What size pex tubing ?

[huffdawg]

I am installing an eko 40 in a detached shop .
I need to install a buried supply and return to my existing lp boiler.
It is all plumbed with 1" copper before the manifolds.

The Eko,s supply and return are 2"
The pex tubing would run 65' from Eko to lp boiler

Would reducing it to 1" pex be a problem.

The main plumbing supplier in town here have not ever sold 1-1/4 pex tubing.

Cheers Huff

 

[Chris S]

You need 1 1/4" pipe great reference here http://www.burnham.com/PDF/htghelper.pdf
page 24 has the information you need, sorry, I don't know how to put up just that 1 page.
If you undersize your pipe, you'll fight to get the btus where you need them.

 

[flyingcow]

Pex will vary in I.D. Some are actually smaller than listed.

 

[Hunderliggur]

I used 1 1/4 PEX for 80 feet underground and approximately 70 feet of 1 1/4 copper for my boiler/storage loop per the recommendations of Mark at AHONA. He can supply 1 1/4 insulated (wrapped) dual pex. You can also find it with a web search. Shipping is not all that bad. Use 1 1/4 barbered to pipe thread fittings to tie the pex to the copper.

 

[leaddog]

You can also use double 1in pex and it is easier to work with and find fittings.
leaddog

 

[huffdawg]

what sort of fittings do you use at the ends if you are doubling up on the 1" pex lines are there y fittings.
I cant get 1-1/4 pex where I live and I dont want to pay $360 for a pex press tool .
Thanx huff

 

[huffdawg]

I have two heating contractors tell me I could use 1' pex to supply my house load.
The radiant load in my house is roughly 50,000 btu and the indirect dhw tk. says 109,000 btu. continous rating (2nd. hr)


there is a taco 007 1-1/4 circ p/p that came with the eko 40 and a run of 80 ' one way .

Can any one explain the math to me .

Thanx Huff

 

[Gooserider]

I have two heating contractors tell me I could use 1' pex to supply my house load.
The radiant load in my house is roughly 50,000 btu and the indirect dhw tk. says 109,000 btu. continous rating (2nd. hr)


there is a taco 007 1-1/4 circ p/p that came with the eko 40 and a run of 80 ' one way .

Can any one explain the math to me .

Thanx Huff

One could ask the heating contractors if they will guarantee that if the 1" PEX fails to deliver a satisfactory amount of heat with a reasonable pump, they will come back and dig it up, and replace it at no charge...

For the math, see the Taco pump picking paper that I link to in the "tidbits" sticky - note that you may come up with several "right" answers, but they will vary in the costs for parts, and especially in the "life-cycle costs" of operating the system. It is also worth noting that burying and insulating the lines will be the largest part of the job - there is very little downside problem w/ oversizing the lines, but no practical recovery if you undersize - moral of story is that if in doubt on line size go bigger...

Gooserider

 

[huffdawg]

Thanx GR . I just ordered 4- 100' rolls of 1" pex . I will use two supply and two return. AS per Lead Dogs post
I was thinking of laying these out in the ditch and then have the spray foam guy come insulate them.

now I am lookin for some sort of y fittings fot the end of these pex lines.

Huff.

 

[Hunderliggur]

I used 1 1/4 PEX with brass barbed fittings to connect PEX to copper. I needed a heat gun to soften the PEX to insert the fittings, then double stainless steel clamps on each fitting. You probably can use 1 1/4 pex with shipping and the brass fittings for less than double 1" PEX.

 

[huffdawg]

Ya Iooked on line and 1-1/4" hePEX plus - (100 ft. coil)
SKU: A1141250Brand: Wirsbo (Uponor) $289.95

I got the 1" oxypex for $120.00 for a 100' coil.

So I think it would be around the same price.

I would also have to pay for shipping and taxes .

thanx huff

 

[sdrobertson]

now I am lookin for some sort of y fittings fot the end of these pex lines.

Huff.

You can just use 1" fittings and go into a manifold leading to your larger pipe. This would basically be making your own "y" fitting using steel piping. Pex to 1" fitting to 90 degree elbow then to a "t" and then to larger pipe. At the "t" insert fitting and then 2nd run of pex.

 

[huffdawg]

I think they make y's in steel fittings . I was thinking about load end where it ties in with my existing lpg boiler system which is all 1" copper.
Good idea though, it will help with the copper end hook up

 

[Gooserider]

Don't know how much "real world" difference it makes, but theory says that if doing parallel lines, the hardware on each end should be as close to symmetrical as possible - i.e. do the home brew manifold, at each end, doing something like "pex-fitting-elbow-nipple-tee-nipple-elbow-fitting-pex" with both elbows going into the main trunk of the tee, and the other line going into the snout... Alternatively if you do an asymetric setup, make both ends the same way and swap which Pex line goes to which fitting... The key idea is that you want both lines to have as close to the exact same head resistance as is humanly possible...

Gooserider

 

[Hunderliggur]

Whis is one reason to use a single larger pipe. If you do the head calculations for each fitting (pex-pipe, 90, nipple, T, nipple, 90, pex-pipe) you will find a significant head loss compared to a single pex to pipe fitting. The loss going into the T is significant. You are going to be circulating through that higher head loss (on both ends) for years to come.

