Sources for insulated pipe.

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Prices must be going down. I just paid $11 and change per foot of 1" Thermopex
 
ken999 said:
What are my options for 1 1/4" or 1 1/2" insulated pipe for an OWB? I see Central Boiler has 1 1/4" ThermoPEX. Are there others?

For 1 to 1 1/4" pex insulation you can bury in the ground look this over. Inside 6" (you would have to add on) a six inch tube or as the ad says "bury direct". 100' of non perf corrugated plastic tube at menards is $100. You can certainly build cheaper than buy pre constructed. http://www.ebay.com/itm/360066868785?ssPageName=STRK:MEWAX:IT&_trksid=p3984.m1423.l2649
 
Cave,
That stuff looks to be "open cell". Do they really know what they're doing when they suggest putting that product under ground?
 
WoodChoppa... They say it's expanded poly-styrene (closed cell?) but only comes in boxes (4' x 10 pairs of halves) 40' lengths. They say you can bury it direct but do not elaborate on what to do with the joints and the side seams. I was thinking of putting it in a 6" non perf tube you can buy at M'nards. The six inch corrugated tube runs $100 for 100'. Shopping for pex-al-pex and using the tube and insulation you might be able to self assemble for as little as $8 per foot.
 
That stuff looks to be “open cellâ€. Do they really know what they’re doing when they suggest putting that product under ground?

Sure looks like beadboard to me. It's easy and very common to confuse the terms "expanded" and "extruded" polystyrene. Beadboard is usually white and you can see it was manufactured as small beads of plastic that were swollen up to size and then allowed to solidify. It's also porous. It will take on several times its own weight of water and lose much of its insulation value.

If you can keep it dry it can work fine for some applications but it is also subject to deforming and shrinking when subjected to heat. I've never done any controlled experiments with it but I would stay away from the 200F the ad mentions. It certainly is not stable to as high a temperature as the common urethanes and the closed-cell "extruded" polystyrene like dow styrofoam that is sometimes called "blueboard" and others.

At one time someone posted some pictures of different types of foam that they boiled and you could see one of them was not pleased at the treatment it had received. Anyone have a link to that post?
 
Anyone know if the tubing used in Thermopex is O2 barrier type?

My own experience with factory made underground pex products is that there is nothing better (for many reasons) than MicroFlex/Watts R-flex. It delivers very low heat loss numbers and is very easy to handle, relatively speaking. It also comes in an interesting size (32mm) which is in between normal 1" and 1-1/4" pex.
 
This is a link to the specs of the pipe I used in my latest install. http://www.pexflex.net/htm/outdoor_index.htm The loss of temperature is insignificant between the boiler and the heating unit. I've used other pipe and this one is far superior plus it's oxygen barrier'd.
 
This is a link to the specs of the pipe I used in my latest install. http://www.pexflex.net/htm/outdoor_index.htm The loss of temperature is insignificant between the boiler and the heating unit. I’ve used other pipe and this one is far superior plus it’s oxygen barrier’d.




I forgot to add...... This tubing is available in the CT, NH, VT and NY area
 
Back in 2003 when I built the house, I put my oil boiler outside in a "boiler shed" becuase I didn't want to hear the roar...and I have no basement. I bought the 1" hePEX and wrapped it in the rubbery pipe insulation you can buy, and pulled two lines through a 4" conduit. There is considerable loss through this pipe. It is still in my system now. Without a doubt, it will melt some snow in the winter time. Right next to it I have my microflex installed and am working on getting the piping switched over (including hooking up the addition, extending the primary loop, blah blah blah). BUt I'd strongly advise against 1" line in "hot dog" type insulation in conduit.

With the microflex, don't forget about the Jentro connectors on the ends, they aren't cheap. I paid $70 a pop for them...and needed 8. Holy cow! As if 23.00 a foot wasn't bad enough...

Also, around that conduit with the 1" hePEX lines, I placed extruded polystyrene. When I dug some of it up getting the microflex in....the insulation was really heavy...it was really wet. So if you count on an R-10 for 2" after it has been buried in the ground for a few years, I think you'll be bummed. Maybe if you live in the desert....but then you wouldn't need insulated pipe! Even the extruded polystyrene, when in the ground, seems to suck up a good deal of water.....YMMV.
 
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