steam heat to fhw

Eric Johnson said:

All my rads are piped bottom to bottom.

If you're concerned about the plugs breaking the radiator casting when you try to extract them (steam rads tend to corrode while hot water rads usually don't), there are other, more labor intensive ways to get them out safely. Specifically, chemicals, heat, drilling--in that order. I've had a lot of luck with a drill, hacksaw blade and a cold chisel.

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I once worked on an 1 1/2 plug in a radiator for a few hours before it turned.
At which point I realized it was a left hand pipe thread.

solarguy said:

I don't know Sled_Mack, I assume nothing until the final numbers roll out of the calculator.
Engineering is nothing more than an educated guess thru the use of mathamatics......

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I agree, if he's got the numbers to work with. Older construction can be really tricky doing a heat loss calc, too. Same with figuring out the capacity of old radiators.

Some "gut feel" goes a long way too. If his steam system keeps all the rooms warm on the coldest of nights, and it's not working it's tail off to do it, that's a valid piece of information. I guess my point is that if he does the math and comes up just a whisker shy should he really bail out on the project?

Some combination of numbers and gut feel should get to the right answer.

Usually the water goes in and out the bottom. assuming that you can get the air out, the hot water will circulate to the top by convection.
I tried to convert steam radiators to hot water. On the first one, the wrench broke the plug and I had to chip it out the rest of the way. The threads were so bad, they wouldn't re-seal. On the 2nd radiator, I gave up after breaking the casting trying to get that other bottom plug out. It didnt want to come out after 80 years or so.
Then I went out and bought some new cast iron baseboard.
good luck!

I agree with all your points Sled_Mack.

Being in the design & renewable energy business we have to look at all parts of the equation, that's my job, it's what we get paid for. Older homes can be tricky especially if the owner has no idea of what's behind the walls & how tight the envelope is. Without going thru the expense of thermal imaging to shake out what's going on, that's when past fuel consumption over a couple of heating seasons can be a real asset in finalizing the educated guess of heatloss when some of the factors are unknow.

NH Farmer, I'll get those ashrae procedures over to you sometime today.
PS, we also sell EKO boilers
Sorry webmaster, couldn't resist

I read somewhere that the more ornate radiators have more surface area and give off more heat. The dimensional detail adds surface area. Back in the day they determined the total surface area by dipping the rad in a vat of paint and drip drying it. Then they measured the average thinkness of the paint on the rad and the amount of paint missing from the dip tank. By doing the math it would give you a close measurement of actual surface area. Sounds like a lot of work to me. I forget where it was that I read it, and don't know if it is actually true but it sounds good.
Also when converting from steam to fhw you should install some rods from end to end to keep the push nipples from seperating and leaking.

Mike

Solarguy - I thought we were on the same page for the most part, just different paragraphs at first.

Mike - Interesting method for surface area. I've always been told that painting cast iron rads is bad, that it reduces the heat transfer. True, or not? Along those same lines, I read a lot of good things about putting covers over the rads. Some of the rads i got had them already. And since they were pretty plain rads, my wife really like the idea of covers. Supposedly, the covers help deflect the air into the room a bit, and reduce the amount of air that goes right up the cold wall. Anyone have any opinions on this? Just curious. It's not like my wife would let me rip them out now anyway.

I don't think you'd notice any decrease in heat transfer with a properly-piped hot water radiator. You wouldn't with mine. I think any loss, if any, would be more than compensated for by having an attractive radiator in your living space. To me, it's like having little wood stoves in every room--a place to warm your hands and other body parts. My wife will take the sheets off the line in the winter and drape them over the radiators in the sun room for that final dry, and the whole room smells like fresh linen. Nice!

We are pretty much on the same sheet of music Sled_Mack.

It's all good brother.

Where did you guys leave off with this? I too have steam radiators which are not hooked up. Was wondering if there are any options to heat with wood or... I don't know.

Is there any way you could use thermal oil to give you a similar temperature in your steam pipes as some wood boilers can use thermal oil instead of water as the heat transfer medium. Obviously you would need thermal oil pumps rather than water pumps.