Gentek 3940202 User Manual

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Chapter 6: Maintaining Your Filtered Enclosure

Determination of When to Replace Odor Control Carbon Filters and How to Replace

The carbon filters MUST be replaced when anyone of the following two conditions are met:

1.The filtered enclosure outlet (exhaust) concentration approaches the inlet concentration, indicating filter saturation.

2.The odor in the work area becomes intolerable or the concentration of the chemical in the work area is greater than the TWA.

There are four means of determining when its time to change the carbon filters (not shown in the order of preference).

Odor - A person’s sensitivity to odor, tolerance of odor and their comfort level under odoriferous conditions vary with the individual. While odor is an indicator that chemicals are passing through the carbon filter, several points need to be understood:

Odor within the room is not necessarily an indication of saturation or hazardous exposure concentrations.

Odor can be used as a prompt to sample the chemical concentration on the exit side of the carbon filter.

Organic chemicals approved for use in the filtered enclosure have odors that are detectable before reaching the time weighted exposure limits.

Detection Tubes - Color change indicators can be used to measure the concentration of the chemical at the exit side of the carbon filter or in the outlet exhaust. A kit including syringe pump and flexible tubing can be purchased as an accessory from Labconco (Catalog # 6924900). Labconco Customer Service Representatives are supplied with detector tube catalog numbers, as well as telephone numbers to direct you to where to purchase these items.

For Organic, Formaldehyde and Ammonia, chemical specific detector tubes should be purchased when installing fresh filters. Each kit contains instructions on how many strokes of the syringe are required to obtain the stated sensitivity. The sampling syringe is connected to the filtered enclosure exhaust. Connect the syringe to the detector tube while the system is running and pull the air through the tube with the syringe. Each stroke of the


Chapter 6: Maintaining Your Filtered Enclosure

syringe represents a 100-mlsample and corresponds to the number of strokes necessary to give the indicated color changes. Due to the wide variety of organics and varying TWA’s, it is recommended that specific detector tubes be purchased directly from Sensidyne, Draeger or your laboratory supply dealer. Alternate detector pumps can also be purchased from your laboratory supply dealers. The vast majority of detector tubes available start measuring at the TWA. When a user observes a color change in the tube, they should replace the filter immediately. If no detector tube for your specific chemical is available, other means of detection must be used.

Time - For applications that have very consistent inlet concentrations and operating time, “Time” can be used to anticipate saturation or TWA levels based on prior experience. However, this does not replace the need for sampling. Consult Labconco technical specialist for an estimate of carbon filter life based on chemical usage. Detector tubes, or analytical instrumentation shouldalways be used to determine concentrations in the carbon filter. It is recommended that the carbon filters be checked with detector tubes or other means at intervals of 20% of the total estimated filter life. The exception to the 20% recommendation is formaldehyde and any carcinogen or suspected carcinogen. These more hazardous chemicals must be checked at least every 10% of the total estimated time.

Analytical Instrumentation - This is the most accurate means of measuring concentrations ofany chemical. It is the method of choice when no detector tubes are available or the tubes are not sensitive enough to measure at the TWA concentration for the chemical. This method is also to be used to determine saturation when the chemical concentration is below the measurement range of detector tubes.

Odor Control Carbon Filter Replacement Procedure – See

Figures 4-1and4-2for Carbon Filter Replacement.

1.The carbon filters are replaced by first removing the two screws, which hold the clips to secure the upper diffuser screen. Remove the screws, clips and upper diffuser screen.

2.Remove the carbon filter in a careful way to avoid the flow switch and HEPA filter.


Chapter 6: Maintaining Your Filtered Enclosure

3.Re-installthe new carbon filter with the gasket down. Replace the upper diffuser screen, clips and two screws.

4.The weight of the carbon filter with the gasket down will compress the gasket.

Calculating Odor Control Carbon Filter Life

Labconco developed a modeling program to estimate the filter life for typical carbon filters. Since filter life is dependent on the chemical used, the airflow, filter size, and the dwell time, refer to the Chemical Guide for the Paramount® Filtered Enclosure. The estimated life for Odor Control carbon filters for the filtered enclosures is conservatively calculated at 50% or half of the published values for the Paramount in the Chemical Guide. For example, if you use isopropyl alcohol to disinfect and use approximately 100 ml per week during 2 hours of use per day then follow these steps to calculate the concentration in parts per million (ppm).

