SKC chek-mate 375 series User manual

skcinc.com Form 39013 Rev 210827 Page 1
chek-mate Flowmeter
Cat. No. 375 Series
Operating Instructions
Figure 1. chek-mate Flowmeter Overview
INTRODUCTION
Description
The chek-mate® Flowmeter (Figure 1) is designed specifically for use with air sample pumps and is
available in three models as described below:
•High Flow chek-mate Flowmeter with CalChek Cat. Nos. 375-50300N, 375-50300, and
375-50300S –Flow measurement range of 5 to 30 L/min and CalChek capability. Volumetric
accuracy is 1% of reading for 5 to 30 L/min. The CalChek serial interface enables direct
communication with CalChek-ready pumps in the chek-mate flow range for single-point (single)
and multiple-point (full) automatic flow calibration.
•Medium Flow chek-mate Flowmeter with CalChek Cat. Nos. 375-0550N, 375-0550, and
375-0550S –Flow measurement range of 0.5 to 5 L/min and CalChek capability. Volumetric
accuracy is 1% of reading for 0.75 to 5 L/min and 2.5% of reading for 0.5 to 0.75 L/min. The
CalChek serial interface enables direct communication with CalChek-ready pumps in the chek-
mate flow range for single-point (single) and multiple-point (full) automatic flow calibration.
Back view
Battery compartment
cover
Battery
Front view
LCD screen
Outlet
Low battery
indicator
Inlet
On/off button
CalChek interface socket
(high flow and medium flow
models only)

skcinc.com Form 39013 Rev 210827 Page 2
•Low Flow chek-mate Flowmeter Cat. Nos. 375-00205N, 375-00205, and 375-00205S –Flow
measurement range of 20 to 500 ml/min. Volumetric accuracy is 1% of reading for 50 to
500 ml/min and 2.5% of reading for 20 to 50 ml/min.
Checking Flowmeter/Kit Contents
Use the table below to verify that you received all items associated with the Cat. No. ordered. If you are
missing items, contact SKC at 800-725-8472 (U.S. only) or 724-941-9701.
If You Ordered Cat.
No.
Your Package Should Contain
375-50300N
Flowmeter, 5 to 30 L/min, with 9-volt alkaline battery and NIST standard
traceable calibration certificate
375-50300
Flowmeter, 5 to 30 L/min, with 9-volt alkaline battery and UK standard traceable
calibration certificate
375-50300S
Flowmeter, 5 to 30 L/min, with 9-volt alkaline battery and ISO standard
traceable calibration certificate
375-0550N
Flowmeter, 0.50 to 5 L/min, with 9-volt alkaline battery and NIST standard
traceable calibration certificate
375-0550
Flowmeter, 0.50 to 5 L/min, with 9-volt alkaline battery and UK standard
traceable calibration certificate
375-0550S
Flowmeter, 0.50 to 5 L/min, with 9-volt alkaline battery and ISO standard
traceable calibration certificate
375-00205N
Flowmeter, 20 to 500 ml/min, with 9-volt alkaline battery and NIST standard
traceable calibration certificate
375-00205
Flowmeter, 20 to 500 ml/min, with 9-volt alkaline battery and UK standard
traceable calibration certificate
375-00205S
Flowmeter, 20 to 500 ml/min, with 9-volt alkaline battery and ISO standard
traceable calibration certificate
375-50300-KN
High Flow chek-mate Kit, 5 to 30 L/min, includes flowmeter, 9-volt alkaline
battery, NIST standard traceable calibration certificate, and Pulsation
Dampener Cat. No. 375-150
375-50300-KNS
High Flow chek-mate Kit, 5 to 30 L/min, includes flowmeter, 9-volt alkaline
battery, ISO standard traceable calibration certificate, and Pulsation Dampener
Cat. No. 375-150
375-0550-KN
Medium Flow chek-mate Kit, 0.50 to 5 L/min,includes flowmeter,
9-volt alkaline battery, NIST standard traceable calibration certificate, and
Pulsation Dampener Cat. No. 375-100
375-0550-KNS
Medium Flow chek-mate Kit, 0.50 to 5 L/min,includes flowmeter,
9-volt alkaline battery, ISO standard traceable calibration certificate, and
Pulsation Dampener Cat. No. 375-100
Required Equipment
✓¼-inch ID tubing for low and medium flow chek-mates
✓3/8-inch ID tubing for high flow chek-mate