 

[mwk1000]

Another alternative if your on the edge is PEX-AL-PEX. In the table below the values are a multiplier for flow rate. You can see that in the larger PEX sizes 1" Pex-al-pex is going to move almost half again as much water as 1" pex (46% more ) . If it's not twice as expensive then it fits the need with fewer fittings and less cost. A quick check on pexsupply shows that it is not! Pex is 360$ for 300' Pex-AL-Pex is 435$ for 300`.

Table 1. Value of pipe size factor (C) for several types of smooth tubing
Tube (size & type) C value 3/8" type M copper 1.016
1/2" type M copper 0.3335
3/4" type M copper 0.06196
1" type M copper 0.01776
1.25" type M copper 0.006808
1.5" type M copper 0.0030668
2" type M copper 0.00083317
2.5" type M copper 0.0002977
3" type M copper 0.0001278
3/8" PEX (I.D. =0.36") 2.9336
1/2" PEX (I.D. = 0.475") 0.7862
5/8" PEX (I.D. = 0.584") 0.2947
3/4" PEX (I.D. = 0.670") 0.1535
1" PEX (I.D. = 0.86") 0.04688
3/8" PEX-AL-PEX (I.D. = 0.35") 3.354
1/2" PEX-AL-PEX (I.D. = 0.47") 0.8267
5/8" PEX-AL-PEX (I.D. = 0.63") 0.2056
3/4" PEX-AL-PEX (I.D. = 0.79") 0.07016
1" PEX-AL-PEX (I.D. = 0.98") 0.0252

 

[huffdawg]

Whis is one reason to use a single larger pipe. If you do the head calculations for each fitting (pex-pipe, 90, nipple, T, nipple, 90, pex-pipe) you will find a significant head loss compared to a single pex to pipe fitting. The loss going into the T is significant. You are going to be circulating through that higher head loss (on both ends) for years to come.

Cancelled the 1" pex and ordered 200' of 1-1/4 hePex from pexsupply .

 

[mwk1000]

Glad to hear it. That is the smart thing to do IMHO

 

[hkillam]

Just a cautionary note:

Make sure Pexsupply has the product in stock! I had to cancel an order with them when, two weeks after placing the order and having my card charged, I called and learned that they didn't have the item to ship. They'd failed to inform me, yet still charged my credit card. Not cool. This was also for 1 1/4 pex, though I forget what brand. I know they were having some challenges meeting demand for some items roughly 18 or 20 months ago. With any luck that is no longer the case. In fairness, they were quick to cancel the order and refund my money immediatly when I requested it.

 

[huffdawg]

Just a cautionary note:

Make sure Pexsupply has the product in stock! I had to cancel an order with them when, two weeks after placing the order and having my card charged, I called and learned that they didn't have the item to ship. They'd failed to inform me, yet still charged my credit card. Not cool. This was also for 1 1/4 pex, though I forget what brand. I know they were having some challenges meeting demand for some items roughly 18 or 20 months ago. With any luck that is no longer the case. In fairness, they were quick to cancel the order and refund my money immediatly when I requested it.

The chap @ pexsupply told me he would get it shipped out today. And would be in blaine Washington next Fri.
Hopefully he was being straight up.

 

[huffdawg]

I used 1 1/4 PEX for 80 feet underground and approximately 70 feet of 1 1/4 copper for my boiler/storage loop per the recommendations of Mark at AHONA. He can supply 1 1/4 insulated (wrapped) dual pex. You can also find it with a web search. Shipping is not all that bad. Use 1 1/4 barbered to pipe thread fittings to tie the pex to the copper.

I think I will try the barbed fittings as well. How long have they been on your system. No problems?

 

[Hydronics]

The frost must be a ways down right now especially in Canada. How are you planning to excavate the trench? Going with 1- 1 1/4" was a wise choice.

 

[huffdawg]

The frost must be a ways down right now especially in Canada. How are you planning to excavate the trench? Going with 1- 1 1/4" was a wise choice.

My trench is dug down 2' . I live on the west coast on Vancouver Island. it isnt all that cold here usually.

Last year it got to about 5 °F for about 10 days and thats very rare.

no frost right now . The average here for the winter months is about 37 °F

the building code here says you have to build your footings below 16" . I dont think I have ever seen the frost level here below 4"

Cheers huff.

 

[Hunderliggur]

Here in Anne Arundel County Maryland we have to go down 30 inches. In the county to the south (Calvert) it is 18 inches. It doesn't matter that my back property line is the county line and the frost line magicaly jumps 12 inches 200 feet south of my house!

About the barbed fittings on PEX. It has been running for 3 weeks with no leaks whatsoever. I pressure tested cold at 60 psi. System runs hot at 20 psi. I ordered the fittings from plumbingsupply.com Brass Barbed Male Adapter 1 1/4"x1 1/4"mips $18.67 each. The barbed fittings were recommended by AHONA and they have a lot of successful installs. I second the opinion on PEXSUPPLY. I have used them, they have great prices. Service and shipping is normally great. HOWEVER - I ordered my fittings for the boiler install in November. Their price was about 1/2 the local supply for 1 1/4 copper fittings. Many of the items were "backordered", including a Taco 0011. I eventually cancelled the balance of my order and got the parts locally. If you call and verify stock and shipping I thing you are OK.

 

[btuser]

Our frost level is 48" in Southen NH. I'm guessing that's about 2x what's needed.

The only reason I could see to keep the pipe size low is velocity, but that's more for industrial/commercial applications. I don't think you need to worry about 1 1/4. That will push 150k, at least that's how I sized my headers for my boiler. Less fittings, less places to break. Less parts is better than more parts.