Adjustments on large pre-WW2 Hot Water Finned Radiators

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Title says it all - 1920s colonial with bulky radiators currently fed by modern Burnham V8 Boiler.
General Description: On the radiators themselves there are two types of adjustments(at least they both *look like* adjustments): A large knob close to the floor at one end of each radiator. And, two screws, one at each end 'fin', about 1/3rd way up from the bottom of the unit. See:
http://www.salvosites.com/images/userimgs/10756/52632_4.jpg (Look carefully towards bottom - you will see screw I'm referring to) At top of fin on one end is the bleeder valve - no explanation necessary.
Question#1: What is the "nominal" or "default" position of those knobs - I'm assuming 1/2way. That way rooms needing more heat can just be opened up a little more and those needing less heat can be closed a little. Currently, I have the units upstairs turned fully counter-clockwise - Open as indicated on the knob-, and the units downstairs(closest to the thermostat) halfway open. Please advise.
Question#2: What is function of the flat-head screws in each end-fin of each radiator unit, and how should they be ajdusted.
Notes: Some of these radiators have received multiple coats of paint so turning items in Q#2 will be difficult at best. All radiators get plenty hot, especially this past weekend with lows in the low teens, and are evenly hot - no coldspots.
Thanks,
-ChrisCoaster
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Bottom screw is probably one end of a rod that goes all the way to the other end to hold the radiator sections together... Do not loosen or you will have a flood.
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On Tue, 17 Jan 2012 19:48:36 -0800 (PST), "hr(bob) snipped-for-privacy@att.net"

Right, don't fool with that. I've re-sized these in my old house. Every section has a nipple on one side and a female on the other, top and bottom. Mine had end sections without the plug you see on that picture sealing the female side. The nipple is a press fit into the female side.
Rods with threaded ends on top and bottom draw the sections together. You have to work the sections apart with wedges after you remove the rods. I bought all-thread rods to put mine back together, since I shortened the radiators and the old rod was too long and I didn't have the right die set. Cleaned up the nipples and females and used Permatex number 2 I think. Worked out fine. There's different designs though. Never saw that one. Mine were designed where the rods didn't penetrate the water jacket. I wouldn't fool around with those old valves too much unless you're prepared to repack them. See how the heat is with all valves wide open. Or leave the ones half-closed alone if that's good. If you work them too much they may start leaking at the stem.
--Vic
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To all: Thanks for the info received so far. First I must clarify: On my radiators there is no rod behind these flathead screws. The rods on these particular rads are connected at both ends with large hexagonal nuts - two on top and two on bottom.
I have safely revived the full range of motion of the large hand valves on all radiators. There is a flathead screw holding the plastic round handle to the actual valve mech inside- most of these were easily tightened a half turn or more with a screwdriver. My feeling is that they loosened up over time.
When the system was "cold" I fed water into the boiler up from 12 to 15psi, then bled all radiators starting with a small one in the kitchen, then the dining, etc, finishing with the bedrooms upstairs. I did this betw Christmas and New Year's, and then bled only yesterday. On this last bleed cycle I got no hiss just steady stream of water from each unit. It is AMAZING how warm the house stays relative to how cold it is outdoors when the radiator system is so well primed and sludge free! Just these few simple steps can save a few 'no heat' calls.
I would still like some more insight on the large 'user' knobs - 1/2 way by default or all the way open?
-CC
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On Wed, 18 Jan 2012 05:29:10 -0800 (PST), ChrisCoaster

Just do what works for best heat. Keep in mind that working a valve stem will eventually lead to leaking around the packing, older the valve the more likely. Also that some valves have a backseat so that when fully opened there is no pressure on the stem packing. I would open them all fully, and only close down if there's too much heat. Like uncomfortable in a room. I wouldn't be opening and closing them all the time.
--Vic
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or replace with temperature control valves, you can set temp in each room indenpendtly.
much more energy efficent
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You forgot the part about telling them to reduce the water flow through this heat exchanger to the minimum possible, the air flow too, per your screwy theories about how radiators and heat exchangers work.
I say he gets the most heat out with the valve wide open and the most airflow possible over the radiator.
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And the room will be cooler too, fruitcake.

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But harry, have you figured out physics yet? For any given water flow rate and incoming water temperature going through a radiator, how do you get the maximum heat possible out of this simple heat exchanger?
Is it:
A - Move as much air through the radiator as possible, up to the point where the airflow is sufficient to remove all the heat.
B - Move as little air through the radiator as possbile so the air coming out will be as hot as possible?
Can you answer this simple test correctly this time or are you going to continue to confuse heat with temperature?
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wrote:

SMH(scratching my hair in this case)
Now I'm confused! Please educate us!
-CC
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No, as usual you didn't answer the simple question and instead resorted to hurling insults.
So, we're waiting, is the answer A or B?

Pay attention. The question was: With any given water flow rate, do I get more heat out of the radiator with MORE airflow past it? More heat until I finally reach the maximum heat recovery, which would be when the water temp leaving the radiator equals the air temp? In another thread you claimed I don't get more heat with more airflow. Which of course is why you won't answer the simple, direct question.

Again, pay attention. You're changing the question. The volume of water entering the radiator is fixed. Do I get MORE heat out by moving MORE air past the radiator, yes or no?
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Consider the whole system as much as you want. It does not change the physics which say that you get more heat out of a water to air heat exchanger the more airflow you put through it. Until you reach the point where the outgoing air and water temperature are equal. Therefore in the case of the solar heat exchanger inserted into the duct work to get the most heat out of it, you want all the furnace air moving past it, getting the highest CFM possible.

