new monoflo install.

Tom_10

Just gutted a three bedroom cape on the Jersey shore. Used to have baseboard on all the walls. Needless to say I did not spare it during renovation. I had my local heating supplier do the heat load on all the rooms. They supplied me with the appropriate sized recessed radiators to accomodate each room. There is currently a 1" loop on a monoflo system with 1" x 3/4" monoflo tees to all the old baseboard. The 2nd floor has two six foot sections of Slant fin #30 and the tees for those are 1"x1/2" monoflo tees in the basement. They transition to 3/4" by way of 3/4"x1/2" copper 90s at the baseboard. My intention is to completely re-do the monoflo system to accomodate the new sun rads. I was going to use 1-1/4" loop with 1-1/4" x 3/4" monoflo tee on the "return" side of each rad. My questions are these 1) Is there a minimum or maximum distance that the tees should be apart? Can they be too far apart? 2) Do I need more than one diverter tee per radiator.(There will be no rads in the basement so no downfeed is involved) 3) Is 1-1/4" loop too big or too small. Is there such a thing as too big of a main? 4) Does it even have to be monoflo to supply the rads or is there another option?There will be a total of 5 rads on the first floor(between 10 and 18 sections each) The second floor will be a separate zone of baseboard as will a sun porch. I would like to pipe this ONCE and once only as I don't really need the practice with the torch. Any assistance from this group would be appreciated. Thanks in advance.
Tom

Steamhead

Tom, how much radiation

will be on the monoflo loop, and what capacities to those Sunrads have? When we know these things we'll know if the pipes can handle it.

Normally on upfeed monoflo, you only need one monoflo tee on the return line from each radiator. It's a good idea to space the tees as far apart as the length of the radiators they serve, though sometimes you can get by with less.

Be sure to Pump Away- if you don't, you'll be bleeding that system forever!

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[Deleted User]

And...

did you know you can make your own mono flow tees? The original B&G MonoFlo tees have one heck of a pressure drop to them if the branch is closed.

Nibco makes an insert that can be dropped into the run of a tee and converts the tee to a venturi tee. They make them all the way up to 1-1/4" sizes. Here's a picture of one that I made for my house that uses the Buderus panel radiators. The radiators have a 2" on center inlet/outlet, so I had to "modify" the conventional tees to make this work. I put a diverter in the inlet tee and a venturi on the outlet tee because I too have way too much experience soldering. It works like a champ.

I know they don't recommend putting divert and venturi tees this close together, but it IS my experiment, and I thought I'd try and overcome the laws of nature (once again) and I'm happy to say it (the system as a whole) works like a champ. I think it would work even better with some distance between the tees. As Frank said, if the radiators are above the main, a single divereter or venturi wil work. If its below the main you'll need to to overcome the tendencies of gravity and bouyancy, which will require a divert adn venturi.

Gotta be careful with the chop saw when taking the excess shoulders off of the tees though... You are pretty close to a fast, sharp moving blade.

Glad to see someone else adopting the "old way" of piping a system.

PS. As you are looking at the fitting, flow would be from left to right. The first insert is a "modified" 3/4" fitting X 1/2" reducing coupling. It has a "fatter" profile as it pertains to the lines of flow in a pipe. The insert fitting (cone) on the right is the Nibco venturi fitting. It's sleeker, but has a narrower outlet throat the causes the higher velocity necessary to cause the venturi effect.

ME

Tom_10

more monoflo

the load on the monoflo loop will amount to between 35,000 and 40,000 btu's. As I said earlier, there is a total of 5 rads on the entire loop with a total of 60 sects. PLUS, at some point when I rip out the bathroom on the first floor I may want to put a kickspace heater. I've been told that I should limit each loop to 5 rads/monoflo loop. Any truth to that? Can I have too much on the loop to the point where it will not work properly? I think that the bottom line is that I dont know how to calculate my pipe sizes with regard to pressure drop, system load ect. ect. My main concern is undersized or oversized pipe and the possibility of doing things twice( which I REALLY want to avoid) Mark, I know the fittings of which you speak. Thats some effort there with regard to your"invention". I know those fittings as "drop in" bushings and have used them in different applications than yours. Neat idea though. I will consider your option but am really not willing to experiment on stuff that will be underneath new sheetrock soon. As always I will pump away, along with a spirovent,pressure reducer in the proper location ect. The boiler part I can do with my eyes closed, sort of, well, maybe one eye anyway. Don't want to get too cocky here. Its the system part that has me in a knot. Also, do I need anything with regard to my transition from copper main to iron rads? Thanks you guys, keep the ideas coming to me so I can get this "ironed" out. Tom

[Deleted User]

One pipe limitations...

Remember, the main is parallel to the loads. Pressure drop is relatively insignificant. What is critical is temperature drop. The radiators on the front of the system will be seeing much hotter water than will the back end, so you need to account for that by installling small rads on the front, and bigger rads on theback of the system. John Siegenthaler has an excellent software program for diagnosing both the parallel pressure drops incurred as well as the temperature drops for combined stream flows.

The mains have the same BTUH limitations as do regular pipe sizes based on 20 degree Delta Tea. You can spread the delta and get more btu's out of a given pipe size.

Using a 1 inch pipe for a 40K load will reduce the pressure drop associated with the main and diverters, however, you may suffer from lazy water syndrome and get air trapping in the upper regions of the piping system. Be sure and put manual vents on the top of your radiators to aid in purging because the flow of water through the side branch is so subtle that yo won't be able to power purge.

Hope this helps!

ME

[Deleted User]

A distinct advantage of 1 pipe systems...

is that you can zone baseboards or radiators or what ever individually using nonelectric thermosatatic radiator valves. If more than one board or radiator is required for a given room, simply pipe that rooms emmitters in series with one TRV before tying back into the main.

Every room in my house is an individual zone unto itself, and I didn't even have to run thermostat wires out to the individual rooms!! I used a heck of a lot less pipe too.

Less pipe = less labor = less installed cost. I think lot of contractors overlook these system designs because they view them as "old". Not so my friend. Think outside of the loop...

ME

Tom_10

more

I think I just may utilize the TRV idea. Good job on that. Its funny you mention the "old" system. I had a general contractor in this past weekend. He took one look at my BRAND NEW sunrads and said(and I quote here)"Why would anyone use this old s--t when you could just tack up baseboard. He wanted to know which junkyard I got the rads from because they were in such good shape. He needs old rads sometimes on renovation work and figured that my "junk" was in such good shape that he would use the same junkyard. I couldn't bring myself to tell him that they were brand new. Thats right around the time I threw his proposal in the garbage. Thanks for the help.
Tom