skcinc.com Form 39013 Rev 210827 Page 3
GETTING STARTED
Notes and Cautions
•Allow chek-mate to equilibrate for at least 10 minutes after moving it from one temperature
extreme to another beforeuse.
•The chek-mate case is rated IP40, not as waterproof or splashproof; do not use it where
water can enter thecase.
•Ensure that fluids do not enter either the inlet or outlet.
•Protect the chek-mate from direct exposure to sunlight to prevent it from heating thecase.
•Avoid extended use of the chek-mate in areas with high levels of airborne particulates. If this
cannot be avoided, use an external inlet filter with high collection efficiency (i.e., one that
collects the majority of all dust particles) and low back pressure. SKC does not supplythis.
•Use only the specified disposable or rechargeable battery types.
•Ensure that discharged batteries are not left in the battery compartment for long periods to
prevent damage caused by electrolyte leakage.
•There are no user-serviceable parts in the chek-mate flowmeter. Opening the chek-mate
case will void the product warranty and could affect the instrument calibration. An anti-tamper
warning label is fitted to the case to indicate that the case has beenopened.
•Failure to follow these guidelines will void the warranty.
Turn On/Off
Allow the chek-mate to equilibrate for at least 10 minutes in the location where it
will be used to ensure that it has stabilized to ambient temperature.
To turn the chek-mate on or off, press the on/off button on the front. See Figure 1.
Read Battery Status on LCD
When the battery voltage drops below 8 volts as it nears the end of its life, “LOW BATTERY”will be
displayed in the upper left corner of the LCD (Figure 1). Replace the battery. See Maintenance.
When the battery voltage drops below 7 volts, the “LOW BATTERY”message displayed on
the LCD will flash on and off and the chek-mate will turn off automatically. If the chek-mate
is turned on again with the battery still in this condition, the LCD will display "bAtt LO”10
times and then turn off automatically.

skcinc.com Form 39013 Rev 210827 Page 4
OPERATION
Set/Calibrate Flow Rate
•Allow the chek-mate to equilibrate for at least 10 minutes after moving it from one temperature
extreme toanother.
•Protect the chek-mate from direct exposure to sunlight to prevent it from heating thecase.
•Ensure that fluids do not enter either the inlet or outlet.
•Avoid extended use of the chek-mate in areas with high levels of airborne particulates. See Notes
andCautions.
•chek-mate does not zero the flow reading at startup, so you can turn it on with the sample train
already connected and airflow passing through the flowmeter without affecting the accuracy of the
flow reading.
•To achieve the highest possible accuracy when calibrating pumps with flow rate ≥ 5 L/min,
Pulsation Dampener Cat. No. 375-150 is always required in line between the flowmeter outlet and
the calibration train inlet.
1. Turn on the flowmeter. The LCD screen will cycle through startup messages, “On” followed by the
upper limit of the flowmeter range (“30 L” for high flow model, “5.0 L” for medium flow model,
or “0.5 L” for low flow model) and will then indicate the current flow rate or “ ” if there is no
airflow or the flow rate isbelow the minimum display value. Note: Minimum display value
depends on the atmospheric conditions, but at 68 F (20 C) and 1 atm (1013.25 mbar), values are
5 ml/min for low flow model, 0.3 L/min for medium flow model, and 3 L/min for high flow
model. Minimum display values will behigher when the flowmeter is used at higher altitudes and
temperatures.
2. Prepare the calibration train. Connect the flowmeter outlet to the calibration train inlet (Figures 2
and 3):
a. For medium flow and low flow models, use flexible 1/4-inch ID tubing, and if required
by the sampler, a calibration adapter. See Figure 2.
Figure 2. Medium Flow Calibration Train
Representative
sample medium
Pump inlet
Flowmeter
outlet

