Why Size Should Be My Main Pipe To Distribute To Baseboards

joseluisheating

I trying to create a high efficiency hydronic system for my second floor. My goal is to run water @ 140-150f with long fine tube baseboards. I'm trying to have a two zones with reverse return piping layout.

The house was built in 1928, second floor has not insulation and walls are lath and plaster.

I would attach a diagram below. Please any suggestion commented it.

I have couple of question:

Boiler would be on the basement but the apartment is on the second floor, should I make each zone-main (zone1, zone2) pass through first-floor ceiling or basement ceiling with parallel pipes to the baseboards ? If yes, how to deal with less resistance path ?

If each baseboard supply and return are 3/4" at 4gpm, what sizes should be each zone-main (zone 1, zone 2) ? Knowing that zone-1 has 5 baseboards and zone-2 has 3 . and what size should be the manifold of the two zones ?

Last question. Should I install a ball valve in the supply, and a balancing valve (set to 4gpm) in the return of each baseboard ? Like the picture below but instead of a zone valve a ball valve.

I attach the diagram guys and the picture. Hope to hear from you back

leonz

Buenos Dias Jose,

I think a top fed single pipe steam heating method with panel radiators or small tube type steam radiators would be simpler and would be much less work.

The single steam riser pipe would be placed directly over the boiler and rise to the second floor ceiling and then a tee would direct the dry steam to the left and right side of the second floor ceiling and then tee off the right side header pipe to the bathroom radiator. You have to make sure that you have the adequate number of air vents at the ends of the header pipes to allow the steam to rise quickly and heat the radiators quickly.

A steam radiator will provide you with more thermal mas to heat this building.

JohnNY

Fin tube baseboard convectors are the least good option when designing for high efficiency hydronics. Try to install something with some mass to it and you can drop your water temperature to far less temperatures than your current goal.

joseluisheating

@leonz gracias por su comentario,

Ya tengo steam instalado en mi casa. Pero el uso mensual me esta saliendo un poco costoso, las tuberias estan oxidadas, el sistema no esta balanceado, etc.

Quiero instalar una boila de agua caliente, con tuberia pex y baseboards. Quiero poner este tipo de systema porque aun que sea mas complicado, sera mas facil de maniobrar atravez de los anos.

I already have steam installed in my house. But the monthly use is getting a little expensive, the pipes are rusty, the system is not balanced, etc.
I want to install a hot water boiler, with pex pipe and baseboards. I want to put this type of system in place because even if it is more complicated, it will be easier to maneuver over the years.

hot_rod

zone 1 has 78' of fin tube? If that is rated at 550 btu/ft, 42,900 btu/ hr, then at a 20∆ you need 4.9 gpm.

Ideally a RR starts with the size tube to carry that 4.9 gpm and steps down as you go, so feed the first 18, fin with 1", step down to 3/4". The opposite on the return side. That is the very best way to pipe RR if equal pressure drop is the ultimate goal. Plus some pipe cost savings.

Notice all the RR drawings, fig 9-4, intend to show the pipe sizing by the size of the lines used in the drawing.

That 9-4 could be 1" starting out, reducing to 3/4" and even down to 1/2" for the last fin. Reversed on the blue, return lines.

I'm not sure you need both a ball and balance valve as you need to fit them into the enclosure somehow. it's rare to see either on small residential fin tube jobs.

Usually you can balance by just adjusting the dampers and get accurate enough.

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joseluisheating

@JohnNY thanks for your comment

Baseboard has very low thermal mass compare to others but it is the cheapest out of all. Long radiators are close to $1000, floor heating with pex and plates would be more expensive. 18" baseboard would result in like $250 and @ 150f, it can output 380-400 btus per foot. Therefore I choose Baseboards.

Do you know any good thermal distribution system that would be cheap but more efficient ?

joseluisheating

Thanks for your explanation @hot_rod

I'm trying to run water at 150°F, which results in an output of 380 BTUs. I need help with plumbing and sizing, specifically with my Baseboards. Each Baseboards requires 4 GPM, and I know that 1/2" PEX can carry a maximum of 2.3 GPM, while 3/4" PEX can carry up to 4.6 GPM. I'm not sure if 3/4" main can carry 4gpm to each baseboard, correct me if i'm wrong. Maybe with a pump can you guide me with that.

My question is: After the first 18", can a 3/4" main line carry 4 GPM to the remaining baseboards?

Also, could you explain how to achieve a 20°F delta T (temperature difference) I don't know to calculate that?

Additionally, could you provide a picture of a damper? When I search online, I only find images of duct pipes.

It would be much easier if the baseboard pipe were 1/2" so I could install a manifold. Unfortunately, there isn't a manifold available for 3/4" PEX.

leonz

Hola Jose,

Gracias por su explaca'cion,

How old is the steam boiler? Is the steam boiler sitting on blocks in a wet basement or on a dirt floor??

It sounds like your boilers burner just needs to be tuned up and the boiler needs to be cleaned and flushed out.

How old is the steam boiler?

How long has it been since the boiler has been serviced or the mud leg drained out and the boiler base been rodded out and flushed?

How long has it been since the pig tail for the pressuretrol was cleaned??

Your steam boiler will run more efficiently if it is cleaned and tuned up.

Does your steam boiler have an autofeed valve or a manual water feed valve? It is equipped with a low water cut off?

If your boiler water is dirty/cloudy it needs to be cleaned and flushed.

A steam boiler does not need to be replaced unless it is leaking on the floor.

Do you live near an architectural salvage yard where you could buy used cleaned and tested steam radiators?

joseluisheating

@leonz Thanks for your comment

There are many things with this system that wants me to get rid of it. Pipes are leaking, pipes are rusted, obstruct my basement ceiling, etc.

hot_rod

https://forum.heatinghelp.com/discussion/comment/1807611#Comment_1807611

The free PPI calculator will size the pex.

Caleffi manifolds will accept 3/8- 3/4 pex, and the inverted version can be helpful.

A homerun would be a good option

Do you get enough output at 150F for the room loads?

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https://plasticpipecalculator.com/PressureDropHeadLoss.aspx

joseluisheating

@hot_rod you are the best

It is now way easier. The manifold would balance the flow (gpm) for each baseboard loop.

Let me do the diagram again.

Water temp @ 150f of 18" baseboard line/2000 @ 4gpm each = 6,840 btus/hr

for an average of 140-180 sqft rooms. I use supply house baseboard calculator ? You think it is too little baseboard or it is enough ?

One more question:

What is a homerun ?

Why we need to know the pressure drop or head loss ? how important it is ?

Do I have to measure the length of each loop baseboard both (supply and return)

joseluisheating

55885_PROD_FILE.pdf