained and portable. Model 8074 Dew Point Meter and Monitor is factory calibrated with a NIST traceable certificate. The meter s sampling pump draws an air sample and pumps it into a chamber that contains a moisture sensor called a hygrosensor. The amount of moisture in the sample affects the sensor s electrical resistance. Interpreting that resistance, the meter shows dew point temperature on the LED display. NOTE Although the Model 8074 reads dew points from +10 to +70 F, the chart recorder output is on a -40 to +70 F scale. IMS Chart Recorder #115615 is scaled from -40 to +70 F. If you use another chart recorder, you might want to set it to 50% of scale. DEW POINT TEMPERATURE --- A LAYMAN S EXPLANATION Warm air can hold a lot of moisture. As air temperature drops, so does its ability to hold moisture. At some point the air becomes saturated and dew forms. That point is called the dew point temperature of that air sample. Rather than actually chilling a sample to the point of saturation, the IMS Company Model 8074 Dew Point Meter and Monitor measures the moisture content and calculates the dew point temperature. For example, if this meter reads +40 F, it means that the actual air temperature would have to drop to +40 F before the moisture in the sample would form dew. October, 2004 Page 3 of 16
SPECIFICATIONS Dew Point Range...+10 F to +70 F (-12 C to +21 C)...at +73 F sample air temperature...0 F to +50 F (-18 C to +10 C)...at +50 F sample air temperature...+35 F to +90 F (+2 C to +32 C)...at +100 F sample air temperature Ambient Air Temperature...50 F to +100 F (10 C to 38 C)...sample air temperature is approximately...equal to ambient air temperature Accuracy...+2 F (1 C) Pressure Range...-1 to +7 psig Alarm Indication...Red Light and Audible Alarm With Silencer Switch Alarm Set Point...+50 F (10 C) Adjustable Recorder Output...2-pin connector...4-20ma Scaled as -40 F to +70 F...Jumper Selectable 0 to 5 Volt Sensor Part No....1826-2 Dimensions...8074 Carrying Case 9 X 12-1/2 X 5 Deep Net Weight...8 lbs. Power Requirements...115VAC +10% 50/60Hz 0.1 AMPS...(230V available) Pump Specifications...Flow: 2.5L/min. (0.08 SCFM)...Vacuum: 6 Hg...Pressure: 3.2 psi...(all pump specifications are nominal) October, 2004 Page 4 of 16
OPERATION PRINCIPLE OF OPERATION The Model 8074 Dew Point Meter and Monitor has a vacuum pump that pulls sample air into a sensor manifold. The sensor manifold contains a 3-element moisture sensor and a temperature transducer. With humidity and temperature signals, the circuitry can provide temperature compensated dew point measurement. The Dew Point Meter and Monitor is normally used to sample air that is at a pressure between 1 and +7 psig. Higher pressures can be tolerated by opening the selector valve on the side of the unit (refer to the POSITIVE PRESSURE SAMPLING Section on Page 6). Air up to 500 F (dry bulb) can be sampled if appropriate tubing is used. The plastic Tygon tubing supplied can withstand temperatures up to 180 F. October, 2004 Page 5 of 16
INSTALLATION Refer to Page 11 for Parts Identification. NOTE A key for the meter case and the unit s serial number tag are behind the foam padding in the case lid when the unit is shipped. CHOOSING A SAMPLING LOCATION The best sampling location is usually the main distribution line of the air system. Follow these guidelines when selecting a sampling location: 1. Sample air should be free of oil, particulates, and condensation. 2. Be aware of ambient and sample air temperature limitations listed in the SPECIFICATIONS Section on Page 4. NORMAL SAMPLING Normal sampling implies that the sampled air pressure is between -1 and +7 psig. This condition is typical of plastic hopper drying systems. 1. Turn the selector valve clockwise until fully closed. The valve must be fully closed to prevent ambient air from leaking in. 2. Connect the sample inlet tubing with filter to a convenient sampling location. To check a dryer s performance, sample from the dryer s output hose. To check your process material for dryness, sample from the hopper s return hose. CAUTION Do not bypass the cooling coil or cover it with insulating material. To do so will expose the sensor to elevated temperatures and may cause damage. 3. Turn the power on and allow the reading to stabilize. It may take as much as 5 to 15 minutes for the dew point to drop and 10 to 25 minutes for a reading to stabilize. You can silence the alarm with the switch on the side of the panel. When operation is done, turn power off then disconnect sample tubing. POSITIVE PRESSURE SAMPLING (ABOVE 7 PSIG) Turn selector valve counterclockwise to OPEN position. This will vent air sample after it flows through sensor chamber. Connect sample tube to sampling location. For consistent positive pressure sampling above 7 psig, contact an IMS Customer Service Representative at 1-800-537-5375 about Model 8076. October, 2004 Page 6 of 16
