Buderus Panel Rads. Connecting to

Carb

I am installing Buderus panel radiators (home runs to manifold with 1/2" Fostapex) to add to cast iron radiators in a steam to hot water conversion.  I am using Buderus straight isolation valves which connect to the male R-20 on the radiator leave a male R-20 to connect to.  As I understand it, I can use compression fittings to connect to 1/2 copper or directly to the PEX but I would rather not use compression fittings.  Is there any (reasonable) way to convert the male R-20 connection to a male 1/2" NPT?  I would like to use a chrome union and nipple to drop below the floor and connect to the PEX.



Thanks for all your help.  The Wall has been a great resource for me.

kcopp

To say they....

are compression is kind of a misnomer... It is a barbed fitting w/ barbed split ring. They are pretty beefy. I did similar to what you did I just ran the Pex directly to the rad. the only isolation is at the manifold in the basement. The only issue I have ever had is one time i did not line the pex up straight as it was coming out of the wall at an odd angle. I suppose you could use the pex x copper sweat adapters and crimp them on.

Carb

Buderus Panel Rads. Connecting to

Thanks.  So I should relax a bit and stop over-thinking/ over-designing things.  I will probably connect directly to the Pex.  Are you aware of any problems connecting Fostapex (after it has been shaved down) to the Buderus PEX fittings?  Thanks Again.

kcopp

I have never ....

used Fostapex w/ that connection.

Gordan

Fostapex is SDR9

The shaved-down inner section will be like any standard PEX.



It is NOT dimensioned like other PEX-AL-PEX (which has a larger ID for the same nominal size.) Learned this the hard way when I tried to use PAP compression fittings on it.

hot_rod

adapters

there are not a lot of NPT adapters that come from Europe. Barbed pex, or compression, or a straight BSP thread are the most common.



You might find a sweat connection to fit onto that valve, from Buderus. Caleffi offers sweat fittings for their radiator H valves, but the shape of the cone taper and o-ring may not be compatible with that brand of valve.



I like Fosta pex for that type of installation, with the correct adapter.



When you strip the outer jacket from FostaPex you don't always end up with a clean pex tube exposed, I'm not sure a compression fitting would work well on that surface?



hr

Ironman

I Don't Know...

About FostaPex, but standard PAP (Roth, Kitec, Mr. Pex, etc.) is essentially the same I.D. as regular Pex in the 1/2" size and will work fine with the RS 20 x 1/2" pex compression fitting. All you have to do is tighten it a little more than with regular Pex. We do this all the time on manifolds and Buderus panel rads.