Radiators piped in series.........

Solid_Fuel_Man

I was at a customer's house yesterday who had an EFM stoker/oil boiler and the whole house had CI rads.  He said this system was put in in the late 90s.  The boiler he bought used, the radiators were salvaged from several old buildings.  This system was piped in copper, and all the radiators were connected in series.  My guess is that they were originally two-pipe steam as all of them used a lower tapping, and the upper tapping on the opposite side.  With the supply being the lower one and the return being the upper one.  Isn't this totally wrong?  He said the house has heated well in the last decade, but wow I was under the impression that it was a no-no to pipe CI in simple 3/4" series and shouldn't the supply be the top tapping to force the cooler water out and not just diagonal flow up and out?  I just wanted some incite, as I've never seen anyone do this before.

Thanks to the much respected wally wet-heads

Taylor

kcopp

you're

correct. Either a monoflow, reverse and return or a manifold set is best. It will be uneven heat. Some people are in to that.....

icesailor

Just because:

Just because someone piped it like that doesn't mean that it is right or they knew what they were doing.

Hydronic hot water heating is extremely forgiving.

But like that little boy in the poem, "When he was good, he was very, very good. But when he was bad, he was AWFUL".

Solid_Fuel_Man

Seems like

it is two for two.  Series, and the return at the top.  I was just surprised it heated.  There were two loops serving a 2,000 square foot first floor, so maybe there is some forgiveness in the relatively short loops with smaller EDR on each loop.

Taylor

hot_rod

flow direction

I don't think is all that important, as long as the iron is "touched" by the fluid it will warm. Initial air removal may be easier with supply in the bottom. Here is a pic Siggy took of a panel rad heating up. Notice how the temperature moves across the entire radiator.



I'm going to infrared some cast rads with feed and return on the bottom connection to see if it warms evenly after a period of time. My hand feels it is fairly consistent after an hour or so.



As far as series piping, you just need to account for the temperature drop across each rad, just as you do with fin tube baseboard.



With a home run, manifold piping you can balance each rad, the TRV takes over the temperature regulation.

knotgrumpy

Great images!

If the water goes in one hole it would seem it's gotta go out the other eventually.

bob_46

Reinvent wheel

Exhaustive study of radiator piping , heat output and temperature distribution were done

at the University of Illinois in the first half of the last century .

icesailor

Series Piped Radiators:

Geez, it's hard enough to keep the temperature "close" between the first baseboard and the last one on a copper fin tube. Then, you want to try it with radiators?

Just don't ever put the thermostat in the room with the last radiator. The first room will need the windows open.

Solid_Fuel_Man

Bob,

As always the knowledge on this site is extraordinary!  The dead men at Illinois University, did a great job and was a great read for an early Sunday morning before getting ready for church.  The link is much appreciated and enjoyable.



Thank You All.  

icesailor

Supply or return on the top:

Sometimes, supply or return on the top isn't a problem. It can get to be a problem if they are on the same side. The water can go straight up on side and not heat the radiator. If they are diagonal, it might work diagonally. I've put a pipe in the bottom or the top to get the water to flow to the other side of the radiator. Its a matter of figuring it out, and trial and error.

Cast Iron radiators shouldn't be series looped. The first radiator is red hot while the last one is just getting warm.