Additions, Convectors, and Balancing

lgd

Really appreciate this resource as well as the book We Got Steam Heat. I live in a 100+ year old house with an addition put on in the 1990s which is now the den. Its an open floor plan so the kitchen is adjacent to the den. As best as I can tell, when they put the den on they eliminated a radiator in the kitchen and added a convector in the den (I can see the piping in the basement that is cut off and sealed). Needless to say the den and kitchen are always cold. I had a professional come in and he said the first thing I should do is balance the system and check the air vents to see if that helps before we consider anything.

I checked, changed, and adjusted my air vents in the house with vent rite adjustables. On the den convector I pulled out the Dole 3C that was there (and blocked) and replaced it with a newer version (can't remember the exact new brand, but the plumbing supply house looked it up and got it for me). I went about balancing the system so the convector would heat faster and all seemed good at 58 degrees outside.

Now that it is cold, it seems things are not so balanced. Today the den convector started fine, but then went quiet after several minutes. In the upstairs there are a couple of Danfoss thermostatic air valves that seem to crank up heat until the temperature is reached and then cut off. I am guessing this is part of the problem. I went upstairs and closed one of them (it was way too hot) and then the den convector started up again.

My goal is to get the kitchen and den warm and to balance the house. Any ideas why the convector shut down and then restarted? I am guessing the 2 radiators upstairs with the Danfosses were taking all the steam, so am considering changing them to vent rite adjustables. Will this help? Is it possible to change out the den convector for a cast iron radiator? Or should I really be thinking about adding a radiator (along with the convector) since I have a pipe in the basement that can be extended to add a radiator? The den/kitchen area totals 16'x25' with only a 56"x6"x16" convector.

Appreciate your insights and thanks in advance....

Gsmith

You are correct in that radiators that have very fast vents can "steal" steam from other radiators and convectors. As noted on this site many times to balance a 1-pipe system you should:
1. Make sure you have fast and sufficient vents at the ends of your steam mains.
2. Make sure the pressuretrol is set to a low setting, say 1.5 psi cut-out, and the inner white dial set to 1.0 (0.5 cut-in).
2. Then, after you have fast vents on the mains and pressuretrol adjusted, begin to adjust radiators and convectors so that they get hot all at the same time, or the ones in the cold rooms get hot faster than the ones in the hot rooms. I happen to like Vent-rite #1 radiator vents because they are easily adjustable and make changes easy. Start with all radiator vents on the lowest (slowest) setting and then increase the setting (speed) of venting on radiators/convectors in rooms/areas you want to get warmer faster.
3. Only after the above would I consider adding / changing radiators/convectors.
Send pictures of your boiler, pressuretrol and send size and length of steam mains and someone on this site will help you select proper equipment and settings.

lgd

Thanks for the info Gary. I had previously set my pressuretrol to 1.5 cutout and 1 on the cut in.

I did just end up changing out one of my thermostatic controls in the upstairs with a vent-rite, which seems to have helped a lot. The air vent on the thermostatic control was pretty large. Now all the radiators heat up pretty quickly at the same time.

But I still have the problem of the convector. It heats up and pumps heat, but when the thermostat shuts off the system, the kitchen/den gets cold fast. The other rooms with the cast iron radiators radiate heat much longer. Is it possible to change the convector to a cast iron radiator? How would I try to find the appropriate size radiator for the room?

All thoughts appreciated. I'll try to get those pix up as well....

Fred

Convestors don't have the same mass as cast iron radiators and they do cool down faster, while the cast iron radiators retain and release heat well after the boiler has shut down. Yes, the convector can be replaced with a radiator. What size pipe feeds that convector? Two things need to be considered when replacing it:
- The size of the supply pipe will pretty much determine how large of a radiator it can support give or take a few EDR
- The amount of heat needed for the area you need to heat. The best way to determine that is to do a heat loss calculation for that area.

Steamhead

Do a heat-loss calculation of the rooms. Then replace the convector with a cast-iron radiator that can give off that much heat. You may end up using two smaller rads rather than one big one- maybe one in the kitchen and one in the den.

We've installed steam in several additions, and as long as everything is sized properly and made of the same material, they work great.

lgd

Fred, thanks for the info. My convector has a 1" pipe into it. However, in the basement it is 1.75" pipe that has an angled piece on it that sends the 1" pipe into the den.

Steamhead, good to know about the steam you've done in your additions--can't figure out why that wasn't done here in the first place. Any calculators you can suggest to do the heat-loss calculation? Where can I find cast iron radiators and how difficult would it be to replace it. At this point I think I may be better hiring a professional....too bad you aren't in Western MA!

Fred

Google Slant-Finn Heat loss Calculator and it should bring it up. That's a good one to use.
Also, @Charlie from wmass is an excellent Steam Pro. See if you can get him to do the work.