Valves on old radiators

[Heathcliff]

I have hot-water heat with an old (probably 80 year old) system. The radiators are the big old fashioned kind. I am trying to restore the valves on the radiators so that they operate and individual radiators can be turned on and off. I removed the handle (round, kind of donut-shaped thing) on one, loosened the packing the nut, if that's the right term, and applied some penetrating oil. I was able to get the stem to turn and I think it's operating now, but it only turns about

180 degrees. There seems to be a hard stop that prevents it turning more than that. Is that all it's supposed to turn? Is it a ball valve? I haven't yet turned on the heat to test whether it actually turns the radiator on and off. Just curious if someone with experience on this type of system can verify that is how the valves are supposed to work. Thanks, -- H

[Speedy Jim]

That may be all it should turn. Probably not a true ball valve as we know them; my guess would be a sleeve valve with a cutout opening on one side.

These valves may not provide full shutoff (deliberate) in order to keep a very small flow thru all the radiators.

Jim

[marson]

I replaced mine with new valves. cost about 15 bucks a radiator.

[hallerb]

replace with the thermostat type, so little used rooms can be left cooler to save bucks.

[HeatMan]

They are called Thermostatic Radiator Valves, TRV's for short.

[Heathcliff]

Thanks, that seems to be it. All 4 of the ones I loosened up did the same thing: turn about 180 degrees with a hard stop at either end. Cranked up the boiler and found that the radiators turned "off" heated up more slowly and never got quite as hot, but they still got fairly hot. I think I will try turning all the upstairs radiators "off" to see if that will correct the tendency for the upstairs to be warmer than downstairs.

I may try replacing some of the valves but that makes it a much bigger project -- more old fittings to turn (always a risk of breaking something or winding up with a leak), have to partially drain the system, etc. I am thinking I would likely have to move a radiator in order to remove it's valve, since the valves are the 90-degree bend type and would have to be rotated on a vertical axis to be removed.

Thanks, Jim, for yet another informative post.