Steps for Calculating PPM and Filter Life

1.Determine the amount of the proposed chemical lost to evaporation over a given amount of time. For example, if you use isopropyl alcohol and lose approximately 100 ml per week during 2 hours of use per day.

2.Convert the amount lost into ml/min. For this example:

100 ml X

1 week X

10 hours =

100 ml lost

=.17 ml/min


10 hours use

600 minutes

600 minutes


3.Convert ml/min to PPM by multiplying ml/min by the conversion factor found in the second to the last column on the right. For isopropyl alcohol .17 x 41 = 7.0 PPM.

4.Find the PPM value on the chart that comes closest to the value you just calculated in step #3. In this example, round up to 10 PPM, which is close to the calculated 7.0. We may approximate the filter life to be around 155 hours of actual use, but use 50% of this for the Odor Control filters or 78 hours.

5.Insert the estimated filter life into the estimated usage to determine how long filters will last.

78 hours filter life

=7.8 weeks before filter saturation

10 hours per week use



Chapter 6: Maintaining Your Filtered Enclosure

Formaldehyde only

For formaldehyde, use 10% of the impregnated carbon weight. Formalin is 37% formaldehyde by weight. The density of formalin is 1.08 g/ml.



Pounds of

Adsorbed weight of






Volume of


Filter Size





18 x 18 x 1


0.7 lbs./318g

796 ml


30 x 18 x 1


1.2 lbs./545g

1364 ml


42 x 18 x 1


1.68 lbs./763g

1910 ml

Ammonia only

For ammonia, use 10% of the impregnated carbon weight. Assume use of a 50% solution of ammonia for these calculations.



Pounds of







Volume of 50%



II Carbon

Adsorbed weight of



Filter Size





18 x 18 x 1


0.92 lbs./418g

836 ml


30 x 18 x 1


1.35 lbs./613g

1226 ml


42 x 18 x 1


1.89 lbs./859g

1718 ml

Initial Certification

The filtered enclosure has been certified at the factory for an inflow velocity of 90±10 fpm along with the HEPA Filter Leak Test. The filtered enclosure should be certified for the proper inflow velocity required by your Safety Officer. It is also a conservative recommendation to perform the HEPA Filter Leak Test again should there be any damage caused during transport.


Under normal operating conditions, the enclosure should be recertified at least annually if serviced. The certifier should perform the following tests.

Inflow Velocity Test

HEPA Filter Leak Test

In addition, the following tests should also be performed at the user’s discretion:


Chapter 6: Maintaining Your Filtered Enclosure

Measure of Line Voltage and Current

Smoke Test to determine proper airflow patterns

Lighting Intensity Test (when appropriate)

Noise Level Test (when appropriate)

Vibration Test (when appropriate)

Fluorescent Light Replacement

1.Disconnect the power.

2.Locate the small light reflector located under the control panel shown in Figure 6-2and Figure6-3.

3.Remove the light reflector support by removing two Phillips screws on the bottom of the light reflector.

4.Rotate and remove the old fluorescent lamp.

5.Reinstall the new fluorescent lamp and light reflector in reverse order.

6.Power the unit up and try the new fluorescent lamp.



Motorized Impeller Replacement

The motorized impeller must be replaced as a complete unit. When the motorized impeller is replaced, the capacitor may also be replaced. See Appendix A for Replacement Parts Diagram. See Figure 6-5for an isometric view of the motorized impeller plenum assembly. The HEPA filter rests on top of the motorized impeller assembly.

1.Wear appropriate personal protective equipment to decontaminate the filtered enclosure and then unplug from the electrical outlet.

2.Remove HEPA filter per the HEPA filter removal procedure outlined in this chapter.

3.Consult the wiring diagram in Appendix C of the manual and disconnect all the wires of the motorized impeller. Be sure to connect wires on the new motor in the same way the old motor was wired.

4.Remove four screws in the motor bracket that hold motor bracket to the supports with the vibration isolation mounts. Remove the motor and bracket.

!WARNING: High-speedblower. Never operate impeller with housing off.

5.Replace the capacitor with a new one of equal voltage and capacity.


