? on Pex fittings..

[patch53]

I want to run 1 1/4' Pex for my underground lines this year. Anyone know what the approximate inside diameter on 1 1/4" pex fittings is? Are you really only getting 1" flow rate because of the restriction of the fittings?

thx, Pat

 

[leeeallen]

yes- the approximate inside dia. is one inch on 1 1/4 OD

 

[juddspaintballs]

if you use 1.25" pex-al-pex, my understanding is that is a true 1.25" ID. 1.25" pex has a roughly 1" ID, whereas 1" pex would be smaller along the lines of 3/4". So by saying you really only get 1" flow rate through 1.25" pex, you are technically correct, though in common terminology, you're getting greater flow than 1" pex.

 

[patch53]

if you use 1.25" pex-al-pex, my understanding is that is a true 1.25" ID. 1.25" pex has a roughly 1" ID, whereas 1" pex would be smaller along the lines of 3/4". So by saying you really only get 1" flow rate through 1.25" pex, you are technically correct, though in common terminology, you're getting greater flow than 1" pex.

Thanks Judd, I would actually like to use the Pex aluminum, but I don't think it is available in 1.25". If it is, I haven't found it anywhere?

What about the fittings? Does a pex fitting for 1.25" pex also only have a 1" inside diameter?


thx, Pat

 

[juddspaintballs]

What about the fittings? Does a pex fitting for 1.25" pex also only have a 1" inside diameter?t

I would assume so. I haven't run across any 1.25" pex-al-pex yet, but I'm going to be using simple o2 barrier pex in 1.25" so I really wasn't looking for pex-al-pex.

 

[patch53]

Well, since I only have a short 40' run from my boiler outbuilding to my house, I think I may go with 1 1/2" HePex. I would like to have a full 1 1/4" piping from the boiler to the storage tank so I can send all them good BTU's as quickly and efficiently as possible . LOL

 

[taxidermist]

Well, since I only have a short 40' run from my boiler outbuilding to my house, I think I may go with 1 1/2" HePex. I would like to have a full 1 1/4" piping from the boiler to the storage tank so I can send all them good BTU's as quickly and efficiently as possible . LOL

GOOD call Pat, I was told to run 1" and now I kick myself for not going larger. Learn from our mistakes.

Rob

 

[Tennman]

I'm running a boiler with a 210kbtu/hr rating and 1 1/4 hePEX. Boiler run between boiler and HX is about 170-180' one way. I only have six (6) 1 1/4 PEX fittings and am using a Taco 0013. The HX lines step down so the six PEX fittings can't be a major pressure drop contributor in the whole scheme of things. Everywhere else I use 1 1/2 black iron for manifolds and plumbing in the boiler room. Focus on the insulation of the lines to minimize the temp loss. Looking at the temp losses from my AZEL sensors at the boiler and the HX has proven I'm getting the energy to the house when I burn good cured wood and sufficiently heat the dirt around my underground lines. I sized my pump and HX to deliver 170kbtu/hr since everyone here says the advertised capacity of the boiler is under ideal conditions. I think folks here will tell you 1 1/2" is ok but if you do the energy/flow calcs given your short run, its probably unnecessary.

 

[juddspaintballs]

It really matters how many btu/hr and how much delta T you're looking for. Just a quick calculation for 200,000 btu/hr, if you wanted a delta T of 20 degrees F, you'd have to use 2" PEX, but if you wanted a 30 degree F delta T, you could use 1.5" PEX, or for a 35 degree F delta T 1.25" PEX would be just about maxed out. Obviously, if you need more or less btu/hr or you want a very specific delta T, then those sizes would change.

Check this link out for determining the size pipe and pump(s) you need
(broken link removed to http://www.taco-hvac.com/uploads/FileLibrary/SelectingCirculators.pdf)

 

[patch53]

I just bought the Taco 0014 Δ T circulator to use as my primary circulator from the boiler to the 500 gallon storage tank. I want to be sure that I can let my boiler crank at full bore without it cycling on/off while charging the tank. The 0014 will vary its speed to keep a set Δ T between the return and supply water. I really think this type pump will be ideal for this application. The 0014 will move up to 30 GPM at low head. I have no idea how much flow I'll need to keep the boiler from cycling, but with the short run I have and a larger pipe diameter I'm confident the pump will be able to move the water fast enough to avoid cycling. Can't wait to try it next fall.

Pat