ENMET Corporation PO Box 979 Ann Arbor, MI 48106-0979 ISA-44RAL-OD ISA-44RAH-OD Operation and Maintenance Manual 80003-010 12-31-91 MCN 204, 02/05/99 MCN 212, 03/29/99 MCN-294, 03/07/03 MCN-304, 10/17/03
Table of Contents 1.0 INTRODUCTION...................................................................................................................................................................................1 1.1 OPERATING PRINCIPLE ......................................................................................................................................................................... 1 1.2 ISA-44RAH-OD.....................................................................................
List of Figures and Tables FIGURE 1 A: S AMPLE HEAD ASSEMBLY, TYPICAL HIGH PRESSURE HO O K-UP ................................................................................ 2 FIGURE 1: CONTROL UNIT FEATURES ....................................................................................................................................................... 5 FIGURE 2: CIRCUIT BOARD WITH TERMINAL BLOCKS ........................................................................................................
ISA-44RAL-OD / ISA-44RAH-OD ENMET Corporation 1.0 Introduction Sandblasting, welding and spray painting are examples of activities that create potentially hazardous environments. Such environments contain toxic gases, dust and fumes. An air compressor system with hoods or masks supplies clean breathing air to workers and minimizes the risk of injury or death; however, carbon monoxide (CO) can contaminate the air in a compressor system.
ENMET Corporation ISA-44RAL-OD / ISA-44RAH-OD 1.2 ISA-44RAH-OD The ISA-44RAH-OD is designed to monitor breathing air from cylinders at pressures up to 5000 psi. The equipment consists of an ISA-44RAL-OD with the addition of a high pressure regulator at the sample air input as shown in Figure 1a. The high pressure regulator must be plugged into the high pressure line with an appropriate fitting; the output is connected to the ISA-44RAH-OD by means of a quick release pneumatic fitting.
ISA-44RAL-OD / ISA-44RAH-OD ENMET Corporation 2.0 Upon Receipt 2.1 Unpack Unpack the ISA-44RAL(RAH)OD and examine it for shipping damage. If such damage is observed, notify both ENMET customer service personnel and the commercial carrier involved immediately. Regarding Damaged Shipments NOTE: It is your responsibility to follow these instructions. If they are not followed, the carrier will not honor any claims for damage.
ENMET Corporation ISA-44RAL-OD / ISA-44RAH-OD 3.0 Features / Definition of Parts 3.1 Electronics Control Unit 3.1.1 Carbon Monoxide Detection Channel Refer to Figure 1 FEATURE DESCRIPTION POWER LIGHT (G REEN) Light on: Channel operating Light off: Alarm condition or power interrupted. ALARM LIGHTS Visual alarms (steady lights). AMBER: unit in low level alarm. RED: unit in high level alarm. AUDIO ALARM Audio alarm: activates when high alarm level is exceeded. METER A CO concentration meter.
ISA-44RAL-OD / ISA-44RAH-OD ENMET Corporation Oxygen Alarm Light (Amber) CO Low Alarm Light (Amber) Oxygen Power Light (Green) CO Alarm High Light (Red) Oxygen Gain Adjustment CO Power Light (Green) CO Meter Oxygen Meter Audio Alarm Operation Switch Cable Figure 1: Control Unit Features 5
ENMET Corporation ISA-44RAL-OD / ISA-44RAH-OD 3.2 Internal Electronic Circuitry Figure 2 shows the circuit board and terminal blocks housed inside the hinged oiltight control unit. Specific relays and adjustments are defined: INTERNAL RELAY CONTACTS: Relays can be used to activate an external remote alarm system when a hazardous CO level is detected. These are double-pole relays (Figure 2 upper right) with terminals "normally open"(N.O.), "normally closed"(N.C.), and "common"(COM.
ISA-44RAL-OD / ISA-44RAH-OD ENMET Corporation 3.2.1 CO Circuit Refer to Figure 2 PURGE ADJUST POTENTIOMETER Adjusts purge voltage. Operation switch must be in purge position to adjust purge voltage. HEATER A DJUST POTENTIOMETER For adjusting the MOS sensor heater operating voltage. DO NOT adjust this potentiometer unless a voltage reading indicates that an adjustment is necessary. (May need adjusting after replacing sensor cable assembly). Voltage: .86 Vdc + .
ENMET Corporation ISA-44RAL-OD / ISA-44RAH-OD 3.3 Sample Head Assembly The sample head connects to a compressed air line. This unit continuously monitors the respiratory lines for carbon monoxide and oxygen. Figure 4 illustrates this unit. Assembly parts are listed and defined below: PRESSURE R EGULATOR: Reduces the pressure of sample air from the compressed air line before passing over the sensor. It includes a meter to measure the pressure in pounds per square inch (psi) at the regulator exit.
ISA-44RAL-OD / ISA-44RAH-OD ENMET Corporation 4.0 Installation After becoming familiar with the main parts and their functions, follow the installation procedure as outlined below: 1. Choose an appropriate location for mounting the electronics control unit. Do not locate the sampling head assemble in an area where quick temperature changes are likely to occur, like near an outside door. The oxygen cell is sensitive to temperature and the circuitry for this cell cannot track rapid changes in temperature.