skcinc.com Form 39013 Rev 210827 Page 5
b. For high flow model, use flexible 3/8-inch ID tubing and place Pulsation Dampener Cat.
No. 375-150 in line between the flowmeter outlet and representative sample medium
inlet. If required by the sampler, use a calibration adapter. See Figure 3.
Note: If a cyclone or similar size-selective sampler does not have a calibration adapter, see
optional Jarless Calibration Method.
3. Start the sample pump and observe the flowmeter LCD until it shows a steady value. The reading
may vary around the steady value by up to ±0.05 L/min on the high flow model,
± 0.005 L/min on the medium flow model, and ± 0.5 ml/min on the low flow model. If the flow is
fluctuating, calculate and display the average flow value by activating the Average Display
function*:
a. Press and hold the on/off button for several seconds. “AVE” and then “On” will be
displayed on the LCD screen. The current flow rate will be recorded every 3.5 seconds
for 10 readings. “AVE” will appear briefly on the LCD screen followed by the average flow
value of those 10 readings. The average will be displayed for 7.5 seconds and then a
new cycle of readings will begin. This sequence takes approximately 45 seconds.
b. Reset the average reading at any time during a cycle, press and hold the on/off button for
several seconds. The next 10 readings will be used to calculate the average flow.
c. To cancel the Average Display function, turn off the flowmeter by briefly pressing the
on/off button and then turn it on again.
Run the pump for a minimum of 5 minutes to stabilize before adjusting the flowrate.
4. Adjust the sample pump to reach the desired sample flow rate.
5. Disconnect the tubing from the flowmeter outlet, taking care not to twist the tubing.
6. Turn off the flowmeter.
* For older models without Average Display function, determine the average flow value in one of two
ways: observe the highest and lowest readings and calculate the average of these two readings OR
record ten flowmeter readings and calculate the average of thereadings.
Figure 3. High Flow Calibration Train
Pulsation
dampener
Pump inlet
Flowmeter
outlet
Representative
sample medium

skcinc.com Form 39013 Rev 210827 Page 6
Jarless Calibration Method (Optional)
If a cyclone or similar size-selective sampler does not have a calibration adapter, attach the sample pump
to the chek-mate outlet (suction port) with Pulsation Dampener Cat. No. 375-100 for medium flow
chek-mate or Cat. No. 375-150 for high flow chek-mate in line between the pump and flowmeter.
Attach the sampler/media to the chek-mate inlet using the shortest length of tubing possible. Proceed with
calibration per the instructions above and pump operatinginstructions.
Perform CalChek Calibration (Medium Flow and High Flow chek-mate Models Only)
•CalChek Communication Cable Cat. No. 375-200 is required for automatic flow calibration of
AirChek TOUCHand Leland Legacypumps.
•CalChek Single-point (Single) Calibration requires sampling media in line. High Flow chek-mate
Flowmeter Cat. Nos. 50300N, 50300S, and 375-50300 also require Pulsation Dampener Cat. No.
375-150 in line between the flowmeter outlet and calibration train inlet.
•CalChek Multiple-point (Full) Calibration automatically calibrates the pump across its entire
operating range and so is performed without sampling media in line; instead, install Pulsation
Dampener Cat. No. 375-100 for medium flow chek-mate or Cat. No. 375-150 for high flow chek-
mate between the flowmeter andpump.
1. Preparethe pump perpump operatinginstructions.Note: For AirChek TOUCH pump, ensure that
the appropriatepower supply isinstalled on the pump charging cradle and the pump is seated
correctly in the cradle.
2. Turn on the flowmeter.
3. Connect the CalChek Communication Cable to the flowmeter and the pump.
a. Install one connector end of cable into CalChek interface socket on flowmeter.
Automatic Power Off Timer —chek-mate will remain on indefinitely provided that
a flow rate higher than the minimum display value (see Step 1 above) is indicated.
With a flow rate lower than the minimum display value or noairflow (“ ” indicated
on the LCD), the flowmeter will automatically turn off after 15 minutes to preserve
battery power.

