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Oil tank top suction/return line connection - new HIWR thermoplastic vs old brass: pros vs cons

belham Member Posts: 32
edited February 2018 in Oil Heating
Ok, I am faced with two choices here for the fitting connection (on top of my underground tank, that resides in a 2' by 2' manhole area) that reaches two feet down into the ground reaching my underground 3000l tank.

For some reason, which I am uncertain of, German, Dutch, French (Europe overall) manufacturing gasoil equipment companies have begun, over the past several years, offering 'high-impact, weather-resistant (HIWR) thermoplastic' fitting devices for the tops of gasoil storage tanks (above-ground and/or below-ground levels). This is true whether if you have an old-style steel/aluminum tank and/or a new tank made of out other materials. Specifically for this tank top connection, is this (offering HIWR) an advance ahead of the old trusty brass or stainless steel stuff?

I have to choose between to the two below before I order them: same company (Afriso), but one is the brass offering (~$30) and the other is the newer HIWR thermoplastic ($~50). Can I ask some of you more experienced guys which you'd install (assuming you hand an underground tank like mine) if you were replacing this fitting/device? I am curious why would companies be going this route? Cost? Or is it actually a better product?? The HIWR has galvanized steel 3/8" steel sleeves inserted in the thermoplastic ports for both the "suction" and return" lines to screw your compression fitting into. But, dang, being as old as I am, all I've ever known (in terms of reliability) is that brass is the thing when it comes to stuff like this.

Thank you for your thoughts, hints, advice, etc.


  • Ignatz
    Ignatz Member Posts: 16
    Over here, we have a tank option called a STI P3 tank. Most were single wall, but there were double wall STI P3 tanks.
    STI is.....Steel Tank Institute
    P3 is three ways
    First.....the steel tank is coated with a protective coating.
    Second......the tank has anodes on the sides to make the steel tank "more negative" electrically, to protect it from corrosion. all the tank top connections, there are di-electric bushings (like plastic) to keep the "extra" negative charge isolated at the tank.
    I would say the plastic fitting on your tank is to isolate the tanks electrical charge.
    Corrosion testing was interesting, over here, a STI P3 tank gets tested every three years.
    EBEBRATT-Ed Member Posts: 9,683
    @Ignatz your talking tank construction, I think the op is asking about fittings.

    @belham, I am old school so I would pick brass. Plastic would not be allowed here as far as I am aware. But if the plastic is made for oil and in common use over there I wouldn't hesitate to use it
    HVACNUT Member Posts: 4,084
    Roth used a similar set up with the valve and floating pick up line. No longer because of problems. I would just use a double tap bushing, 1 pipe with a Tiger Loop Ultra.