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[mlappin]

Another new member caught in the authentication boondoggle.

New guy here trying to get some plumbing ordered before my boiler gets here. I'm currently running an oil boiler with baseboard heat. I will be installing my wood boiler to run through a 50 plate HX at the oil boiler and then probably a 20 plate for the DHW. The boiler will be approximately 120ft from the house. I plan on running 1-1/4in lines all the way to the house. Also the oil boilerd return line  where the HX will be is 1-1/4in.
 
Should I stay with all 1-1/4in lines, valves, fittings ect. For everything inside?? It seems like this is the way to go, but at double the cost for fittings, etc. I just want to make sure it's the correct design. Or can I step down to 1in for what's inside? The oil boiler and DHW are within 10ft from the basement wall, so the inside run will be short.

[mlappin]

One inch pex is roughly the same ID as 1” copper or steel pipe. However if your running all pex in your basement by time you buy adapters to go from the 1 1/4 fittings to one inch valves etc then back up any savings might be nonexistent.

[RSI]

One inch pex is roughly the same ID as 1” copper or steel pipe. However if your running all pex in your basement by time you buy adapters to go from the 1 1/4 fittings to one inch valves etc then back up any savings might be nonexistent.

Did you mean 1-1/4" pex? 1" pex is smaller than 1" copper. I would not keep going back and forth with a lot of adapters. If there isn't that much pipe in the house then 1" is probably fine. Or you could just do it all with 1" copper and not have any reduction in size.

[tinfoilhat2020]

i woulg go with 1 inch copper if the run is short....no restriction and it will look purty

[tinfoilhat2020]

I was going to go with 1 1/4 when i just installed new lines but i ended up going with 1" for the simple fact that i have another 120ft of pex ran inside my house...i didnt feel like switching all that out

[ralphxj]

Not sure if I can reply or if the will need approval as well??

I should have worded my post better. Once I get the Pex into the house, I will be running all copper between the HXs and all the vavles and stuff until the return pex back to the boiler. Sounds like 1in copper lines and fittings will be good. That has the added benefit of being able to get stuff at Home Depot in a pinch which is only a mile for the house, rather then online!

[mlappin]

One inch pex is roughly the same ID as 1” copper or steel pipe. However if your running all pex in your basement by time you buy adapters to go from the 1 1/4 fittings to one inch valves etc then back up any savings might be nonexistent.

Did you mean 1-1/4" pex? 1" pex is smaller than 1" copper. I would not keep going back and forth with a lot of adapters. If there isn't that much pipe in the house then 1" is probably fine. Or you could just do it all with 1" copper and not have any reduction in size.

Yep, my bad, 1 1/4” pex has roughly same diameter as 1” copper. Copper will look purty like pointed out already and won’t require dozens of supports to keep it from sagging when it gets hot.

[mlappin]

A reply from the OP.


I should have worded my post better. Once I get the insulated pex into the house, I will be running all copper between the HXs and all the vavles and stuff until the return pex back to the boiler. So I would have a fitting that goes from the 1-1/4 pex to copper, and then would stay at the size copper until I get to the end of the inside run and then another fitting back to the insulated pex. Sounds like 1in copper lines and fittings will be good? Just wanted to be sure so I didnt restrict the flow too much. The cost of 1in stuff is less and the added benefit of being able to get repair parts at Home Depot in a pinch which is only a mile for the house, rather then online since no one carries 1-1/4 copper other then specialty stores with limited hours!

[mlappin]

Thats exactly what I did in my shop last winter, ran 1 1/4” pex then 1” copper where required.

[Sloppy_Snood]

For those who installed 1 1/4" but reduce to 1" inside the house:

Do you see any problems with flow restriction or inadequate BTU delivery to your heat exchangers in order to meet peak demand situations? 

[U.P. Doug]

I have had no issues with flow to my exchangers in my set up and I reduced to 1" copper once inside the house.

[willieG]

both 1.25 pex and 1 inch copper (type M) are very close to each other for friction loss. I doubt most folks would notice much difference with the pipe.  copper fitting (elbows tees and such) have less friction loss than pex but in most cases you will use less pex fittings so that likely comes out as a wash as well. ((I think a 90 in 1 inch copper is equal to about 2.5 feet of pipe and one in the pex would be between 10 and 18 feet of pipe depending on style of fitting))

[Sloppy_Snood]

Thanks U.P. Doug and willieG!

[mlappin]

both 1.25 pex and 1 inch copper (type M) are very close to each other for friction loss. I doubt most folks would notice much difference with the pipe.  copper fitting (elbows tees and such) have less friction loss than pex but in most cases you will use less pex fittings so that likely comes out as a wash as well. ((I think a 90 in 1 inch copper is equal to about 2.5 feet of pipe and one in the pex would be between 10 and 18 feet of pipe depending on style of fitting))

Copper long radius 90’s are a must, take up more room but flow much better

[juddspaintballs]

I went with the 1-1/4" equivalent Logstor in the ground.  I have reduced to 1" PEX in the house.  The reason I did 1-1/4" in the ground is for future expansion, including running heat to my detached garage.  For now, 1" in ground lines would have been plenty for me, but I wanted to never have to touch my ground lines again. 

I like idea of 1" copper in the house.  I may do that at some point when I rearrange my basement.  I've gotten pretty good at sweating copper now.  The only downside to doing all copper inside is that if you have a longer run in the house, you're going to leech heat into your basement or house at a much higher rate than PEX will unless you insulate it all.  Sometimes having the extra heat in your basement radiating from the pipes is a good thing, but sometimes it's not good for temperature control in the house either.