Does not change the above physics.

Wrong. Once again you are confusing heat and temperature. You get MORE heat out of it by moving the most water through it. That way you have the largest delta between the cooler water and the solar panels. To see how illogical what you've stated is, just consider extremes. Let's say I have 80F water entering the solar array. Slow the flow down to a trickle and you could have 160F water. Let it run for a minute and you get a pint of 180F water. Now instead open the valve wide and you get 10 GPM. In a minute you have 10 gallons of water that is heated to 100F. Are you going to claim that the pint of water contains more heat than the 10 gallons? That more heat was transferred to that pint than to the 10 gallons?

.>
Uh huh and you transfer more of it by moving a cooler fluid past it, not by slowing the flow down so you get hotter water. Again you're confusing heat and temperature. With a little water flow I could have 160F water. With a large water flow I could have 100F water and I would be extracting MORE heat. The water is cooler, but there is way more MASS being heated. Capiche?

How useful it is or isn't depends on what the application needs. As I recall we were discussing how to get the most heat out of a radiator or heat exchanger. And you do that by moving the MOST airflow possible past it until you reach the point where the air and water exiting are at the same temperature. Then you have extracted all the heat possible and further increases in airflow don't produce any further increase in heat. It's really very simple physics and it works the same for the heat exchanger, a home radiator, a car radiator, etc.
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On Sun, 22 Jan 2012 10:12:31 -0800 (PST), " snipped-for-privacy@optonline.net"

All your physics is correct. What's that got to do with harry? I once mentioned I cranked down the gas supply on my old boiler because it was throwing massive heat up the chimney. The burners were obviously overpowering the heat exchanger capacity to absorb heat.
It was an old thing designed when NG was dirt cheap. Of course I adjusted air to the flame and had good flame, and of course cycle-on increased. But my gas usage decreased. harry still didn't like that.
I always wanted a small fan across my radiator fins when I had hot water heat, to aid convection. Never did it though. Too much work, and they worked well enough.
--Vic
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Harry's physics is totally wrong, that's the problem. He doesn't understand the difference between heat and temperature, as evidenced by nonsense such as this:
"> There is only so much radiation falling on the solar heater. Ifyou

So, he thinks you get more heat out of the solar array by passing a pint of water through it and getting a pint of say 160F water instead of 10 gallons of 100F water. He continously confuses temperature with heat and doesn't account for MASS in anything.

Funny thing in all this is that he has the nerve to constantly carp about the US and claim that we don't have efficient furnaces, boilers, etc. Yet it's clear he doesn't even understand high school physics. In fact, for most of what I've tried to explain to him, just practical everyday experience is all you need.

Nah, couldn't be. According to harry, you get the most heat when the air from that radiator is hottest. You should put a box around it.
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wrote:

So pretty much what I'm getting here is that #1 - Still water runs cold(keep water moving) and #2 - Heating will be more efficient if I place electric fans to blow across radiators where I need more heat, correct?
Ver-r-r-y interesting...
http://nakedphilly.com/wp-content/uploads/2011/11/Very-Interesting-mouth-closed-eyes-open-wide.png
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over cooling the water temp will cause cool exhaust air from fans making you feel cooler
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Excuse me, the entire discussion we were having was about the physics of heat transfer, NOT about how people perceive heat. Sure, 200 CFM of air coming out of a register that is just a couple degrees above room temperature can feel cooler than 10 CFM of air that is 20 deg hotter than room temperature. That has nothing to with which one puts more heat into the house.
In other words, you're once again confusing heat with temperature.
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wrote:

well ultimately what matters more?
the most heat is extracted buy we feel like were freezing?
or a little less heat transfer but were warm and toasty feeling?
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t> wrote:

That's an entirely different subject. The issue was how you extract the most heat out of a water to air heat exchanger, ie simple physics. You do that by moving the most air possible past it, a fact which harry can't grasp.
I agree that you might want the air to be hotter. In that case you move less air pass it, getting warmer air, but you are then getting less than the maximum possible heat out the heat exchanger. The issue started over an attempt to use solar panels that are already heating a hot water tank. Now you have panels that are likely sized to a water heater and already doing duty heating that. So, there probably isn't a lot of spare heat available. The issue becomes if you're not extracting the max heat possible from the heat exchanger, or close to it, you may not be getting enough heat out of it for it to be worth it at all.
That was why i said you might as well just put all the furnace airflow through it since that would give you the most heat going into the house possible. Which, of course, harry vehemently disagreed with, the physics be damned.
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wrote:

Reminds me of a friend from Poland I knew. Ever see the TV series Banacek with George Peppard? He would spout "Polish proverbs" like "If you're not sure that it's potato borscht, there could be orphans working in the mines." "Though the hippopotamus has no sting, the wise man would prefer to be sat upon by the bee." "A truly wise man never plays leapfrog with a unicorn." "If a wolf is after your sleigh throw him a raisin cookie, but don't stop to bake him a cake." "Just because the cat has her kittens in the oven doesn't make them biscuits."
Got those from Wiki, but they don't mention how most "real" Polish proverbs work. They rhyme, and follow the gender rules of the Polish language. Might work the same for other languages, don't know. So you ask me in Polish "What time is it?" I can answer in Polish, "She went to take a shit, and hasn't come back yet." That answer makes perfect sense in Polish. Even sounds "poetic." Any Polak here knows that.
Anyway, back to your idea on heat. My Polish friend once said to me. "It doesn't matter who you sleep with. It only matters that you sleep."
You can take it from there.
--Vic
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