Steam Radiator Valves

KellyM

I am in my first winter heating season with steam heat and I still have a lot to learn. My house was built in the 20's and still has the original steam radiators. The boiler was replaced in 1997, but that seem to be the only thing that was touched. I need to replace most if not all of the radiator valves. They all leak, and I cannot repair the orignal valves. I actually cannot get them apart to replace parts internally, so I really don't have a choice. I need a suggestion for new valves, thermostatic or mechanical. Do the thermostatic models pay for themselves. Also, where is a good source for a homeowner to purchase these. Also, any other suggestion on parts to rehab/or replace to make the system run more efficiently? For example the air vents on each radiator have been painted over. Any and all suggestions are welcome.

Woody

Macon non-electric thermostatic radiator valves would the way to go. Check out our website www.maconcontrols.com, if you want call me in the morning and I will beable to give you some advise on your system. 800-423-5578. Thanks Woody

Steamhead

If that's a one-pipe system

which I suspect it is (only one pipe connection to each radiator and an air vent on each) it's not possible to throttle the flow of steam at the shutoff valve. The condensate (water) has to begin its trip back to the boiler thru the same valve, and will back up in the radiator if the valve is partly shut. If my esteemed colleagues at Macon have found a way around this I'd love to know!

The way to adjust the heating-up rate of a one-pipe radiator is at the air vent. The air has to get out before the steam can get in, so we control the rate at which the air leaves. Macon and others make thermostatic vents for this purpose. These are great for use in kitchens and bedrooms. You don't want to put them in the room where the thermostat is though.

For proper response and decreased fuel consumption, each steam main needs a properly-sized vent at its end. Measure the length and diameter (outside diameter of pipe will do) of your mains and tell us what, if any, vents are on them. We can tell you what you need from this info.

If you haven't done so already, get a copy of Dan's book "The Lost Art of Steam Heating". It's the best book I've seen about steam. Order it on the Books and More page of this site.



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KellyM

Not to sound stupid, but each radiator has two connections. One where the steam comes in and a lower connection at each vent where I assume the steam is returning to the boiler. In this case, I assume it is a two pipe system. Is this correct? If it is a two pipe system does this change your advice?

Steamhead

That's a two-pipe, air-vent system

with a shutoff valve on the inlet and the outlet, and an air vent above the outlet. This was the precursor to Vapor.

This type of system would use the same vent-mounted TRV as the one-pipe system. You don't want to put a TRV on the steam inlet since in some cases steam may come thru the return lines from another radiator, looking for the air vent. This would not only screw up the temperature regulation, but also cause banging.

Vent the steam main on this system the same as on a one-pipe system, but do not put a vent on the return line as you would in a Vapor system.

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KellyM

Manual or Thermostatic Valves

I just found out that this is probably a vapor system. The manufactuer was Moline and apparently they only made vapor systems. I am loosing a lot of heat/steam/vapor through the leaky valves. Would you the go with manual valves and leave them all open all the time, or thermostatic.

Steamhead

If it's a Moline

it's definitely Vapor! Moline was the only Vapor manufacturer I know of that used a manual shutoff on the return of each radiator. On this system there should not be air-vents on the radiators- the air goes into the return and out thru a central vent. This is covered in Dan's book "The Lost Art of Steam Heating" which you can get on the Books and More page of this site. Highly recommended.

You need to contact Tunstall. They can rebuild almost any Vapor shutoff valve, and convert them to thermostatic too. Whichever way you go, make sure you retain the "orifice" feature built into the original valves. This helps to balance the system. Tunstall's address is www.tunstall-inc.com .

Vapor systems were the Cadillac of heating in their day, and are still some of the best systems out there now. Cherish yours.

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KellyM

One more question. Famous last words. I have removed one of the moline valves in the past and they appear to have a ceramic washer of some sort, but I could not figure out how to take apart all of the valve components. Is the valve assembly soldered into place. I tried placing it in a vice and using a wrench to remove the stem assembly, but I could not get it to budge. Thanks again for your assitance. I assume when I contact Tunstall they will sell a kit to replace or repair the inner workings, but I still will need to get them apart.