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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 ......protection 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.
    Third....at 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: 13,427
    @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: 5,023
    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.