whats the max run for fin tube base board?

brain1023

i have a 25'x 55' slabbed house with a 4 year old wells McClain 100mbh 115,000btu. oil fired, fin tube baseboard, the two rooms furthest away from the boiler are the coldest, yet they are the first rooms on the loop,  1" main  down the center of the attic all the way to the opposite end of the house. drops into a  wall then a T into the twp problem rooms. from the T its 3/4 pipe which then there is two separate returns to the boiler.  the circulator is a 070 taco. i was suggested to remove the T and make one really large loop, this seemed wrong to me. would it be better and more efficient to put  another circulator and thermostat in and remove the T and make two separate loops?  One return now runs the front of the house and the second return runs the back. would this conflict with my idea? if so can i run two new pex 3/4" lines down the attic to replace the 1 " copper? Please help. thanks 

bill nye_3

Attic ?

 The 1" pipe runs the length of the house through the attic ? Is the attic insulated ? Is the pipe running through the attic insulated ?

 How hot is the water when it leaves the boiler ? and what are the return temps on your loops ? I would think this thing should work ?



 Changing it might make it worse.

icesailor

Fin Tube:

What you now have installed is correct. What you ask and propose is not.

Whomever designed the system needed a 1" supply and return and the amount of hot water it would carry. A 1" pipe carries more water than a 3/4". It takes 4 3/4" pipes to equal a 3" pipe. It takes 4-1" pipes to equal a 2" pipe. Because "pipes increase as do their squares".

If you want to improve your system, install a zone valve on each return where they come back together at the boiler. You will then have two zones with two thermostats. If one part of the house is colder than another, the zoning will resolve it.

The maximun run does not come into play in your situation because of the 1" supply and return.

icesailor

Fin Tube:

And I hope the pipe is insulated in the attic space. All the heat pipe should be  insulated. In the attic and in the basement/crawl space.

brain1023

max run

i should of put in my post. the return on the back loop of the house was in question to me someone piped a section of 10" in 1/2" i think this was done by and inexperianced homeowner. due to the pieces of pipe that showed that there was a prevoius break in the line. isnt this wrong. i figure it all should be 3/4" or it will restrict the flow. the amount of run doesnt seam excesive? i know the water temp out of the boiler is 175F one foot past circulator(push) the return lines ar 101 -104F six feet before re-entering the boiler.  Yes the line is very well insulated in the attic

icesailor

Fin Tube Restrictions:

The 1/2" pipe restriction will unbalance the loop. It is like adding a lot more baseboard on one side. The side with the restriction probably has a lower return water temperature in it. Feel the retturns where they come back together at the boiler. The side with the restriction is probably a lot cooler. Remove that piece. The water will take the path of least resistance.

What were they thinking?

brain1023

i dont think they were

i was thinking of taking out 10' of fintube baseboard and replacing it with a toe kick hydro unit would this be a bad idea? wanted to fix the restriction and  install the toe kick so i can put in a built in bench for the table in the kitchen. the baseboard i would like to remove is against a interior knee wall.

Ron Jr._3

Sure

We do that on Levitt style homes . Most of them on a baseboard loop of 80 feet or more . Just make sure to pipe in monoflow tees on the supply and return of the toe kick . Works very well .

brain1023

thanks

i was recommended to this site from fine home building break time. you guys are so helpful i have to admit im a carpenter by trade but plumber/ heating guy im not. thanks so much for the info 

Patchogue Phil_2

squares

It takes 4 3/4" pipes to equal a 3" pipe. It takes 4-1" pipes to equal a 2" pipe. Because "pipes increase as do their squares".





You might want to rethink your math.

brain1023

not fallowing you

sorry patch im not fallowing you, are you saying to remove the main and increase it, to be able to suport the two 3/4" lines?

Patchogue Phil_2

nope

No,  icesailor's math is off when finding equivalent volume of 3.0 inch and multiple 3/4 inch pipe.  I replied directly to his post.



IMHO,  sounds like the half-inch repair on the 3/4 inch pipe is causing a flow restriction and the low heat output.  I would change it back to 3/4 inch,  then see what happens and go from there if needed.

icesailor

max fin tube/areas:

4-3/4" pipes equal a 1 1/2" pipe.

4-1 1/2" pipes to equal a 3" pipe.

Math senility is moving in.

Patchogue Phil_2

common return

BTW,  are you certain which direction the hotter supply water is flowing?



I have seen a common one-inch  RETURN,  used by two  3/4-inch SUPPLY lines. 

icesailor

Typo's

The math wasn't wrong, the fingers were. I replied to your post here. It should have said that it takes 4-3/4" pipes to equal a 1 1/2" pipe.

Nick W

Poor insulation or air leaks?

In my very limited experience, most cold room problems are cause by inadequate insulation or air leaks rather than by heating system faults.

brain1023

not an airleak

i know what ur saying. not an air sealing problem. lack of wall isulation maybe some cause but it has a r13 ,new windows and new sealed house wrap threw out the house. it more than that thanks for the info.