mono flow spacing formula

allenh

I am trying to correct a second floor loop which someone before me did. My questions are:

is it better to place the monoflow on feed or return side of the loop for the heater?

if I have a main loop with 3/4 and add a monoflow which reduces it to half inch - what should be a rough distance between mono and regular T? Right now there is a 10 foot 1/2 inch line to and from each heater which is buried in the walls.

Attached are 2 very rough drawings. One is a cross view of the building. It shows a 3/4 riser & then the loop in the cold attic. I am obviously eliminating the series stuff as there is no heat left in the last heaters due to reductions of half inch. The second attachment is the blueprint. The hot water hits bathroom first (nice and warm), and the largest bedroom at the end.

TIA.

Allen

Jack, CVMS

Monoflow spacing

You really should order Dan's book "How Come?" It would answer this question and many more.
Now to attempt to come up with a brief answer to your question: A monoflow tee (diverter tee) is most effective on the return side of the branch circuit. There, it not only provides a resistance to flow in the main piping, but there is also the advantage of a slight venturi effect to aid in pulling fluid from the branch circuit.
If your radiation is going to be below the main, then a diverter tee at both supply and return is necessary to overcome convection and insure initial flow. The diverter tees are to be the same distance apart as the length of your radiation.
Your next question mentions the monoflo tee reducing the branch piping to 1/2" - at least that's what I'm reading. Are you sure you have monoflo (diverter) tees, or are they just simple reducing tees? Does the main run - the one bypassing the branch supply and return - continue as 3/4"? If your loop piping is 3/4" and your branch runs are 1/2", you'll probably need to use a diverter tee at both supply and return to overcome the branch circuit resistance.

allenh

Just ordered the book. I always want to learn more. Thanks for the hint!

Yes the branches are below the main run which is 3/4. The branches are reduced to 1/2 inch and are about a 10 foot run on each side. So being that they are down I will add a mono on feed and return side.

One branch is to side about 10 feet. I kinda understand that I need one mono on return side. Now I am wondering if I need one on feed side.

The last heater at the end of the loop I might just run everything in series to that one. Its the largest room and the end of the loop. And its MY bedroom.

allenh

Just ordered the book. I always want to learn more. Thanks for the hint!

Yes the 4 of the 5 branches are below the main run which is 3/4. The branches are reduced to 1/2 inch and are about a 10 foot run on each side. So being that they are down I will add a mono on feed and return side.

One branch is to side about 10 feet. I kinda understand that I need one mono on return side. Now I am wondering if I need one on feed side.

The last heater at the end of the loop I might just run everything in series to that one. Its the largest room and the end of the loop. And its MY bedroom.

allenh

Just ordered the book. I always want to learn more. Thanks for the hint!

The branch is located in an attic in the third floor. It is a cold attic and if we have a power outage - it gonna be bad news. Yes, 4 of the 5 branches are below the main run which is 3/4. The branches are reduced to 1/2 inch and are about a 10 foot run on each side. So being that they are down I will add a mono on feed and return side.

One branch is to side about 10 feet. I kinda understand that I need one mono on return side. Now I am wondering if I need one on feed side.

The last heater at the end of the loop I might just run everything in series to that one. Its the largest room and the end of the loop. And its MY bedroom.