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Oatey offers a #47700 Underdeck Clamp Kit that is recommended for every roof drain installation. This clamp is placed below the roof and attached to the drain body with 4 pieces of threaded rod, and 4 nuts. Once installed the clamp will secure the drain body in place so that the waterproofing seal is less likely to be compromised. 

No. Waterproofing materials can only be applied in series with our flanged drain assemblies. Please visit our website to select the right drain for your project. 


  • Outside diameter   29¾” x 31¾”
  • Inside diameter   27-11/32” x 29-11/32”
  • Depth   2-19/32” 

Yes. The #34169 – 28”x30” pan does not have ribs.

No. It is very unlikely that you would be able to create a watertight patch, and this would void any manufactures warranties. If you need a pan without holes for your application, we offer several pans for you to choose from:

  • 22” Plastic Pans #34066 do not have holes stamped into them.
  • Aluminum Pans are available without holes in all sizes.

28 gauge or .032”

Plastic and aluminum pans are available in the following sizes:

  • 18” / 20” / 22” / 24” / 26” / 28” / 30” and 32” 
    • Make note that these are interior dimensions and the exterior dimensions for each pan size is plus 1”  

The standard depth for the aluminum and plastic pans is 2½”.

  • We also offer 3” deep plastic pans in all sizes for those areas where 3” depth is required. 3” deep pans are only available in 18” / 20” / 22” / 24” / 26” / 28” and 30”

We offer 3 different fitting adaptors for our pans:

  •  #34086 - 1” inside & 1½” over PVC Adaptor. This adaptor allows you to solvent weld a piece of 1” PVC or a piece of 1½”PVC pipe into the adaptor.
  • #34088 – 1” inside & 1½” inside PVC Adaptor. This adaptor allows you to solvent weld a piece of 1” PVC pipe into the adaptor, or solvent weld a 1½” PVC fitting hub onto the adaptor.
  • #34089 - 1” CPVC adaptor. This adaptor allows you to solvent weld a piece of 1”CPVC into the adaptor hub.

If you need further clarification on these installation options, please contact customer service and they can send you an illustrated copy of application instructions.

You should always check with your local building and fire officials before installing a plastic
pan above a finished ceiling. If the return air to the furnace is not isolated through air tight
duct work or the open ceiling is used for the return air, the plastic pan should never be used. If
the plastic pan is used in these applications and exposed to flames, the toxic smoke can be
drawn back to the furnace and distributed throughout the building.

The plastic pan is not approved for gas water heater installations, and the aluminum pan must
be used. The plastic and aluminum pans are approved for electric water heater installations.

3.5 PSI with less than a 1 PSI pressure loss over the time period called out in the tables.  

5 seconds

Concrete pipe is porous and the ASTM guidelines give allowances for this porosity. 

Owner’s Manuals and parts lists on all Cherne equipment can be located in the technical section of the Cherne website. “pieces parts” – replacement parts for the hydrostatic test pumps and joint testers. We do not stock engine parts.  


This calculation is important to the end user and helps them understand the forces behind the plug so that they can decide the proper way block the plug.

Backpressure is measured either in terms of feet of head or psi.  

  • Feet of Head. Simply stated “feet of head” is the height of water above the centerline of a plug. For vertical pipe the calculation is easy. Simply measure the height of the pipe and that is the footage of head pressure. For horizontal pipe, feet of head is still simply the height of water above the plug. There are various ways to determine this height base on knowledge of the actual application. For example, if you have a 300’ long section of pipe at a 1 degree slope, the feet of head is 3’. (300*.01)
  • PSI - This measurement is typically done with a pressure gauge.
  • #’s (pounds) of Force. This is the calculation to determine how much force is being held back by a plug. It is useful information when trying to design a plug blocking system for a specific job.
    • Calculating pounds of force for air pressure tests.  
      • PSI *square inches of pipe opening = #’s of force
        • Example:  8” and 5 psi test.  Pipe area = Pi R2 * (3.14*42=.50.24”).  50.24” * 5 PSI = 251.2 #’s of force.
    • Calculating pounds of force for head pressure applications.
      • Convert Feet of Head to PSI and then do calculation above.
        • PSI = Feet of Head *.434.
        • Example:  8” pipe at 30’ of head.   Pipe area = Pi R2 * (3.14*42=.50.24”) 30 Feet of Head *.434 = 13.02 13.02 * 50.24 = 654 lbs. of force.

One foot of head to psi conversion chart is attached for your reference.  Feet of head psi ratings for each Cherne plug can be found in the Cherne catalog.

10 inches

Smoke bombs have a one year shelf life from the date of manufacture. 

Diaphragm Hydrostatic test pumps use oil in the engine, in the gear reduction unit, and in the pump itself. 30 weight motor oil is used for the engine and pump. The gear reduction unit uses 90 weight gear lube.

  • **Piston Pumps only use oil in the engine.  (30 weight motor oil.)

All of Cherne’s hydrostatic test pumps are designed to pressure test new potable water lines. Piston style pumps can be pressure fed or suction fed. 

  • Piston pumps cannot be run dry nor should they be used in conjunction with chlorine. (Chlorine is frequently used when new potable water lines are being tested to avoid contamination). 
  • Diaphragm test pumps cannot be pressure fed. However they can be used with an optional gravity feed water tank sold by Cherne, or with a large container (like a garbage can) filled with water into which the intake hose can be placed. 

Diaphragm pumps can be used with up to a 10% chlorine solution in the test water.

No. Field Scrapping products should only be defined by plumbing product manager.

Material Safety Data Sheets for smoke bombs and liquid smoke can be found in the technical information section of the Cherne website at or    

Cherne offers two poly lift lines. The poly lift line with inflator (Schrader) valve fittings can be used on any plug that has an eyebolt, and also has a inflator valve. The poly lift lines with gauge can be used with any plug that has an eyebolt, and also has a removable inflator valve fitting. 

Yes. The #012678 Tub Plug Set. 

Yes. the Iron Grip Plugs can be used for this application and comes in sizes 2”, 3”, 4”, 6”, 8”, 10” and 12.”

Both pipes have the same outside diameter. SDR 35 has a thinner wall that SDR 26.

Yes. Cherne offers the T-Handle Gripper as a flow through plug.