Dual 1" pex lines

[MrEd]

I know this has been discussed before, but can't remember if it got the blessing from the pro's or not.

I have an 90" roundtrip from the tarm to the oil boiler. Ideally I would use 1 1/4 copper, very expensive and tough to get locally without a 2 hour RT drive. Also, can't find any 1 1/4 pex tools to rent or buy at a reasonable cost.

Is running 2 side-by side 1" pex from 1 1/4 manifolds on each end going to cause me any real problems? I know its not as simple as calculating the volume because of the extra resistance, but does it matter that much?

Also, do the smooth bend/curves of a pex pipe offer less resistance than the 90 degree copper bends?

Has anyone already done this and had at least a few seasons to prove that it is a decent substitute for the one larger line?

 

[BrownianHeatingTech]

Two 1" lines have less flow resistance than a single 1 1/4" line.

Joe

 

[pybyr]

Joe/ other pros:

what's the best way to "terminate" any such dual or triple parallel group small-diameter line that's being used as a substitute for a single larger diameter line?

I'm assuming you want to keep the small diameter lines pretty close to exact same length, so that they flow equally,

and I'm also wondering what the best combination of fitttings is at the ends to join 'em all back togther with a minimum of (1) excessive/ avoidable head loss through the fittings; (2) cost of a lot of fittings; and (3) excess bulk or weird shape of the batch of fittings

thanks

 

[BrownianHeatingTech]

I'm assuming you want to keep the small diameter lines pretty close to exact same length, so that they flow equally,

The water will automatically equalize head loss, so flow differences won't matter. Head loss is going to be whatever the head loss of the worst (longest/most bent) run is.

and I'm also wondering what the best combination of fitttings is at the ends to join 'em all back togther with a minimum of (1) excessive/ avoidable head loss through the fittings; (2) cost of a lot of fittings; and (3) excess bulk or weird shape of the batch of fittings

A tee, cross, or manifold would be the way to go.

Realistically, there's rarely a reason to do such a thing - a single pipe will typically be cheaper than the equivalent in multiple pipes.

Joe

 

[MrEd]

Realistically, there’s rarely a reason to do such a thing - a single pipe will typically be cheaper than the equivalent in multiple pipes.

Theoretically yes, but if you don't own 1 1/4 pex tools, and can't locate 1 1/4 pipe locally, its not a simple choice.


But just so I am clear, all other things being equal (run lengths and pump size), using 2x 1" pipes should push more or less than same amount of heat as a single 1 1/4 pipe?

 

[BrownianHeatingTech]

Realistically, there’s rarely a reason to do such a thing - a single pipe will typically be cheaper than the equivalent in multiple pipes.

Theoretically yes, but if you don't own 1 1/4 pex tools, and can't locate 1 1/4 pipe locally, its not a simple choice.


But just so I am clear, all other things being equal (run lengths and pump size), using 2x 1" pipes should push more or less than same amount of heat as a single 1 1/4 pipe?

Two 1" pipes will flow more than one 1 1/4" pipe.

Joe

 

[pybyr]

Realistically, there’s rarely a reason to do such a thing - a single pipe will typically be cheaper than the equivalent in multiple pipes.

Theoretically yes, but if you don't own 1 1/4 pex tools, and can't locate 1 1/4 pipe locally, its not a simple choice.


But just so I am clear, all other things being equal (run lengths and pump size), using 2x 1" pipes should push more or less than same amount of heat as a single 1 1/4 pipe?

that's the same boat that I am in (I own a tool that will handle up to 1") and it also seems like the cost and complexities of the tools take a huge jump for sizes bigger than 1"-- to a degree that I couldn't even begin to think of justifying for the small # of times I'd need the really big sizes of PEX

 

[Tarmsolo60]

I have this setup on my gasifier (1" pipes paralleled, 2 for supply, 2 for return ) and it works fine. I bartered some labor for the pipe, had enough to do my house, sold 30' and still have a 27' piece left.
My neighbor is adding a gasifier and we are doing the same setup. you will have no problems.

 

[BrownianHeatingTech]

that's the same boat that I am in (I own a tool that will handle up to 1") and it also seems like the cost and complexities of the tools take a huge jump for sizes bigger than 1"-- to a degree that I couldn't even begin to think of justifying for the small # of times I'd need the really big sizes of PEX

That's what compression fittings are for.

I don't have a tool that will go over 1", either. Just not worth the investment, compared to the cost of compression fittings. I suppose if someone called me to do district heating for a major condo project or a whole subdivision, I'd spend for one of those, but for normal use, it's just not worth it, even for most contractors.

Joe

 

[MrEd]

So I can use any-old compression fitting? or does it specifically need to be made for pex or even the specific type of pex I buy?

I've checked pexsupply, they don't carry anything like that, that I could find. (They suggested I borrow a tool).

Can you provide a link to a fitting that would work?

 

[pybyr]

that's the same boat that I am in (I own a tool that will handle up to 1") and it also seems like the cost and complexities of the tools take a huge jump for sizes bigger than 1"-- to a degree that I couldn't even begin to think of justifying for the small # of times I'd need the really big sizes of PEX

That's what compression fittings are for.

I don't have a tool that will go over 1", either. Just not worth the investment, compared to the cost of compression fittings. I suppose if someone called me to do district heating for a major condo project or a whole subdivision, I'd spend for one of those, but for normal use, it's just not worth it, even for most contractors.

Joe

Joe- please tell us which type of fittings are quality and reliable without being overpriced; I'd looked briefly at some a while back and just about fell over at the cost.

If you've settled on something, I know you've done your homework on quality and value

 

[BrownianHeatingTech]

The fittings are specific for pex. They are not specific to brand, but you need to be sure of the size you are getting, since the actual ID of some brands differs from the listed "size" of the pex (so fittings listed for 1" for brand A might not fit 1" brand B pex, but might fit 32mm brand B, for example).

As far as brands/types of fittings, it depends upon the application.

For unpressurized or low-pressure systems, a barb adapter and some hose clamps may be all that you need. That's popular with the outdoor wood boiler folks, and it certainly does work, at a very low price.

As far as larger fittings, I'm trying out MicroFlex insulated pex on a job right now. I'm really liking the "Jentro" fittings that they supply. Pricey suckers, though. But for the convenience of a clamp-on fitting and the cost savings in not needing to purchase and maintain an electric or hydraulic pex expander, they end up being a good value.

I'm liking the MicroFlex pipe, too, by the way. Not cheap, but the specs show a lot less head than is typical of other pex, so we can supposedly downsize at least one pipe size, depending upon the specifics of the job. I'm going to take some measurements on this job, and see if that's correct, but I would presume that it is. The jacket is smooth on the inside and corrugated on the outside (sealed air space within the ridges), and seems pretty close to bulletproof. Insulation is foamed pex. Some of the nicest stuff I've handled.

I'm not a retailer, but I'd presume that retail prices would be in the $20-25 per foot for the 32mm duo pipe that we're using on this job, based upon the wholesale price. The fittings I would expect to retail in the $80-90 each range. When you're spending the kind of money that insulated pex costs, a few hundred for fittings and dust caps becomes small peanuts. Especially when you start adding up the costs to do multiple runs of smaller pex, both for the pipe itself, and for all those fittings at each end - I daresay if you add up eight 1" fittings, eight iron 90's, eight short nipples, and four tees, you'll probably be close to that, anyway, without even figuring the added cost of the extra pex.

Joe

 

[Tony H]

you could check with Cozyheat / one of the banners ads.I think they stock fittings and pex.