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Fiberglass pipe insulation PVC fitting covers

ChrisJ Member Posts: 15,664
I keep running into this issue and I'm hoping there is a professional looking solution. I have a 3" to 2" reducing elbow and I have insulation on both sides and want to cover it. Of course the 3" side fits good but I have a big gap around the 2" side. How do you deal with this? Just leave it wide open?

Also, why was I supplied with vapor barrier strips similar to the jacket on the insulation? I would assume this is only a concern when insulating something that is cold and may condensate but not a concern on steam piping?
Single pipe quasi-vapor system. Typical operating pressure 0.14 - 0.43 oz. EcoSteam ES-20 Advanced Control for Residential Steam boilers. Rectorseal Steamaster water treatment


  • hvacfreak2
    hvacfreak2 Member Posts: 500
    edited October 2015
    Cut a piece of 3 inch longer than what is needed for the 90. Remove layers from that piece to go around the 2 inch. Install the piece and the 90 , use white mastic on the exposed cut end to seal.

    Suppliers usually provide cut tape as a courtesy , sort of like a merchant coupling on pipe sections.

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