WatchGas NEO User manual
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NEO Photoionization Detectors
Service Manual
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NEO Photoionization Detector Service Manual
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Contents
Contents 2
Read Before Operating 3
1. General Information 4
2. Maintenance 5
2.1. Cleaning or Changing PID Sensor / Lamp 5
2.1.1. Lamp Cleaning and Changing 5
2.1.2. Sensor Cleaning 6
2.1.3 PID Sensor / Lamp Diagnostics 6
2.2. Sampling Pump 7
2.2.1. Pump Service Procedures 7
2.3. Battery Replacement 9
3. Troubleshooting 11
4. Replacement Parts 12
Contact Information 12
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Service Manual Photoionization Detector NEO
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STATIC HAZARD: Clean only with a damp cloth.
For safety reasons, this equipment must be operated and serviced by qualied personnel only. Read
and understand the instruction manual completely before operating or servicing.
• Use only WatchGas battery pack M011-3002-000. Substitution of components may impair intrinsic
safety. Recharge batteries only in non-hazardous locations.
• Do not mix old and new batteries or batteries from dierent manufacturers.
• For maximum safety, the accuracy of the instrument should be checked by exposing it to a known
concentration calibration gas before each day’s use.
• Do not use USB/PC communication in a hazardous location.
Read Before Operating
This manual must be carefully read by all individuals who have or will have the responsibility of using,
maintaining, or servicing this product.
The product will perform as designed only if it is used, maintained, and serviced in accordance with the
manufacturer’s instructions.
The user should understand how to set the correct parameters and interpret the obtained results.
WARNING
To reduce the risk of electric shock, turn the power o before removing the instrument cover. Disconnect
the battery before removing sensor module for service. Never operate the instrument when the cover
is removed. Remove instrument cover and sensor module only in an area known to be non-hazardous.
CAUTION
• When the instrument is taken out of the transport case and turned on for the rst time, there may be
some residual organic or inorganic vapor trapped inside the detector chamber. The initial PID sensor
reading may indicate a few ppm. Enter an area known to be free of any organic vapor and turn on
the instrument. After running for several minutes, the residual vapor in the detector chamber will be
cleared and the reading should return to zero.
• The battery of the instrument discharges slowly even if it is turned o. If the instrument has not been
charged for 5 to 7 days, the battery voltage may be low. Therefore, it is a good practice to always
charge the instrument before using it. It is also recommended to fully charge the instrument for at
least 10 hours before the rst use. Refer to this User Guide’s section on battery charging for more
information on battery charging and replacement.
• Do not remove the lter when the instrument is on, otherwise, dust entry will reduce the accuracy
of measurement, shorten the life of the sensor, and possibly damage the sensor.
SPECIAL NOTES
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1. General Information
The NEO is one of the most advanced handheld VOC (Volatile Organic Compound) monitors availa-
ble for ppb (parts per billion) detection. The NEO oers several models from the most sensitive 1 ppb
to a high range up to 15000 ppm for dierent applications and user selections. Novel designs of the
photo-ionization detector (PID) and ultraviolet (UV) lamp provide outstanding sensitivity, stability and
reproducibility. Options include real time data monitoring with a built-in wireless modem using Watch-
Gas Suite application software.
Key Features
• Size: 9.1 x 2.9 x 2.2 in (230 x 74 x 55 mm)
• Weight: 24.95 oz (708 g)
• 1 ppb to 15000 ppm ranges of VOC
• 3-second response time for 90% change (using isobutylene)
• Large and intuitive display
• Integrated correction factors list of more than 200 compounds
• Built-in pump for up to 30 meters sampling distance
• Man-down alarm with real-time remote wireless notication
• ISM wireless connection option
• Easy service and maintenance
• Micro-USB charge port
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Service Manual Photoionization Detector NEO
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2. Maintenance
2.1 CLEANING OR CHANGING PID SENSOR / LAMP
2.1.1 Lamp Cleaning and Changing
1. Unscrew the Sensor Cap and pull the sensor straight out, using a
slight rocking motion if necessary.
2. Put on nger gloves and pull out the lamp. Insert a new lamp, or
clean the existing lamp as described below.
3. Use a cotton swab wetted with methanol to clean the at window
surface of the lamp. If greasy dirt is hard to remove using methanol,
the window can be polished using ne alumina powder polishing
paste.
4. Use a clean tissue to wipe the lamp window again.
5. Re-insert the cleaned lamp, plug in the sensor and screw on the
sensor cap.