skcinc.com Form 39013 Rev 210827 Page 7
b. Install other connector end of cable into CalChek port on back of charging cradle
(or e-Cradle) for AirChek TOUCH pump or into data port on top of Leland Legacy pump.
4. Prepare appropriate CalChek single or full calibration train (see Figures 4 through 7). Note: Use
1/4-inch ID flexible tubing for AirChek TOUCH and 3/8-inch ID flexible tubing for Leland Legacy.
Use a calibration adapter if required.
CalChek Single Calibration Trains
AirChek TOUCH charging cradle CalChek port
Data port
Leland Legacy data port
Representative
sample medium
CalChek
cable
Flowmeter
outlet
Power
supply
Pump inlet
Figure 4. CalChek Single Calibration Train (AirChek TOUCH Pump)
Figure 5. CalChek Single Calibration Train (Leland Legacy Pump)
Representative
sample medium
Pulsation dampener
Flowmeter
outlet
Pump inlet
CalChek cable

skcinc.com Form 39013 Rev 210827 Page 8
CalChek Full Calibration Trains
5. Initiate CalChek function from the pump per pump operating instructions.
6. When airflow through the flowmeter is detected, it automatically produces its flow rate reading via
the CalChek serial interface at 3.5-second intervals. The pump will automatically read in the flow
readings as required to complete the CalChek process and will indicate completion on its screen
display.
Figure 6. CalChek Full Calibration Train (AirChek TOUCH Pump)
Flowmeter outlet
CalChek
cable
Power
supply
Pump inlet
Pulsation dampener
375-0550
FLOW CALI BRATOR
FOR AIR SA MPLING PUMP S
0.5 - 5.0 litre/min
S/No185 44134
CALIBRATE UNDER VACUUM
MANUFACTUREDBYSKC LIMITEDUNDER A
SOLELICENSE FROM GRAHAMBLATCHFORD
www.skcltd.com
Figure 7. CalChek Full Calibration Train (Leland Legacy Pump)
CalChek cable
Pulsation
dampener
Pump inlet
Flowmeter outlet

skcinc.com Form 39013 Rev 210827 Page 9
MAINTENANCE
If the chek-mate is not going to be used for an extended period, remove the battery from the
battery compartment. Deep discharge of alkaline batteries can result in the eventual
leakage of battery electrolyte even from quality batteries and can corrode the battery
compartment terminals and potentially the flowmeter printed circuit board.
Replace the Battery
•SKC recommends using quality alkaline batteries to ensure long battery life and prevent damage
due to leaking battery electrolyte. A quality battery such as the Duracell Industrial model supplied
with the chek-mate should provide as many as 30 hours ofoperation.
•If using a rechargeable battery, it must be 8.4-volt NiMH. See Performance Profile for
specifications.
•Failure to follow these guidelines will void the warranty.
When the battery voltage drops below 8 volts as it nears the end of its life, “LOW BATTERY”will be
displayed in the upper left corner of the LCD. Replace the battery as follows:
1. Unscrewthetwocaptivescrews securingthebatterycompartmentcover using asmallPhillipshead
screwdriverandremovethe cover.
2. Lift the old battery straight up and out of the battery compartment.
3. Insert the replacement battery into the compartment, ensuring that the terminals are oriented
correctly as shown on the label at the bottom of the compartment.
4. Insert the battery compartment cover and secure it with the two captive screws. Do not
overtighten the screws.
When the battery voltage drops below 7 volts, the “LOW BATTERY”message displayed on
the LCD will flash on and off and the chek-mate will switch off automatically. If the chek-
mate is turned on again with the battery still in this condition, the LCD will display “bAtt LO”
10 times and then turn off automatically.
Calibrate the Flowmeter
SKC recommends a minimum calibration interval of one year, however, users are responsible for
determining the most suitable interval to meet their quality assurance system requirements; they should
also consider the frequency of use and operating environment.
Calibration Method
The chek-mate is designed primarily to perform flow calibration of air sample trains that incorporate an air
sample pump to provide the airflow, therefore the airflow is pulled through the chek-mate by the vacuum
generated by the air sample pump. To ensure that the SKC factory flow calibration is representative of
how the chek-mate is actually used, the flow calibration is performed under vacuum. Factory calibrations
are performed with the chek-mate connected in series with the referenceflowmeter.
SKC recommends that subsequent flow calibrations of the chek-mate flowmeter are also performed under
vacuum and with the chek-mate connected in series with the reference flowmeter. However, positive
pressure flow calibration using compressed laboratory air or nitrogen gas is also acceptable, with the
chek-mate connected in series with the reference flowmeter.

