Macurco ND1-FCK User Manual

MACURCO GAS DETECTORS

ND1-FCK

FIELD CALIBRATION KIT

CONTENTS OF THE KIT:

1. Gas Cylinder of 5ppm nitrogen dioxide.

2. Gas regulator with white cap fitting.

3. These instructions.

GENERAL INFORMATION:

The heart of the ND-1 is a microcomputer. It constantly monitors various internal operating
parameters, the ambient temperature, and the Nitrogen Dioxide (NO2) reading. The NO2 reading is
determined by measuring the voltage across an electro-chemical cell whose chemistry responds to
NO2. The microcomputer takes the NO2 data, compensates it for temperature, and then compares
this data to the alarm set point.

All ND-1 NO2 Detectors are factory calibrated when they are shipped to the customer. This
calibration should be within specifications for 6 months to a year. Some jurisdictions, local
standards, or customer preferences require periodic recalibrations. This Kit provides the means to
fit those requirements. Macurco recommends checking the operation of the ND-1 every six months,
either through use of the procedures given in the operating instructions or this Field Calibration Kit.

WHERE TO DO THE CALIBRATION?

The ND-1 will need to be partially disassembled for this procedure. It will be easiest to do this on a
bench in a work area. However, if two people are available, it can be done at the actual working
location of the ND-1.

FIELD CALIBRATION PROCEDURE:

NOTE: The ND-1 must have been power continuously for a minimum of 72 hours before

proceeding.

1. Open the access door of the ND-1 case.

2. Remove the two bottom screws that secure the interior faceplate, and swing the faceplate up.

3. Ensure that the digital display is "ON" before starting.

4. Turn both the "FAN" and "ALARM" adjustments fully clockwise before proceeding.

5. Connect a multi-meter across R27 (directly left of the large chip), with the positive lead
connected to the lead-end with the loop.

6. Adjust RA5 "ZERO" potentiometer (multi-turn type) until the voltmeter reading is 0.00 +/- 0.10
VDC.

7. Wait for the multi-meter display to stabilize. Repeat steps 6 and 7 until the meter reading
remains stable.

8. Assemble the gas cylinder to the regulator and the rest of the tubing. Turn-on the NO
and ensure that the tank pressure is sufficient to complete the calibration.

9. Place the white applicator attached to the regulator hose over the electrochemical cell, applying
NO2 to the sensor.

10. Wait for the meter reading and the display to respond - this may take several minutes.

11. Wait 30 minutes, and then adjust the RA4 "GAIN" potentiometer (multi-turn-type).

Rev: 08/01

regulator,

2

12. Note the gas mixture value in parts-per-million that is located on the label of the gas cylinder.

Adjust the potentiometer (RA4) until the display reading matches the gas mixture being used to
calibrate the unit.

13. Remove the NO2 gas from the sensor, and remove the gas regulator from the cylinder.

14. Wait at least 1 hour on the first adjustment cycle. On subsequent adjustment cycles, this delay

may be shortened to 15 minutes.

15. Repeat steps 6 through 14 until the "ZERO" adjustment maintains 0.00 +/- 0.10 Vdc, and the

"GAIN" adjustment reflects the contents of the gas cylinder +/- 0.1 ppm of NO

.

2

16. If a problem occurs while performing this procedure, contact the factory.

17. Set the "FAN" and "ALARM" adjustments to the desired activation levels.

18. Swing the interior faceplate down, and secure it with the screws removed in step 2. Close the

exterior door.

GAS TEST

1. Open the front gray cover of the ND-1

2. Remove the two Philips screws located at he bottom of the gold face plate. The face plate

should now hinge up to expose the ND-1 printed circuit board

3. Open the FCK. Connect the gas cylinder to the regulator

4. Check the pressure gauge on the regulator. If you have 25 psi or less you will need to replace

the gas canister

5. Place the cap from the regulator over the sensor

6. Wait 5 minutes with the gas applied continuously. The ND-1 takes samples every 2 1/2 minutes

7. After the five minutes the digital display should read 5 ±10%, plus the accuracy of the gas

(normally ±2%)

8. Once the reading has been taken remove the gas from the sensor. Note: If the display did not
read within the given parameters, there are three possibilities:

a. the gas cylinder is empty, check the pressure gauge. Replace the gas cylinder if 25

psi or less

b. the unit needs to be re-calibrated (go through recalibration and re-test)
c. the detector is in need of servicing (return unit to factory for servicing)

9. Wait 7 1/2 minutes for the ND-1 to stabilize, with no gas applied to the sensor. You might test
another unit at 5 ppm while waiting. If you do not test another unit with the 5 ppm gas
disconnect the canister from the regulator

10. When testing is complete disassemble the regulator and cylinder. Note: The specification for
repeatability (±10%) is after calibration at 5 ppm. The gas accuracy (normally ± 2%) needs to
be considered also.

NOTE: Two to three ND-1s may be calibrated with one FCK. The only limitation is the amount

of gas contained in the cylinder. Replacement cylinders are available.

RETURN INSTRUCTIONS:
The calibration kit should be carefully packed (well padded) and returned to:

Macurco

3946 South Mariposa Street

Englewood, Colorado 80110

Please include a note advising the nature of the problem.

Rev: 08/01