Purchasing pex today, 1" or 1 1/4" ?

[trehugr]

Purchasing o2 barrier pex today for 85' run, 4' deep foam in ditch. Will 1" be good or should I go with 1 1/4" ?

 

[Eric Johnson]

I think 1" would be fine for a 25kw boiler. The nice thing about 1" vs 1.25" is that the fittings, valves, etc. are all a lot cheaper. And so is the pipe, for that matter.

 

[deerefanatic]

What you need is all dependent on flow... 1" is good for 8 gpm (80,000 btu) where as 1.25" is good for about 12gpm...... Using these numbers as a max is good design practice... Sure you can push more water through with a bigger pump, but that gets pricey real quick in pump and electric costs.... Or you can do what I did and run multiple sets of smaller pipe together.......

 

[trehugr]

OK, then what about this deerfanatic. Pexsupply.com has 300' of 1" hePex for 429.95 and 500' of 3/4" hePex for 429.95 The 500' would be enough for 4 lengths. Should I go with the 3/4" ?

 

[deerefanatic]

Well, first of all, I'd save some money and use the ThermaPex..... That's what I used and they are quite popular in Europe (Also made in Sweden, just like Wirsboro)

Second, I'd say go with the 1" stuff..... I know it's more, but 1" is definitely better.. Really, 1.25" is better than two 1" units, but then they get really spendy.. but for the price difference, I'd run single 1" vs 3/4"..... Now, if you intend to split your line up for multiple zones later on, then running multiple runs can be useful...... Both now and then........

 

[MrEd]

Maybe a dumb question, but is it safe to assume that any oxygen barrier pex that one purchases to use in a heating system would be safe to use for potable water?

 

[trehugr]

Yes, it is safe, but way more expensive.

 

[trehugr]

Just orderd 300' 1" ThermaPex....glad thats done

 

[deerefanatic]

yah, It's safe...... But spendy to use O2 barrier pex for potable... Now me, I had some short pieces left over, so I'm using it for hooking up my hot water indirect heaters and stuff.... But to say....... plumb a house, I'd buy the potable pex cause it's cheaper if you're gonna need alot......

I was completely happy with the ThermaPex's handling... Can't say anything about it's longevity yet as mine hasn't even seen water yet!