Taco iSeries 4-way Mixing Valve Piping

Brad White_9

that a short distance between the tees and valves (on the branches I am assuming here) will have a higher pressure drop in combination than if the valves are a few diameters away. The vena contracta or funneling effect as the flow enters the branch around that "hard corner" would benefit from some straight run. Academic really, you probably could not measure it, so it is just a principle. Fit for looks if you like, just that I would not rely on saving pressure drop as a reason. And if the pressure drop is in the branches anyway, that will not affect your main flow. It becomes part of your secondary circulator resistance. Again, this is if I am picturing and understanding your situation correctly.

Now, for fittings, rather than closelyspacedtees, I would use a copper EZ Header, Earthlee Speed Header or similar piece. Less space between and no nipple to ream out.

Still the 1-1/4 to 3/4" main-branch ratio bodes well for minimal pressure drop between the ports.

If you do go with copper tees and fittings just do the due diligence and ream those suckers neatly. And keep about five to seven diameters of straight pipe, more if you can, upstream and downstream of the branches.

My $0.02

Brad

Tom Nepsee

iSeries 4-way Mixing Valve Installations

Hello All,
I plan to install Taco iSeries 4-way Mixing Valves with 3/4" NPT ports in a hydronic system using a series primary loop with close-spaced copper tees. The tees are 1-1/4x1-1/4x3/4, and will be spaced no more than 4" apart. I want to provide for future servicing by making the valves easy to remove (probably using unions). I also want to make the connections between the valves and the tees as short as possible for neatness and to avoid excess hydraulic resistance. Can anyone offer any recommendations or examples of "best practices" as to what fittings, etc. would best accomplish this? Thanks.

Jed_2

Or

> that a short distance between the tees and valves

> (on the branches I am assuming here) will have a

> higher pressure drop in combination than if the

> valves are a few diameters away. The vena

> contracta or funneling effect as the flow enters

> the branch around that "hard corner" would

> benefit from some straight run. Academic really,

> you probably could not measure it, so it is just

> a principle. Fit for looks if you like, just that

> I would not rely on saving pressure drop as a

> reason. And if the pressure drop is in the

> branches anyway, that will not affect your main

> flow. It becomes part of your secondary

> circulator resistance. Again, this is if I am

> picturing and understanding your situation

> correctly.

>

> Now, for fittings, rather than

> closelyspacedtees, I would use a copper EZ

> Header, Earthlee Speed Header or similar piece.

> Less space between and no nipple to ream out.

> Still the 1-1/4 to 3/4" main-branch ratio bodes

> well for minimal pressure drop between the

> ports.

>

> If you do go with copper tees and

> fittings just do the due diligence and ream those

> suckers neatly. And keep about five to seven

> diameters of straight pipe, more if you can,

> upstream and downstream of the branches.

>

> My

> $0.02

>

> Brad

Jed_2

Or

You could use Taco's "Twin Tee", designed specifically for that application. They are available IPS or Copper connections. Hydraulic isolation is designed into them.

Jed

Ragu_5

I Learned 2 Things

The first is to pipe the secondaries off of the LEFT side of the primary loop; that way all the important stuff on the mixing valves is accessible, and you don't have to do any weird offsets to get get your 4 connections correct.

The other thing I learned is to DEFINITELY CONSIDER using a brass primary/secondary piping tee (such as as a Webstone) which has a ball valve on the primary between the 2 branches of the tee. Otherwise, they are a KILLER to purge.

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Jed_2

Ragu

Good point. Purging is sometimes a nightmare from what I hear. But, what if you have a shut off at the boiler in the Primary loop, purge station on the return of the secondary, won't the FF force the purge through the supply of the P/S tee through to the purge? And, sequentially purge all series P/S loops? Just asking to understand how it could be done. Webstone has some great specialties, haven't seen that one.

Jed