Chapter 6: Maintaining Your Filtered Enclosure

6.Reassemble the new motorized impeller by reversing the assembly steps.

Figure 6-4

Motorized Impeller Replacement


Chapter 6: Maintaining Your Filtered Enclosure



Speed Control Replacement

1.Remove the bracket that the speed control is attached to. See Figures 6-1,6-2and6-3.

2.Remove the two screws holding the speed control using a Phillips screwdriver. Refer to Appendix A for Replacement Parts Diagram.

3.Disconnect all wires leading to the speed control. Connect wires on new speed control in the same position as the old speed control.

4.Reassemble to the system in the same position and with the same screws that were removed earlier.






There are several ways to accessorize and modify the filtered enclosure for your individual requirements. These include the addition of accessory work surfaces, airflow monitors; exhaust transition kits, remote blowers, exhaust dampers, filters, storage cabinets and utility shelf kit.

1. Work Surfaces

An optional dished work surface is available to attach to the filtered enclosure.

Dished work surfaces are contoured to fit the dimensions of the filtered enclosures to contain spills. Epoxy is chemical resistant. See Figure 3-1for installation.

Catalog #


Dimensions (W x D x H)


Black, 2-footwide

24" x 29" x 1"


Black, 3-footwide

36" x 29" x 1"


Black, 4-footwide

48" x 29" x 1"


Gray, 2-footwide

24" x 29" x 1"


Gray, 3-footwide

36" x 29" x 1"


Gray, 4-footwide

48" x 29" x 1"


Chapter 7: Accessorizing and Modifying your Filtered Enclosure

2. Guardian™ 1000 Digital Airflow Monitor or Guardian™ LED Airflow Monitor

The Guardian Digital 1000 Airflow Monitor or Guardian LED Airflow Monitor allows you to continuously monitor airflow through the enclosure. Either monitor is usually provided with the XPert enclosures.


Order Part #’s

Individual Parts Required

Guardian Airflow Monitor



115V or 230V




1 ea.


Airflow Monitor Printed Circuit Board

1 ea.


Airflow Sensor w/ Connector

2 ea.


#6-32x .31" Phillips machine screw to



mount Airflow Monitor Circuit Board




2 ea.


#6-32x .50" Phillips thread cutting screw to



mount Airflow Sensor







Guardian Digital 1000



Airflow Monitor




1 ea.


115V Guardian Digital Monitor, Airflow



Sensor, Sensor Cable, and 15 VDC power






1 ea.


230V Guardian Digital Monitor, Airflow



Sensor, Sensor Cable, and 15 VDC power





Add appropriate Front Panel with cutout to mount Digital

1000 Airflow Monitor


1 ea.


2' Front Panel w/ cutout





1 ea.


3' Front Panel w/ cutout





1 ea.


4' Front Panel w/ cutout

NOTE: The cutout can also be made with a reciprocating saw and a 1/8" diameter bit. The centerline of the cutout is located 3.3" from the left side and 4.2" from the bottom. The 1/8" mounting holes are spaced 4.38" apart top to bottom and centered over the cutout. The cutout dimensions are 2.43" wide by 4.13" tall.

3.Exhaust Transition Kits for Ducting to Outside

Exhaust transition connects to the XPert Filtered Balance System with integral motorized impellers from the top so the duct can be routed up and outside the building. The transition is available for 6" PVC duct. The transition should be sealed to the top of the enclosure with silicone sealant to prevent leaks. See Figure 3-3.


Chapter 7: Accessorizing and Modifying your Filtered Enclosure

Order the following:




2' Exhaust Transition Kit


3' Exhaust Transition Kit


4' Exhaust Transition Kit

4. Remote Blowers

Has a 1/4 hp direct drive motor and corrosion-resistantepoxycoated steel housing and wheel with blower inlet of 6.00" ID. Outlet dimensions are 4.25" x 7.38" OD.

CFM @ Static Pressure-Inchesof H2O











































Shipping Wt.























Remote Blower, 115 V, 60 Hz. 4.4 amps






Remote Blower, 115/230 V, 50 Hz, 5.6/2.8 amps






Explosion-ProofRemote Blower, 115 V, 60 Hz,





4.4 amps










































Figure 7-1