skcinc.com Form 39013 Rev 210827 Page 10
SKCCAL Serviceoffers calibration anddocumentationfor thechek-mateand otherflowmeters.The SKC
CalibrationLaboratory will calibrate the chek-mate at predefined flow rates. NIST-traceable and ISO/IEC
17025:2017 services are available. Order SKC CAL Service at www.skcinc.com/skccal.
Important notes/recommendations for third-party flow calibrations:
•Install a new battery in the chek-mate before sending it for third-party calibration.
•Enclose a copy of these instructions with the chek-mate when sending it to a third-party
calibration laboratory.
•Airflow is indicated in ml/min on Cat. Nos. 375-00205N, 375-00205S, and 375-00205 and in L/min
on Cat. Nos. 375-0550N, 375-0550, 375-0550S, 375-50300N, 375-50300, and 375-50300S at the
current ambient temperature and atmospheric pressure, therefore, the reference flow
measurement must be corrected to these conditions for comparison with the chek-mate indicated
flow reading.
•Factory flow calibration is performed under vacuum, therefore, the calibration gas used is ambient
air with relative humidity of 50 ± 20%. When performing positive pressure flow calibrations using
compressed dry laboratory air or nitrogen gas, correct for the difference in gas density.
•When performing flow calibration under vacuum with the chek-mate connected in series with the
referenceflowmeter, connect the chek-mate with its inlet open to atmosphere.
•When performing flow calibration under positive pressure with the chek-mate connected in series
with the reference flowmeter, connect the chek-mate with its outlet open to atmosphere.

skcinc.com Form 39013 Rev 210827 Page 11
ACCESSORIES/REPLACEMENT PARTS
CalChek Communication Cable, required for automatic
calibration of AirChek TOUCH and Leland Legacy Sample Pumps 375-200
Pulsation Dampener, required for use with Cat. Nos. 375-0550N,
375-0550, and 375-0550S for CalChek full calibration of AirChek TOUCH
Sample Pumps 375-100
Pulsation Dampener, required for use with Cat. Nos. 375-50300N,
375-50300, and 375-50300S for calibration of high flow pumps and
CalChek calibration of Leland Legacy Sample Pumps 375-150
Battery, 9-volt alkaline P37500
SKC Limited Warranty and Return Policy
SKC products are subject to the SKC Limited Warranty and Return Policy, which provides SKC’s sole liability and
the buyer’s exclusive remedy. To view the complete SKC Limited Warranty and Return Policy, go to
skcinc.com/warranty.

skcinc.com Form 39013 Rev 210827 Page 12
APPENDIX
Performance Profile
Flow Measurement
Range
High flow: 5 to 30 L/min
Medium flow: 0.5 to 5 L/min
Low flow: 20 to 500 ml/min
Airflow Display
Resolution
High flow: 0.01 L/min
Medium flow: 0.001 L/min
Low flow: 0.01 up to 100 ml/min and 0.1 above 100 ml/min
Airflow Accuracy
± 1% of reading for 5 to 30 L/min (high flow), 750 to 5000 ml/min (medium flow), and
50 to 500 ml/min (low flow)
2.5% outside of above ranges for medium flow and low flow models
Operating Temperature
Range
32 to 104 F (0 to 40 C)
Operating Atmospheric
Pressure Range
20.7 to 32.2 in Hg (700 to 1090 mbar)
Operating Altitude
Sea level to approximately 10,000 ft (3050 m) above sea level
Dimensions
7.1 x 3.3 x 1.3 in (18 x 8.3 x 3.3 cm)
Weight
High flow: 8.6 oz (244 gm)
Medium flow: 8.3 oz (236 gm)
Low flow: 8.2 oz (232 gm)
Tubing
Medium and low flow: Requires 1/4-in ID tubing
High flow: Requires 3/8-in ID tubing
Enclosure IP Rating
IP40
Power Supply
9-V alkaline (disposable) PP3/6LR61/1604A or equivalent - should provide
30 hrs of operation; or 8.4-V NiMH (rechargeable) PP3/6HR1/8.4H5 or
equivalent
Low Battery
When battery voltage drops below 8 V, LCD displays LOW BATTERY.
Low Battery Fault
When battery voltage drops below 7 V, flowmeter shuts down.
Automatic Power Off
Timer
15 min
Certifications
CE marked