Another Plea for help with Underground Piping

Finally looks like I will have a window for installing the undergroung piping between my pole barn and house so I can tie my Scrapper, jr rebuilt efm 520 into my oil boiler. Only been waiting about 3 years to do this and now the wife wants to use a pellet boiler or "solar panels" instead of coal. Next she will be serving tofu for dinner.

Anyways, I have a backhoe on tap. I'm going to go down about 3 feet for an approximately 85 foot run. I was thinking of using 1 1/4 " black iron but found some 1 1/4 " pex-al-pex (ASTM F1281) for about the same price (not counting fittings, of course). I am actually thinking of doing two runs (4 pipes), a chase for electric and possible a potable water run. Tie them all together in a bundle with the chase in the center using cable ties every yeard or so. The line will be blocked so it is suspended about 2 inches above the trench floor and foamed (close cell) in the trench. There will be a minimum of 2 inches of foam around the pipe bundle. The guy doing the foam said I really don't have to bother lining the trench. Says he usually just puts a sheet of plastice on top of the foam to deflect water.

I guess I am a little concerned about the pex. I think I read something here about some cheap chinese product out on ebay--I'm not planning to go to ebay but the product from Outdoor Furnace Supply is called PEXworx and I have never hear anything about it nor can I find any info on the manufacturer. I can drop down in size and get 1 " Wilbro pex-al-pex from Pexsupply. I haven't found any other 1 1/4 pex-al-pex. So, am I getting hung up on this or should I go with the 1" which at least has some name recognition?

How did you determine the required pipe diameter?

katman wrote:I guess I am a little concerned about the pex. I think I read something here about some cheap chinese product out on ebay--I'm not planning to go to ebay but the product from Outdoor Furnace Supply is called PEXworx and I have never hear anything about it nor can I find any info on the manufacturer. I can drop down in size and get 1 " Wilbro pex-al-pex from Pexsupply. I haven't found any other 1 1/4 pex-al-pex. So, am I getting hung up on this or should I go with the 1" which at least has some name recognition?

Outdoor Furnace Supply is alternativeheat @ ebay w/ the same pexWorx 1 1/4". There is also another seller of similar @ ebay...honestystillives. I'm just saying, ebay or not you may be getting the same product.

I do not know why you would need 1" 1/4 for only 85' Our you feeding another boiler with a domestic coil in it? The 1'' with the right pump should work fine for a 85' length not to mention you can purchase 1'' at almost any local heating supply house ,fittings and crimps our much more common also.. I due agree with running extra lines I wish I would have ran one additional 1'' for a spare.. I did run a 3/4water line that never is cold in the winter wrapped with my heat lines.

Mac

I will be doing the same next summer.I can't make up my mind or make a good decision upon using black iron or copper( no pex,i afraid of a melt down),the price difference has alot to do with it,but i will be only doing it ONCE. Approx. 3-4' deep,total run 130',underdriveway,approx. 6-8" thick around with closed cell foam,additional buried lines for elec. conduit and a modine heater. I need 160-170 k btu.with my heat calculations, i belive that i need 1 1/4" or 1 1/2" pipes.My boiler has the capacity, it's 225k btu. Like i said i will be doing this project next summer so i will be following along with this thread to learn what i will be needing or what i have overlooked. Thanks Dennis

McGeiver, pretty much what I'm thinking about the seller. Spoke to them a few minutes ago to find out a little more about the product. Very little info. It appears they are basically a web site. BTW, thanks for the guage!

Mac, I figured the fresh water would never be cold. I have a refrigerator out in the pole barn. I just figured I would put the supply line in while I am trenching. The trench is going to go through an area with in-ground irrigation pipes and one zone control box, FIOS lines, and some other cabeling. I'm sure as careful as I intend to be, I'll have to do some repairs. Don't want to leave the line out and wish I had put it in. You do have a good point about the local availability of the 1 inch pex and fittings. However, most of the local suppliers seem to have "barrier" pex in stock, not the pex-al-pex. If I understand correctly, the pex with the Ox barrier is coated, while the pex-al-pex is an actual layer of al laminate. Please correct me if I am misunderstanding.