INSTALLATION (continued) TEST RESULTS A green light indicates a properly functioning refrigerant dryer. Very dry air will cause the Dew Point Meter and Monitor to indicate below 10 F. If the unit is sampling process air after it leaves a drying hopper filled with material, initially high dew points may be encountered. As the moisture is purged out of the material, the dew point decreases. When the Dew Point Meter and Monitor displays a High Alarm, the following conditions should be considered: 1. There is a leak in the dryer system or sampling line. 2. The dryer is overloaded by excessively wet material. 3. The dryer has experienced mechanical or electrical failure. 4. The Dew Point Meter and Monitor has failed (see ELECTRONIC TEST PROCEDURE Section on Page 9 and MAINTENANCE Section on Page 8). NOTE The built-in audible alarm can be silenced with the ALARM switch on the side of the panel. October, 2004 Page 7 of 16
MAINTENANCE The Dew Point Meter and Monitor normally does not require calibration, and in most applications, the sensor will provide years of service. However, the easiest and most reliable way to insure consistent accuracy is to replace the sensor annually. DANGER Live Electric Parts could cause DEATH or SHOCK Unplug meter or protect yourself from electric parts when servicing. Only Qualified Technicians are to service this meter. SENSOR REPLACEMENT PROCEDURE 1. Remove front cover and locate black sensor manifold. 2. Loosen hex nut on manifold and slide nut along wires away from manifold. 3. Lift 4-pin insert out of manifold to reveal sensor assembly. 4. Use a blunt object to pry sensor assembly out of 4-pin insert. 5. Observe the pin pattern on the new sensor assembly and match to the 4-pin insert. Use moderate finger pressure to press in the new sensor assembly. The sensor does not need to seat fully into the 4-pin insert. 6. Replace sensor assembly and 4-pin insert into manifold and hand tighten the hex nut. ALARM SET POINT ADJUSTMENT Locate the display function switch (S1) on PC Board. Refer to Mounting and Wiring Diagram on Page 14 for exact location. NOTE: Only one position of this switch should be ON at a time. 1. To view and adjust Relay #1 set point, turn the #1 Position of S1 OFF and the SET1 Position #2 ON. Turn the SET1 of P2 near the switch to the desired set point. 2. When finished adjusting the set point, return S1 to the default operating mode by turning OPER position ON and all others OFF. 3. A small red LED near the potentiometer P2 indicates when an alarm is occurring. October, 2004 Page 8 of 16
MAINTENANCE (continued) RECORDER OUTPUT SELECTION (TB3) For 4 to 20mA connect wires to Terminals 2 and 3 of TB3 of the PC Board. Terminals 1 and 2 are for 0 to 5 Volts. Refer to Mounting and Wiring Diagram on Page 14 for exact location. -40 F = 0 Volts or 4mA +70 F = 5 Volts or 20mA DISPLAY UNITS SELECTION - CHANGE DISPLAY FROM F TO C To change the digital display to C, use needle nose pliers and move jumpers J6 and J7 to the C position on PC Board. Refer to Mounting and Wiring Diagram on Page 14 for exact location. ELECTRONIC TEST PROCEDURE This procedure is only necessary if circuit is thought to be malfunctioning. 1. Locate jumper J5 on the board and move it away from the TC position. This disables temperature compensation. Refer to Mounting and Wiring Diagram on Page 14 for exact location. 2. Disconnect the sensor wires at terminals A and B. Check display for 1 F ± 1 F. 3. Place a jumper across sensor terminals A and B. Check display for 70 F ± 1 F. 4. Remove power and return jumper J5 to the TC position. 5. If these parameters cannot be met, contact an IMS Company Customer Service Representative at 800-537-5375. If the circuit does not function properly, the Dew Point Meter and Monitor should be returned to the factory for repair. Please contact an IMS Company Customer Service Representative at 800-537-5375 for instructions on returning equipment for repair. October, 2004 Page 9 of 16
REPLACEMENT PARTS DESCRIPTION OLD IMS # NEW IMS # Desiccant Tube...TEZZ-6245...103796 Filter...TEZZ-3305005...103808 Hygrosensor...TEZZ-1826-2...116540 October, 2004 Page 10 of 16
PARTS IDENTIFICATION Green Digital Display Red Exhaust At Or Below Above Selector Set Point Set Point Valve Indicator Indicator Alarm Alarm Switch Cooling Tube On/Off Switch Sampling Tube Chart Recorder Output Sample Exhaust Tube October, 2004 Page 11 of 16
PARTS IDENTIFICATION (continued) Sensor Cable Sensor Chamber Sampling Pump October, 2004 Page 12 of 16
ASSEMBLY DRAWING October, 2004 Page 13 of 16
MOUNTING AND WIRING DIAGRAM TB3 Jumper J6 Jumper J7 Jumper J5 Display Function Switch S1 October, 2004 Page 14 of 16
AIRFLOW SCHEMATIC October, 2004 Page 15 of 16
MAINTENANCE RECORDS AND NOTES October, 2004 Page 16 of 16