ENMET Corporation ISA-44RAL-OD / ISA-44RAH-OD 5. Apply 115 Vac and/or 12 Vdc power to the appropriate terminals (refer to Figure 2). As an emergency back-up power source, both ac and dc power can be applied at the same time. Current will flow from the ac source. DC current will flow only when the ac power is interrupted. NOTE: 220 Vac power requires a change in the transformer hook-up. This change is best done at ENMET or an ENMET service center. 6.
ISA-44RAL-OD / ISA-44RAH-OD ENMET Corporation 5.2 Oxygen Detection Channel After installation is completed, the oxygen meter must be adjusted to a clean air reference point of 20.9% oxygen by volume. The equipment necessary for this is included in a calibration kit for ISA-44RAL-OD / RAH-OD units, ENMET part number 03430-001. 1. 2. 3. 4. 5. 6. Turn operation switch to HORN O FF position. Connect the calibration fixture to the bottled clean air (20.
ENMET Corporation ISA-44RAL-OD / ISA-44RAH-OD 5.3.2 Air Quality and Pressure Adjustments For the OXYGEN D ETECTION CHANNEL : Atmospheric conditions and conditions inside your air compressor are constantly changing. In order to maintain a clean oxygen reading of 20.9% oxygen the oxygen Gain Potentiometer must be adjusted periodically. Check the oxygen meter daily. If it continually shows a percentage other than 20.
ISA-44RAL-OD / ISA-44RAH-OD ENMET Corporation 6.0 Calibration 6.1 Carbon Monoxide Detection Channel Calibration The following procedure is for checking the calibration level and for recalibrating the Carbon Monoxide Channel of the ISA-44RAL-OD. Refer to Figure 5 and Figure 2. Perform A Complete Recalibration Periodically (at least monthly) and: • When you replace the sensor. • When the sensor encounters severe conditions (i.e., gross exposure to smoke or liquid hydrocarbon).
ENMET Corporation 6. 7. ISA-44RAL-OD / ISA-44RAH-OD Turn operation switch to HORN O FF. Open the regulator on the top of the high-level calibration gas cylinder. This brings the gas into the sampling assembly. Regulate the flow of calibration gas according to the "...SET" mark or between 7 – 12 PSI on the pressure regulator dial. 8. Let the high-level calibration gas flow into the system for 5 minutes. This assures a full and balanced response from the sensor.
ISA-44RAL-OD / ISA-44RAH-OD ENMET Corporation 6.2 Oxygen Circuit Calibration Refer to Figure 2 This procedure is given in reference to an S-2 cell, which is ENMET P/N 67013-008 as furnished as a replacement cell. MATERIALS § digital voltmeter § small screwdriver PROCEDURE 1. 2. Turn operation switch to HORN O FF position. Null Adjust a. Disconnect the oxygen cell from the circuit by disconnecting leads at TB3-8 (+) (terminal block 3-position 8) and/or TB3-9 (-).
ENMET Corporation ISA-44RAL-OD / ISA-44RAH-OD 7.0 Routine Maintenance Since the ISA-44RAL-OD/RAH-OD is a safety instrument, it requires periodic testing and recalibration. Refer to Operation and Calibration sections of this manual for testing and recalibration procedures. AT REGULAR INTERVALS: 1. Rotate operation switch to PURGE O N. This interval varies with the amount of contaminants present in the air system, but purge for at least 10 minutes.
ISA-44RAL-OD / ISA-44RAH-OD ENMET Corporation 7.3 Oxygen Cell Replacement The oxygen fuel cell has a six-month warranty. The average lifetime of the cell is twelve months. Replace the cell when you can no longer adjust the oxygen gain potentiometer, outside on the front panel, so that the oxygen channel meter reads 21%. An oxygen circuit that is in constant alarm is a good indication that the oxygen fuel cell is either expired or grossly contaminated. See Figure 6 MATERIALS § screwdriver PROCEDURE 1.
ENMET Corporation ISA-44RAL-OD / ISA-44RAH-OD 7.4 Hydrocarbon Filter Replacement The charcoal absorption filter for hydrocarbons will need periodic replacement. The length of time between replacement depends on the instrument usage and VOC (Volatile Organic Compounds) level in the breathing air supply.
ISA-44RAL-OD / ISA-44RAH-OD ENMET Corporation 9.0 Warranty ENMET warrants new instruments to be free from defects in workmanship and material under normal use for a period of one year from date of shipment from ENMET. The warranty covers both parts and labor; however, oxygen cells are limited to a warranty period of six (6) months from date of shipment from ENMET. Equipment believed to be defective should be returned to ENMET within the warranty period (transportation prepaid) for inspection.
ENMET Corporation ISA-44RAL-OD / ISA-44RAH-OD Notes: 20
PO Box 979 680 Fairfield Court Ann Arbor, Michigan 48106-0979 734.761.1270 Fax 734.761.3220 Returning an Instrument for Repair ENMET instruments may be returned to the factory or any one of our Field Service Centers for regular repair service or calibration. The ENMET Repair Department and Field Service Centers also perform warranty service work.
Repair Return Form Mailing Address: ENMET Corporation PO Box 979 Ann Arbor, Michigan 48106 Phone Number: FAX Number: Shipping Address: ENMET Corporation Attn: Repair Department 680 Fairfield Court Ann Arbor, Michigan 48108 734.761.1270 734.761.
