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smithde
Registered Users
Posts:2
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| 03/27/2006 2:50 PM |
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I am running 7/8 radiant pex form Radiantec through the basement concrete, under the first floor (stapled) and under the 2nd floor.
My question: Is it OK to run 3/4" pex(which seems to have quite a bit smaller inside circumference than my 7/8" ciruit runs) for my supply and return from and to the water heater(Polaris).
Thank you
Coach Smith
Lynchburg, VA |
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NRT.Rob
Registered Users
Posts:386
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| 03/27/2006 3:22 PM |
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Can't say for sure without knowing your heat loads and flow rate requirements. You can push roughly 25kBTUs-50kBTUs/hr through 3/4" figuring a ten or twenty degree temperature drop respectively. That's 5GPM.
I believe there may be code issues with running PEX right to a water heater in some jurisdictions though, so you might want to check that as well.
I can say you will not have fun running that pipe in the 1st and 2nd floors, and you should instead use double runs of 1/2" pipe. This will be much, much easier to install, and it will give you a better system to boot... more even floor temps, and lower operating temps. Final cost should be similar. especially once you figure in repair couplings for the 7/8" which will kink and break on you ;)
I also sincerely hope you are installing a heat exchanger. Very bad idea not to do this.
Finally, if that's a finish basement, keep your tubing on centers to 12" or less. Otherwise you will know where the pipes are when you are walking around.
-=Northeast Radiant Technology, LLC=-
www.NRTradiant.com |
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-=Northeast Radiant Technology=-
NRTradiant.com |
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smithde
Registered Users
Posts:2
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| 03/28/2006 8:57 AM |
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NRT.Rob - thank you for your help. I have already run the 7/8" circiuts and you are right, it did kink on me twice. I am new to all of this, but so far it has'nt been too bad.
I do plan on running copper all the way through the pumps and to the ceiling, but then make the transition to the 3/4" pex for the supply and return. The circuits (11) are 200 foot runs on the first and 2nd floor and (4)300 foot runs in the concrete slab. The heat source is a gas Polaris 50 gal 130K BTU. I am not sure if using the smaller pex (interior diameter is about 5/8") is going to be a problem.
Thanks again.
Coach Smith
Lynchburg, VA |
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NRT.Rob
Registered Users
Posts:386
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| 03/28/2006 10:12 AM |
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It sounds like you're probably well over what you can do with 3/4" pipe. However if you did a primary/secondary arrangement, you might be able to make it work if your operating temps are significantly lower than your water heater setting.
-=Northeast Radiant Technology, LLC=-
www.NRTradiant.com |
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-=Northeast Radiant Technology=-
NRTradiant.com |
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