6. Always re-calibrate the PID after cleaning the lamp and/or sensor.
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2.1.2 Sensor Cleaning
1. Unscrew the sensor cap.
2. Pull the sensor straight out, using a slight rocking motion if
necessary.
3. Put the sensor into a beaker and cover it with pure methanol or
ethanol.
4. Put the beaker into an ultrasonic cleaning bath and sonicate for
5 minutes. Then replace the alcohol with distilled water and soni-
cate for 2 minutes. Lastly, take out sensor and dry it. If possible, use
a gentle stream of clean air to blow the residual liquid out of the
sensor.
5. Always re-calibrate the PID after cleaning the sensor.
2.1.3 PID Sensor / Lamp Diagnostics
In general, the strength of a PID sensor is best assessed by observing the noise level of the PID readings.
If response is noisy or weak, the unit should rst be checked for a dirty lter or sample train, and then
cleaned and calibrated as needed. The PID can still be used as long as the resolution meets the needs of
the user’s measurements, even if the diagnostic readings are outside the values given below.
PID raw signals can be accessed for aid in troubleshooting lamp/sensor problems. Connect the instru-
ment to WatchGas Suite on a PC or the mobile App, check the “Enable Diagnostic” box in the Congu-
ration screen (“General” section), and send to the instrument. The table below lists typical readings for a
new lamp, sensor and instrument.*
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10.6 eV 10.6 eV 10.6 eV 10.6 eV
PID Test Gas Raw Zero Raw Span Delta
NEO PPM MP181 Ch 1 10 ppm IBE 61000±1000 ≤50000 ≥9000
Ch 2 10 ppm IBE 61400±300 ≤61100 ≥200
Ch 1 100 ppm IBE 61000±1000 ≤500 ≥60000
Ch 2 100 ppm IBE 61400±300 ≤60000 ≥1000
9.8 eV 9.8 eV 9.8 eV 9.8 eV
Test Gas Raw Zero Raw Span Delta
NEO BENZ MP186 Ch 1 10 ppm IBE 61000±1000 ≤11000 ≥50000
Ch 2 10 ppm IBE 61400±300 ≤60500 ≥900
Ch 1 100 ppm IBE 61000±1000 ≤100 ≥60000
Ch 2 100 ppm IBE 61400±300 ≤52000 ≥9000
• First check the Raw Zero readings. If these are signicantly outside the ranges listed below, there is
probably something wrong with the sensor or circuit board.
• Apply calibration gas to the instrument. The readings should decrease by approximately the Delta
values listed below, for a new lamp. There is no set limit to the minimum Delta decrease, but com-
monly if the Delta is only 1/3 these values, the lamp is getting weak, and if it is 1/10th these values,
it is likely time to replace the lamp.
*These values are typical for a new instrument and are not to be construed as hard specications.
2.2 SAMPLING PUMP
2.2.1 Pump Service Procedures
The ow rate should be roughly 250-350 cc/min at low pump speed and 350-450 cc/min at high pump
speed when there is no air leakage. When approaching the end of its useful operating life, the pump
will consume more energy and draw signicantly lower ow. Also, if excessive dust or particles enter the
pump, the ow will be reduced. A strong pump should stall and/or nearly stop when a nger is used to
block the inlet. If the pump does not stall but the ow is weak, it is likely that particles are trapped in the
pump gasket or diaphragm. When this occurs, it is necessary to replace or rebuild the pump, or clean the
gasket. Repair of the pump requires removal of the circuit board and should be done by an authorized
service center.
1. Check for a dirty or plugged lter by removing the inlet 25-mm l-
ter and re-measuring the ow rate. Replace as needed.
2. Place a nger over the probe inlet and listen for a strain on the
pump. It should nearly stop, but may not stop completely. If the
pump tone barely changes, check the ow path, such as the inlet
probe Luer connector and sensor cap.
NOTE: The sensor cap should be screwed down only hand tight to
avoid damage to the sensor grid and possibly lamp. Typically the
green O-ring should be partially visible.
3. Check the Pump stall threshold in Conguration Mode (see NEO
User Guide). Briey block the inlet probe with a nger and observe
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the rise in pump current value, shown in the upper right. The unblocked pump current is typically
about 100-200 when set to high ow and 200-350 when set to low ow and the blocked pump cur-
rent typically rises to 500 or above. Set the stall threshold about 50-100 units above the unblocked
pump reading, but lower than the blocked pump reading.
