Using the taco, "selecting circulator pdf" i have some ?s

[atvalaska]

thanks tenman ..here is the view taken out my living room window > just the evening before the triple pane window install...in fact, all the windows on that -the SW "face of the house" have that view

 

[ewdudley]

Copy Bob/EW. Explains the low end of Taco's recommended 2-4 fps.

Once the system has been purged I don't see how any air bubbles would find their way into the boiler-to-house loop and therefore running a bigger pump just for the purpose of maintaining minimum 2 fps is a waste of electricity.

 

[atvalaska]

standing in the same room as above... and looking SE and this is what it looked like one late spring day ..u kinda have to hook the 2 pics together to get the gist as it is a "mtn range"....

 

[Tennman]

OMG! Resisting massive hijacking of your design thread. OMG!

Carry on.....

 

[Highroad281]

. I googled 1 1/2" pex to get an ID and gave up.

I know there are variations between manufacturers, but the CB thermo measures 42mm od,32mm I'd. Believe Logstor 1.25 is the same.

 

[atvalaska]

1¼" Wirsbo hePEX
id 1.054" >1.054in = 26.772mm
od 1.375" >1.375in = 34.925mm

1½" Wirsbo hePEX ............this solves that ! .....vs CB thermo measures 42mm od,32mm I'd...

id 1.244" >1.244in = 31.598mm

od 1.625" >1.625in = 41.275mm

 

[Tennman]

Q of 24kbtu with 20F deltaT requires 2.4 gpm
1 1/2" pex w/ 1.244" ID
Velocity is only .63 fps
Assuming 10 elbows, 12 tees, 4 ball valves and 100' boiler to house (200' round trip) = less than 1' head loss
At ~2.5 gpm and low head pretty small pump. See Figure 2 of TD10 - either 003 or 006. 006 gives greater margin.

If the deltaT or Q changes based on others advice it only takes a second to change values in the spreadsheet. I have no idea if a deltaT of 20 is correct for a radiant system. EW mentioned a dT of 70. If that's the case the gpm and velocity get even less. It's fun to crunch the numbers per the recommendations of the pros.

All the numbers seem very small to me, especially for Alaska. You must have an amazing tight home. And I won't bring up that view.

If Q ends up as 48kbtu, gpm goes up to 4.8, 1.3 fps. The 006 would still work... the 003 on the edge.

Goin' home to look at my Tennessee hills. Kinda like the little bumps in your picture.