Building a manifold - rules of thumb?

[MNBobcat]

Tonight I'm building my manifold using webstone purge tees. I was viewing a TACO video on hydronic systems and they mentioned that there should be at least 6 inches of spacing (pipe) between each tee. Are there any other requirements that I need to be aware of? Specifically, if I place a 90 on each end of the manifold does the 90 have to be a certain spacing from the first tee or doesn't it matter? I would deduce it doesn't matter but rather than make an assumption (mistake) I thought I would ask.

 

[twitch]

I'm not sure on the spacing, but instead of a 90 at the end, I'd put another 'T' and plug the end. This way it would be easier to add another zone in the future.

 

[Mid Michigan]

I watch some of the same videos. The video on high temp radiant heat said the closely places T's on the boiler loop should have 6" of pipe between them and the 90 at the end. Might want to watch that one.

 

[MrEd]

Defintely use a 'T' on the end w/plug like twitch recommend, so that down the road another set of pipes could be put in easily. Had the original installer (40 years ago) done that when my house was built, I would have saved many headaches plumbing up my boiler...it'll cost less than $10 extra, and you may never benefit from it, but chances are someone, someday will be really glad you did.

 

[hkobus]

When I setup my miximizer manifold, the following notes on "T" spacing came with the instructions:

Space between the "T"s is max 4 pipe diameters. Minimum 6 pipe diameters of straight pipe past and in front of the set of "T"s.

I'm sure there are other places to look this up, it has worked well for me sofar and I will use this in the rest of the system this week.

Henk.

 

[MNBobcat]

Thanks guys.

I'm space challenged on the wall where I'll be locating the manifold. I have an 80 gallon hot water heater crowding things. I was hoping not to have to have 6 inches between the 90s at each end and the first/last tees but according to what you guys are saying I'll need the 6 inches both between the tees and before/after.

 

[Gooserider]

If you are doing "closely spaced tees" you want the pairs of tees as close together as you can manage - prior post correctly stated that you want a maximum of 4 pipe diameters - less is better, use a "close nipple" on iron pipe, or when doing copper a section of pipe just long enough to have a barely visible copper ring between the tees before soldering.

You do want the 6 pipe diameter minimum between each PAIR of tees, and between a pair of tees and any elbows, valves, etc...

If you are "space challenged" you might want to consider the Taco "Twin Tees" instead of Webstone valves, as the Taco units put the two tee branches side by side, which reduces the amount of space needed for each pair.

The reason for the two rules is that you want to have as close to zero pressure drop as possible between the tees in a pair, so that you don't get pressure induced "ghost flow" when that circuit isn't running, so you want the two tees in a pair as close together as possible... You also want to avoid turbulence from one fitting disrupting the flows to the next fitting, and you want any water returning to the main line from a teed branch to have a chance to get thoroughly mixed before hitting the next pair of tees, which is the reason for the 6 pipe diameter minimum between pairs and / or other fittings. (Same rule applies to circs as well, you should have a straight pipe on each side, especially the intake...

Gooserider

 

[virvis]

Hey BobCat,

Can you post a link to the video. I'm trying to decide on building vs buying a manifold.

thanks,
Jim