Dennis, I roughly figured my current requirement would be about a third less than your estimate, thus the desire to have a little excess. I had't checked material costs for more than a year so I was surprised to see black iron 1 1/4 at the local big box for about $2.20/ft while the web retailer noted above is showing 300 ft rolls of pex-al-pex 1 1/4 for about $675. I am a little leery about underground pipe joints, so the continuous run of pex is real attractive to me. That would probably still be the case if I step down to 1" in pex-al-pex. Unless I am missing something here, If I went to a non-al "barrier" pex the costs really seem to favor pex.

katman,
I also don't want any underground joints or couplings. I was pricing out 100' coils of k copper.I will have a 30 ' run buried under my basement floor and deciding to have the only joint inside,just incase a joint would happen to leak????It's looking at least $2500.00 just in copper.My boiler makes excessive heat and i dont want a meltdown with pex. My shop needs to be heated at 65 to 70 degrees. Dennis

macdabs wrote:The 1'' with the right pump should work fine for a 85' length not to mention you can purchase 1'' at almost any local heating supply house ,fittings and crimps our much more common also..

I would be hesitant to recommend a pipe or pump size without knowing what the load is. You can shove about 7 gallons per minute through 1" pex with a big pump, and that may or may not meet his needs. It wouldn't do the job at my house, and even if it would...I would prefer larger pipe and a smaller pump. You buy the pipe once and the electricity every month.

Threaded pipe is tough stuff...if you want to use it, pressure test the lines before backfilling the trench.

rob,
I was concidering black iron pipe,but would i get any rusting during summer while the boiler is not heating the shop. Also would 1 1/2" be suffient for 160-170k btu. anything else am i missing. I'm just getting started to plan this project. Dennis

My recommendataions is to use pre-insulated pex with the oxygen barrier. Won't be pex-al-pex but as long as the O2 barrier is protected you should be ok.

Underground piping is a pain in the a$$ to get it right and not have leakage, corrosion or heat loss problems.

Pre-insulated pex solves that problem. Upnor (wirsbro) is good for 200 deg F. working temp. It will probably be ok if hit short term higher temp but if you go higher than 200 deg. normal, you are way too hot.

http://www.uponor.ca/~/media/Files/Prod ... sc_lang=en

Pre-insulated is a little pricey but saves labor and problems, and can be ordered to length. Available up to 2".

High among all of the other considerations is the necessity to not have any ground water get into your pipe insulation. Wet insulation is no insulation. I'd run whatever you decide to use inside schedule 40 pvc with glued joints and terminations well above ground. Minimal extra cost but well worth it.

steamup,
the uponor is defenitly better product at 200 degrees along with being much easier to install and insulation factors as well along without having to worry about leaking joints.I was looking and couldn't find at place to purchase the uponor pipes, do you have any suggestions where to purchase the uponor pipes.Does the pipes have the oxygen barrier needed. Dennis

I would use iron pipe in a chase constructed of PVC pipe. Insulate the pipe with closed cell insulation purchase from a HVAC distributor. If you need to use a 45 or 90 in your chase, cut the elbow clam shell style install and pressure test your pipes, the glue (RTV Silicone) the top half of the elbow back together. I used 8" PVC well casing for my chase. Also added two PVC electrical conduits.

Thanks all for your comments and suggestions. I'm still scrubbing the numbers and talking to some suppliers. Also waiting to hear from my wayward plumber friend to see whether his material pricing can tip the scales toward iron pipe or any other option.

I did consider the uponor/thermopex and similar product options. Haven't ruled them out but they don't rise to the top of the list based on cost and pipe size options. I may be forced into one of these premade options if this cold weather settles in for the next couple of weeks and I decide to just do a temporary install for this winter. I'll be on-call again soon and then on the road, and I would like to get the house off of oil/propane. If I want to do in the trench closed cell spray foam my local guy wants it to be in the mid-40s. I don't want to dig the trench and set up the pipe for him unless I know we have the temperature.

Good to hear from Yanche and Terry, who live up the road a ways and have been generous with advice over the past few years. I gather neither of you are comfortable with the idea of spraying the pipes in the trench with no external casing? The spray foam guy says he does it all the time. Yanche, I did buy and read Siegenthaler's "Modern Hydronic Heating" and used the software for my heat loss, so as much as I hate crunching mumbers I'm trying to apply a little discipline. I know Rob-R is right about being able to push water through 1 inch pipe with the right pump, but unless the costs are prohibitive, I can't see what the downside is to using larger pipes to feed the house distribution system from the boiler in the barn. Is there a downside to having more volume in reserve than is called for by the immediate needs?

Anyone disagree that barrier pex would be adequate if protected? Seems this is what is used in most of the premade (uponor/thermapex) lines. Certainly much more readily available in various sizes than pex-al-pex.