How Are My Radiators Plumbed???

Hello all. I have a quick question regarding my cast iron radiator set up in my very old house. My house is over 100 years old and only one zone for the whole house. This spring, I am going to run another zone to the back bedroom/office/hallway, as these room are all very small and have 3 small radiators combined. The problem of course is that the living room where the thermostat is, is directly above the boiler and the L.R. stays nice and toasty warm most of the time partly due to the ambient heat that the boiler gives off, but my back room(s) are a bit cooler because of the L.R. not needing heat and not turning the C.P. on.

Anyway, this is why I want to add a separate zone for the back room to eliminate this issue. Now, my house's radiators seem to be plumbed in a circle pattern. The radiators seem to be fed off of 2 circles if you will. One circle for the hot supply and one for the cooler return. I have included a rough diagram of how I think it is basically set up. I am not sure if the hot is a complete circle or as I have it because the piping is in a very very small crawl space after it leaves the part of my basement where the boilers are. For simplicity, I have not included the 2 boilers that I have in the diagram. (one oil and the other coal of course)

I have been going over some ideas how to do this and have been making some diagrams for myself, which I wont include at this time because it is kind of messy and a little incoherent unless you are the author. lol.

I was thinking/hoping it would be as simple as cutting, capping where needed, and splicing new lines into areas that need them along with some back flow preventers where needed. For imagination's sake, the radiators in the diagram that I need a new zone for are the 3 on the left side starting at the bottom.

Thanks in advance.

Looks like it could be an old gravity system. Are the main supply/return lines 2" or larger?

Do you have valves on the living room radiators? I like separate zones as well, but if you can throttle down the radiators in the living room you may be able to balance the heat better.

No valves on any of the radiators and the main supply/return lines are 1".

it's hard to belive that you only have 1" sup & returns, and I think you drew it wrong the top rad in the middle, if you were to erase the return blue line from the rad to the tee and it becomes an ellbow to the left , you would have reverse return system which is a well ballanced system ,the 1st supplied is the last on the return and the piping is sized accordingly getting smaller as it goes away from the boiler ,it must be steel pipe w/ cast iron fittings and should be easy to zone off if you have any more ??? give me a pm

My neighbor has a similar setup, but he has fin tube, with a venturi system feeding the fin tube in the same configuration. I am not sure that cast iron systems run in the venturi configuration. Sorry I could not be more helpful

The radiators are cast iron, bit the pipe all the way to them is copper. The return line is correct, as it sits in my basement above the oil boiler and has 2 ball valves, one on each side of the cold return. It is not drawn exactly how it is set up, but that would just be a land of confusion to try to draw it all out that way. The pipes start out at 1" at the boiler, go to 3/4" to run the distance and then drop to 1/2" right at the radiators. The pipe that I am not 100% on if it Tees or just goes one way its the main hot supply. It starts out at the boilers and then runs a long distance into my crawl space where I have not ventured yet. Either way, for another zone this should be a basic cut, cap, splice correct?

Monoflow Continuous Circulation System

I could never write all this carp a second time - so take a look at all the kind advice posted by others in this thread

and ignore the rest

Kind Regards
Sting

jaimz23 wrote:ThEither way, for another zone this should be a basic cut, cap, splice correct?

simple answer

NO!

jaimz23 wrote:... the piping is in a very very small crawl space ... as simple as cutting, capping where needed, and splicing new lines into areas that need them along with some back flow preventers where needed ...

It does sound pretty simple, as long as you have a very very small plumber to do the cutting capping and splicing. Not sure what the back flow preventers are for -- to isolate one zone from the other???

I did a bit of looking around my crawlspace area from my basement with a flashlight and from what I can tell, I think I know how my plumbing is run. I have included 2 newer jpg's. 1 that is set up exactly like my home is, the other like what I am hoping I can do to make another zone in the house. These pictures are indicating where the piping is run in the basement/crawlspace and where the radiators are in each room. There is one single radiator run upstairs to the bathroom that I have left out to avoid confusion. There are no other radiators in the 2 bedrooms upstairs. Those 2 rooms get a bit cooler, but they never get cold.

Anyway, let me know if any of you that may be a little more versed in plumbing zones think this will work or if I am missing something/need to add something. From what I understand, my set up is Venturi. I have hot water radiators. The main supply and main return are 1" pipes. The long runs in between the radiators are 3/4" and the pipes going to the radiators are 1/2".

Thanks

it's Definitely not a venturi or monoflow system, it is a reverse return , with some side glitches, andit should be a simple cut & retie in please post your proposed new piping be fore you do it !! fyi a mono flow is a single main !! hence the word MONO !!!! w/ monoflow tees or venturi tees or even 2 way reducing tees facing eachother when your feeding up you would normally use I venturi tee & 1 reg rreducing tee feeding down you need 2 venturi tees 1sup &1 ret off the same main now you can check w/ the guy with the return s piped into the oil boiler and not the coal boiler low

Pardon me for my ignorance, but your response really confused me. Also, I did post my proposed piping for the new zone add on. It was the second picture in my previous post. If the piping for my zone add on looks incorrect, please feel free to take the jpg and put it in microsoft paint and correct it. I am even more confused now. Sorry. Thanks.

sorry to confuse you, and I didn't mean to sound condesending, and I really didn;t take a good look at the schematic , but after looking at it it appears that it will work , are those two torpedos located on the supply circs? if so without being there it looks like you will need flow checks, or mabe even zone valves to stop the migration of hot h2o through the system, but those can be added later if needed

You didn't sound condescending at all. No offense taken whatsoever. You are correct in assuming that the torpedo things are the circulators off of the supply line(s). The first jpg image (top one) is the way my plumbing is now with one circulator and the 2 boilers. Coal on the right and oil closer to the circulators. The bottom jpg is the way that I had planned to plumb the new zone in if it would work that way. It is basically the back 3 (top right) rooms that I want to put into their own zone and their own thermostat in the back bedroom. They all stay around the same temp and 2 of the rooms are very small (hallway and office). I just want to make sure that if it is correct to plumb the new zone in the way I have it set up in my second jpg, that I will not be messing up the zone that was already there by shortening anything and making the pressure unequal. If this looks correct, great. Will I have to use another 1" supply line coming from the new circulator that I plan to put in to replace the one I am cutting the zone away from? (I also plan on putting a supply manifold in) Also, can the return line be put anywhere into the return by the boilers or is there are certain area.

P.S. I planned on using flow check valves to eliminate any strange or reverse water flow that is unwanted.

what you have drawn will flow just fine - but it will be a "challenge" to balance the two zones for correct flow and the zone with the mixed radiation system will not perform as well as the other zone will.

OLD HOUSE RIGHT???? maybe originally designed as a gravity flow system???

Circulation rates will make or break you -

back of the bar napkin drawing ---- I would put the new radiation on its own loop with full temperature water and build a temperature reducing loop to feed the existing two zones- but with out a proper heat loss calculation and specifics of the floor materials you want to warm -- well your throwing the dice

that works too!