Look what I made tonight.

[BHetrick10]

This is what I made tonight. This is for a friend of mine. Before the mixing valve we have a dump loop and HWB. after the mix valve is two zones, first and second floor heat (radiant in floor). There is only two 300 loops for each zone. The gaps between the pipes is where the pumps will be going. This is going to be set up as a primary secondary loop. Since I am zoning with valves and not pumps do I need close T's or does the distance not matter? I didnt solder the offset yet.

 

[TheMightyMoe]

Looking forward to seeing your progress.

 

[BHetrick10]

Can anyone help me on the Close T ordeal? I would like to finish this up today but want to make sure things are done right.

Everything else look ok?

 

[TheMightyMoe]

Wish I could help, I always put tees as close as possible, I don't what's correct per code...

I would need a full diagram to see how your system works / will be plumbed, I can't tell just by this picture.

 

[Bob Rohr]

Can anyone help me on the Close T ordeal? I would like to finish this up today but want to make sure things are done right.

Everything else look ok?

Yes you need to tie into closely spaced tees if in fact you are piping a Primary Secondary loop. The only way you can build a P/S is with close tee.

 

[BHetrick10]

I didnt think it would matter if I am zoning with valves and not circulators. Sorry for my ignorance. Could you please explain to me what the close T's actually do?

My primary loop will be running vertical on the right hand side.

 

[Bob Rohr]

I didnt think it would matter if I am zoning with valves and not circulators. Sorry for my ignorance. Could you please explain to me what the close T's actually do?

My primary loop will be running vertical on the right hand side.

Here is a link to a good read on mixing devices. Basically P/S prevents multiple pumps and piping circuits from conflicting with one another. It interfaces multiple piping paths to prevent ghost, or un-wanted flow, and assures every loop gets adequate flow, to do it's job.

http://www.caleffi.us/en_US/caleffi/Details/Magazines/pdf/idronics_7_us.pdf

 

[BHetrick10]

I read the first 20 pages and am starting to get discouraged. The only thing I seem to be seeing about the close T's is they are used to increase return boiler temp. I know they do something with helping keep flow the way it needs to be. What I dont understand is if I am using pumps and zone valves the flow can only go the way the zone valves let it. I am just trying to understand what they do.

Here is a drawing of how the system gets laid out.

 

[TheMightyMoe]

The closer the tees the more balanced the flow. I think your setup is fine, other then my next question. comfort-calc.net has some simple plumbing information.

http://comfort-calc.net/Piping/Boiler w-p-s straight pipe.JPG

Since you are using the same returns for your radiant heat (100-130*?) and the baseboards (180*?), will your returns be cool enough to keep the radiant floors from getting too hot? Even if you had a actuating mixing valve, if your returns are 160* from the baseboard, that is as low as it will go. My garage is plumbed so that the radiant returns goto the 4-way mixing valve directly.

Rest of my house is baseboard.

 

[BHetrick10]

To be honest that is something I didnt consider. Ooops... I think you are right on that one. This stuff is relatively new to me and I dont necessarily know what I am doing. I keep reading a trying to learn though.

I suspect I would be better off having the two loops from before the mixing valve be on there own return.

Your link wont open.

 

[BHetrick10]

Does it matter where the two returns meet up at. I guess looking back at it I should probably had two location of two close T's. Problem is I dont have the room.

Hows this look?

 

[TheMightyMoe]

I think there could be to be flow issues as well. For example when your BB turns on, whats to stop it from going from the return to the supply side of the pump?
The problem is your not tied directly to the primary loop, with your secondaries. A check valve might solve that, but it's not how I would do it.

http://www.comfort-calc.net/primary-secondary_piping_tutorial.html




You could also plumb the Dump/BB return after everything, which is probably the best way. 180* to dump/BB, steady 180* with return to radiant, and the dump/BB return goes straight back to boiler.


I'm not a professional by any means.

I'm also not a fan of manual mixing valves, I prefer thermostatic / actuating when possible. More control = better.

 

[BHetrick10]

That link was simple and helpful. Thank you for posting it.

Guess I better come up with more room somehow to mount all this up. Wish I could just somehow merge the two returns before the primary loop.

Not sure I understand the plumbing that you are describing after the drawing.

 

[TheMightyMoe]

The return from the baseboard/dump could come after the return for the radiant. This would give you more constant temperatures for the radiant supply. Which means easier control.

 

[BHetrick10]

Talked to a local heating guy today. He said just T the hot water return in after my mixing valve and before the primary loop and all will be fine.

I think I'll try it. It will save a lot of space and I also wont have to refigure a bunch of stuff.

 

[TheMightyMoe]

If you are referring to your last diagram, that's questionable to me! Diagram me so I learn too =) Tell me how it goes, hope I got you on the right path.