NOTE: For NEO Benz MP186, set the stall threshold with an open (used) tube in the holder to avoid
a stall alarm when a tube is inserted for benzene measurements.
4. If the pump still gives low ow (or little strain when ow is blocked), clean the pump gasket as des-
cribed below:
Remove the sensor cap and boot
bracket (2-mm Allen wrench)
Peel o the rubber boot. Re-
move 6 housing screws (2-mm
Allen wrench)
Remove the 2 screws holding
down the circuit board (Philips
head)
Unplug the PID sensor connector
to the circuit board
Unplug the pump connector to
the circuit board
Unscrew the single screw hol-
ding down the pump
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Service Manual Photoionization Detector NEO
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Remove the sensor cap and boot
bracket (2-mm Allen wrench)
Remove the pump gasket block.
No need to remove gas connec-
tions.
Wipe clean the pump gas-
ket. It may help to remove it
(very carefully to avoid da-
mage) and clean both sides.
In some cases it helps to ro-
tate it or ip it to place the
top surface down. If dama-
ged or deformed, replace
the gasket.
In extreme cases it is necessary to
replace the pump diaphragm, or
simply replace the entire pump
During re-assembly, insert the
pump base onto the supporting
guide post before screwing down
5. When re-assembling the components, ensure that
a. the pump base is inserted onto the guide/support post
b. the pump and circuit board are screwed down securely.
c. the gasket between the front and back housing ts snugly and forms a good seal, otherwise the
housing could leak and compromise intrinsic safety.
2.3 BATTERY REPLACEMENT
1. Open the housing and disconnect the circuit board as described above for pump replacement.
2. Disconnect the battery from the circuit board as shown below.
3. Use a Size 6 Torx screw bit to remove the bracket holding down the battery.
4. Insert a replacement battery and re-assemble.
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Torx head driver to remove
battery bracket
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3. Troubleshooting
Problem Possible Reasons Solutions
Cannot turn on power after
charging the battery Defective battery Call authorized service center
to replace battery
Reading abnormally High
Dirty Filter Replace filter
Dirty sensor module Clean or replace sensor module
Excessive moisture or
water condensation Blow-dry the sensor module
Incorrect calibration Calibrate the unit
Reading abnormally Low
Dirty Filter Replace Filter
Dirty sensor module Clean or replace sensor module
Weak or dirty lamp Clean or replace lamp
Incorrect calibration Calibrate the unit
Buzzer inoperative Buzzer disabled Check that buzzer is not turned off
Bad buzzer Call authorized service center
Inlet ow too low
Pump gasket or diaphragm
damaged or has debris Call authorized service center
Flow path leaks
Check flow path for leaks;
e.g., sensor module O-ring,
tube connectors, Teflon tube
compression fitting
“Lamp”alarm on during
operation
Lamp drive circuit Turn unit off and back on
Weak or defective PID Lamp Replace UV Lamp
PC does not recognize
instrument Wrong cable Use WatchGas USB cable P/N M-011-3003-
000
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WatchGas B.V.
Sextantstraat 61
2901 ZZ Capelle aan den IJssel
+31 (0)85 01 87 709
The Netherlands
info@watchgas.eu - www.watchgas.eu
D e t e c t i on
V1.0
3. Replacement Parts
Description Part Number List Price
Lamp (10.6 eV, 3/8 inch dia.)
Lamp (9.8 eV, 3/8 inch dia.)
PID Sensor for NEO series
Lamp cleaning and tool kit
Metal sensor cap with Luer connector
Tube Holder Probe for MP186 separation tubes
Luer connector for inlet or outlet port, stainless steel
Water Trap Filters, female Luer/Luer slip for NEO (10-pk)
Water Trap Filters, female Luer/Luer slip for NEO (100-pk)
AC Charging adaptor - 1 Port with USB cable
USB Charging and communications cable
Rubber boot (Blue)
Rubber boot (Black)
Rubber boot (Red)
Battery pack for NEO Series (must be installed by authori-
zed service center)
Pump Assembly for NEO MP18X Series
Pump rebuild kit (3 oval gaskets and 1 piston diaphragm)
LCD Display for POLI MP400 & NEO MP18X Series (raw LCD,
10 pcs each)
LCD Assembly for NEO MP18X Series (includes casing, 1 pc)
Housing base and cover assembly replacement for NEO
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