the need to install eccentric reducing couplings on a closed hot

Christian Egli_2

All this talk is nice, but then, how would we have our eccentric idea without first cutting out the offending reducer?

There must be a grander scheme to all this. Perhaps the new coupling which will raise the reduced pipe by a whole 1/4 inch will allow for sliding the tall furniture bellow the pipe. Who knows?

One bonus, though, if and whenever this system gets converted to steam, you'll already have your off center reductions in place. All you'll need to do is rotate them by half a turn. *** It couldn't be more convenient.

Pascal himself came up with a whole book of thoughts which he arranged in a philosophically concentric circular fashion... yeah... it makes no sense either.

Bob zeroing in on out of control school boards makes timely sense, though. Our local system, just now tonight, is plotting to go for a 16% property tax increase. It costs tons of money to do stupid things and they won't learn.

Off hand, I can't think of anything practical. Problems like this make me laugh and cry and the same time. Good luck.

edward j genario

use of eccentic couplings on a closed hot water heating system

dan

i have asked this question before on this site and didn't get what i thought i could present to an engineer on the project we are doing.
we are being asked to cut out a 3"x 21/2" welded concentric reducing coupling and replace it with a eccentric coupling on a closed hot water heating system that is tested and insulated and which has several reducing tees on the run which are the same as using concentric reducing couplings.we have asked why but get no real answer.
in your professional opinion is there a good reason for this request?

thank you
ed

Ken_40

Ed,

I cannot speak for Dan but can speak for common sense; at least on this one.

Eccentric reducing welded fittings or threaded are essential when applicable for steam; not water systems.

The Cv value of either fitting is virtually identical - whether concentric - or, eccentric.

Unless some exotic thermo-dynamic extremely "low flow" process application, where stratification dynamics are involved, there is no beneficial purpose to switching from concentric to eccentric fittings.

However, if this is a mistaken spec. specified by an egotistical "engineer" who refuses to acknowledge his/her mistakes, and that person has any say in your payment...

Brad White

Ed, I agree with Ken

The principal benefit to eccentric reducers are in steam systems. In hot water there is no real harm so long as they are run flat on top to keep air moving. Kind of expensive and hard to find too!

Realistically though, a concentric also has a "shoulder" but normal velocity will move the air right through.

Speaking from the engineering perspective, "if it ain't broke, dont' fix it". Does it work and does the balancing report verify performance?

If your engineer has a different take on it, I for one would love to hear it.

There may have been a specific reason such as having it shown on contract documents for whatever reason. Then you may have no choice or can negotiate a proper credit for the cost difference if any, plus an indemnification of performance.

Personally I cannot see how the performance would be harmed even if flat-on-bottom given that the shoulder dimension is not that extreme.

My $0.02

Brad

bob young

overboard spec.

Sounds exactly like a school construction over the top code exceeding spec. written by a engineer from pakistan who read a book. those guys are impossible to reason with. give 'em what they want & charge triple for the grief factor.