[time-nuts] OT Euro/US plumbing was 14 tpi UNS die
Joseph M Gwinn
gwinn at raytheon.com
Wed Jul 8 00:21:26 UTC 2009
time-nuts-bounces at febo.com wrote on 07/07/2009 05:38:52 PM:
> From:
>
> bg at lysator.liu.se
>
> To:
>
> "Discussion of precise time and frequency measurement" <time-
> nuts at febo.com>
>
> Date:
>
> 07/07/2009 05:40 PM
>
> Subject:
>
> [time-nuts] OT Euro/US plumbing was 14 tpi UNS die
>
> Sent by:
>
> time-nuts-bounces at febo.com
>
> > bg at lysator.liu.se wrote:
> >> Hi Chuck,
> >>
> >> Been living in Sweden my whole life. And almost exclusivly in houses
> >> heated by circulating hot water through radiators. I have yet to spot
an
> >> O-ring.
> >>
> >> Where in Sweden did you see this strange system?
> >
> > Hi Bjorn,
> >
> > In the US, hydronic heat comes in a couple of flavors: The old
fashioned
> > cast iron radiators, fin/coil baseboard radiators, radiant baseboard,
or
> > steel radiators/towel warmers imported from the Europe.
>
> Your description does not enlighten me... there are all sorts
> of radiators available here.
>
> > Most of the European systems are geared towards PEX tubing, and
> > compression
> > fittings... and untapered pipe thread with jamb nuts and O-rings.
>
> PEX tubing has been "certified", but Prisol tubing (ie soft bendable Cu
> with plastic "coating") is much more common here. Cu tube joints are
made
> with "nut", "support cylinder" and a "squeeze ring".
>
> > Runtal, Cordivari, Wirsbro and Wesaunard are examples I have run into.
>
> It is actually Wirsbo... ;-) The others are unknown to me.
>
> > Do you install and repair systems? Or just live with them?
>
> I do minor changes to the house system. And I have accumulated more than
> enough radiator heating seasons to know your "two seasons to
> leak" quality must be a US craftmanship problem.
The relevant US pipe-thread standards are quite clear - straight threads
are for mechanical connections only. For connections that must also
contain fluids under pressure, one uses taper threads such as the
ubiquitous NPT. Over the decades, I have lived in many houses, including
my current house, with circulating hot water heat and cast iron radiators,
and I have never had to redo a radiator connection. I've never had a
leak, and most of these systems were old when I bought the house.
If you have straight pipe threads going into radiators, there is an
installer who should be made to re-do the job. Maybe he was an
out-of-work electrician, and used rigid electrical conduit for pipe.
Straight threads and O rings are seen only in hydraulic systems, not
domestic water or heating systems, and the mating parts have correctly
designed pockets to hold the O-rings. And they do not use jam nuts. One
screws them together until they bottom.
Joe Gwinn
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