A new slant on Shop Air Piping

I have just finished the hydronic heat piping for the new house and
had a couple hundred feet of 1/2" PEX left over from the 3000 feet
purchased. The building inspector was giving me conflicting test
requirements. The installation manual says 60 psi air test and the
inspector wanted a 100 psi hydrostatic test so I got on the phone to
the manufacturer. They sent out an intallation engineer who told me
the PEX could handle a 300 psi hydrostatic test. I suggested it might
be good for shop air in that case and he said it would be just fine.
Remember this PEX is a Polyethylene compound and pretty flexible so it
won't shatter if ruptured. Its not cheap at $.52/ft in 1000 ft rolls
but what can you do with the remnants when the heating system is in.
BTW I never did perform the hydrostatic test as I hadn't quite
finished purging the air from the six water circuits when the
inspector arrived. The system had held steady on 100psi air pressure
for 10 days though so he & I were pretty confident there were no
leaks. The system has seven ball valves, seven unions, a silver
soldered copper manifold and about 20 other joints in it. Anybody got
a shop air system of this complexity that DOESN'T leak. All joints are
above the slab so repair was doable but not necessary.
Reply to
Leigh Knudson
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I am curious about hydronic radiant heat, and wonder if anybody here has experience using a lesser quality tubing than PEX.
Reply to
Jon Grimm
I was told by a plumber that PEX deteriorated relatively quickly (1 year?) in sunlight, and that that was why it was always installed underground or in concealed places, and also that that's why plumbing suppliers (in general) are not eager to accept returns on it if you've had it for any length of time - no telling how/where it has been stored. This is second hand info to me and I don't know if the amount of light in your shop would be significant, but you may want to do some research.
Reply to
Mickey Feldman
I won't get into judging better or worse, but I have installed, and am using a hydronic heating system in my shop, and have already installed a portion of an identical system in the new house we're building. The major difference is the type of tubing used. My system is a Heatway variety, a branch of Watts, who bought them out about three years ago. Heatway uses a proprietary rubber hose made specifically for hydronic heating, by a very well known American manufacturer. It has an oxygen barrier plus lamp black in its composition to improve heat transfer, and consists of three reinforced layers. It is available in various diameters, so pretty much any size installation can be addressed.
Like Leigh's report, my system holds beautifully. It has been in service for over three years heating our 2,600 foot shop and we've not had one drop of solution (clear water) leak. I'm sold on the system, and have no argument with the rubber hose they use. It is more expensive, although I do not claim it is either better or worse. My one and only worry with the PEX tubing would have been for an instance whereby the concrete floor cracked and shifted. I feel rubber would be slightly more forgiving of that scenario, but perhaps it wouldn't be. I installed 1/2" (#4) rebar @ 18" centers both ways, so even if it cracks, it shouldn't lose alignment, so in my case there is precious little about which to be concerned so far. The concrete has cracked only where it was scored, and there has been absolutely no settling of the 6-1/4" thick concrete.
I would suggest to you, or anyone that is interested in installing hydronic heating, that there be no experimenting with tubing. Only accepted materials with a good track record should be installed. Regardless of whether they are poured in concrete or stapled up, a leak could prove disastrous. I understand that the biggest problems they had with early systems was the inability to make water tight connections. That has been well addressed now and the systems, when installed properly, are very successful.
Hope this helps~
Reply to
Harold & Susan Vordos
Anybody got
I have in floor radiant heeting in my shop. All tubing and a lot of the fittings and such were purchased from
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The shop is 1080sq ft and I use a standard 40 gal 34K BTU hotwater heater as the heat source. It will maintain 55° F with outside temps at -15°. The only down side is having to keep it on all the time as it takes many days to come up to temp. My fuel is propane and it figures out to about $35 a month to keep heated during peak cold months. Bottom line, I really like it and would use this type of system in the future if I ever build again. I have 700 feet of tubing in the floor and no leaks so far. The systems is four years old now.
As far as air lines, my shop is located 150 feet from my house. My air compressor is located in the basement of my house. I did this for a number of reasons, but the key reason is much dryer air then out in the shop to start with. In the winter the basement is heated and central air keeps it dry in the summer months. I have a 3/4" black poly pipe buried four feet deep running from the basement out to the shop. In the shop I have the regulator that takes the pressure from 125 psi max to 80 psi. The entire shop is plumbed with the same 3/4" black poly-pipe. The poly-pipe is the same type used for lawn sprinkler systems except it is rated at 220psi @ 70°F I believe its call Gold-Line. My system has over four years on it and has worked great. I have mosture traps installed in the shop, however, I have no moisture in the air or the traps. The hose from the house to the shop works like a chiller, I think. It's cheep and will not shatter like PCV. I purchased a 300 foot roll from Lowes for around $23.
Eric D
Reply to
Eric D
My cats enjoy the radiant heat in the bathroom floor. It's been in for about 12 years or so and no leaks so far. It's 3/4" Wirsbo PePex cross-linked polyethylene I bought from a local Danex distributor. Danex marketed an aluminum radiant baseboard panel, it worked nicely but had to be wrapped around practically every wall since it did not put out the same BTU's per foot as conventional baseboard.
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