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Onix tubing

The rep for Watts Radiant in central Ohio is Steffens Shultz- their web site is www.steffens-shultz.com. They should be able to hook you up with a distributor. Hope this helps.


  • SM
    SM Member Posts: 37
    onix tubing

    I am looking for a supplier for Onix tubing. I am in Ohio. Please email me. What would be the pros and cons of 200ft coils of 3/8" or 300ft coils of 1/2"? Also, doing 2000 sq ft ranch, owner just wants one zone. thinks of running 1" copper supply and return to limit the excess tubing. Any problems with this? Porbably do a reverse return so no balancing valves are needed.

  • dann crist_2
    dann crist_2 Member Posts: 37

  • dann crist_2
    dann crist_2 Member Posts: 37

    Scott, I have been using Heatway's (now Watts) tubing since the entran II days and I really l;ove working w/ it. 200's or 300's either way but the 3/8 200's is what I use almost entirely, it covers easily w/ gypcrete at about 1 1/4" and is easy to handle. I like the 200's also because except for very unusual cases, I maintain all my loops at equal lengths thereby eliminating balancing headaches. Sometimes I have to "eat up" some footage in a zone to keep the loops equal, so dividing a space into 200 foot "blocks" works best for me. It seems to be working fine this way. I don't know who supplies it in your area, but the Watts regulator people will steer you right. As for Running header and return lines to the manifold-- I do that frequently.
  • joboli
    joboli Member Posts: 4
    Onix tubing suppliers

    Here are a few links to suppliers that do mail order for Onix, and a PDF product sheet from Onix which really gives a good comparison of the product vs PEX. This was the information that convinced me to go with Onix.




    Was wondering if you could give me some advice too.

    I am in the process of planning out a staple up for my den which is 108 sq feet . The room currently is heated to "cold 70" by a radiator which separates this room from the kitchen. Room is above a crawl space, has 1 bay window, 11' cathedral ceiling, 2 sky lights, 3 exposed walls but well insulated.

    I can run a loop under the floor about 180 feet. The boiler is 32' away. Boiler supplies 2 other zones (radiator and fintube) 160 water temp. Here are a fews questions I've been pondering:

    1) Since this is a small loop, can I get away with one circulator? or should I stick with primary secondary (2 pumps)?

    2)3 way or 4 way mixing valve? I suppose I should protect my beloved old cast Iron boiler from shock with the 4 way valve and a controller.

    3) 3/4" copper to and from the boiler for the 32' run?

    I've been reading up on all this for some time now and it seems like there are thousand ways to do this so any thoughts or advice is much appreciated.

    Best regards

    Joe Sinacore
  • Tim Ritter_2
    Tim Ritter_2 Member Posts: 10
    Your questions... from a former Heatway guy

    Joe -
    Though I have been out of radiant for a few years, I hope you don't mind me passing along some thoughts.

    1. I would always go with primary/secondary, especially on a mixed system like you have. Even though it's only 180 feet of tubing for a single room, it's still best to have some control over that area. By the way, what's your floor covering?

    2. 3-way mixing is fairly economical. 4-way is the cadillac way to do it, but there is a higher cost with it. Either one, by piping primary/secondary, will protect your boiler. I guess the big question is how much you want to spend, and how far you want to go with controls.

    3. 3/4" copper should be just fine for 32'. Just remember that if you were to be looking at a longer distance, you have to remember that you double that distance for checking pressure drop in piping. 32' from the boiler room to the zone, and 32' back to the boiler room from the zone. So it's really 64' that you are looking at. Still not a big deal for 3/4" copper.

    Just my suggestions. Your local distributor will be able to help you further and can verify everything for you once and for all.

    Kinda nice to talk radiant again....

  • heatboy
    heatboy Member Posts: 1,468
    It all comes down to GPM.

    What is the load of the area? That will tell you what the flow rate will be. I have 1/2" loops as short as 160' and as long as 350' because of GPM requirements. Once you know that, you can caculate the pressure drop through the system. Having never used rubber hose of any kind, I don't know what the drop is, but I would imagine it's much higher than PEX per foot.

    Is this joist bay heating? 3/8" will mean larger manifolds and more of them. You have to weigh out the costs before deciding which size tubing to run.


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