Replacing 20-year old bakelite radiator knobs with themostatic new ones; good idea or not?

Our decades old radiators in our 1929 house have old bakelite knobs, sealed with waxed thread. While they look nice oldish, they are hard to operate. Mainly because the arrows (indicating warmer/colder) and numbers on them are small and faded, and very hard to make out. It is a bit of a gamble when turning them, and trying to make out which way will turn the heat up and which way will turn them closed. They seem to have only three positions; Open all the way, closed all the way, and, all positions in between, the Almost Inaudible High Squiek. :mad:
Another problem is that some of the radiators seem to be at the end of the line and hardly get any heat, leaving their rooms perpetually cold; while some get way too hot.

I’ve asked an plumber for an estimate on how to improve the heating. He told me I’d need to install pressure valves that would regulate the amount of hot water going to a radiator. That seemed like a good idea, although I don’t know anything about such things.

He also advised me to install new thermostatic radiator caps. He said radiator caps also wear out after twenty years, so they should be replaced anyway. The newer models also have the advantage that I would be able to set the heating to a clear position. But the central heating would be regulated by the thermostat in the living room.

So do technically inclined Doper agree with my plumber, and should I replace my bakelite radiator caps/knobs with ugly, but servicable new ones? Does anyone want the old ones?

Reported. Don’t click the link in this semi-russian garbage, it leads to bad places.

I believe in the UK thermostatic valves are now a requirement. I had to replace the entire radiator in one room. Despite it being smaller, it puts out way more heat. Modern technology has moved on when it comes to radiators. In your place I would consider replacing the rads also.

A few thoughts:

  1. If by plumber you mean someone who specializes in water supply piping and drains, you’re talking to wrong guy. You need to talk to a heating specialist.

  2. What type of radiator system do you have? Steam, one-pipe water, two-pipe hot water? I have a two-pipe hot water system, and it’s silent except for occasional gurgling of air bubbles. The only radiators in my experience that squeak (or rather hiss) use steam.

  3. If you’ve got some radiators that are hot and some that are cold, something is seriously goofed up. A properly designed hot-water radiator system, certainly of the two-pipe variety, is notable for the uniformity of its heating. While I have valves on all my radiators, I don’t use them unless I want to shut off the heat in an unused room; it’s not necessary to do this to equalize the heat. I don’t have much personal experience with steam radiators but my impression is they’re more persnickety. A fellow named Dan Holohan is the principal online steam-heat guru I know about.

  4. I installed a few thermostatically controlled valves made by Danfoss, a Scandinavian company (they look similar to the one you link to), but don’t really use them, and I’ve never come across anyone else in the U.S. who does. (Admittedly most U.S. heating systems nowadays are gas forced air.) I guess I’d use them if I couldn’t get my radiators to heat uniformly any other way, but first I’d want to figure out what was wrong with my system. If it’s simply piped improperly, there’s not much you can do about it now, but at least you’ll have a better grasp of the problem.

If you can provide any more detail on your system, that might help us get a better fix on things.

The component you linked to is a Honeywell radiator thermostat. I assume you have a steam system. Here is a very useful video from a popular TV show here called “This Old House” which will show you exactly how these devices can be installed and how they work. I live with steam heat and I have installed them on my radiators. They work just fine.

On the radiators that aren’t working, it is possible that the air vent has water that has collected in the air vent (water vapor is leaving the vent, and it is common for water vapor to condense and essentially fill the vent with water, closing it off and effectively shutting off the radiator) You may try removing the older air vents and turning them upside down and shaking them. If there is water in them it can be simply shaken out and the water will be removed. Reinstall and the radiator may work just fine.


Thanks Ed and raindog. I looked it up, but I guess I do have two pipe hot water heating, not steam. The knobs I linked to are not the exact ones, but one of the brands the plumber/heating man mentioned was indeed Danfoss.
The system or radiator isn’t what is making the noise; it is the knob itself.

So I guess I will let the guy do both the things he recommended; install valves and calibrate the prssure so each radiator gets enough hot water, plus have those knobs replaced with thermostatic ones so I can regulate the heating in the separate rooms, or at least as much as possible given that the thermostat in the livingroom determines if the heating is “on” or " off".

Thermostatically controlled valves will help in the rooms that overheat; they’re not necessarily going to do you any good in the rooms that stay cold, unless the rooms that overheat are near the thermostat (since the furnace won’t cycle off so quickly). Still, I’d be curious to know why a two-pipe system was so unbalanced. Did your heating guy venture an opinion about that? What kind of house layout do you have, mostly vertical or horizontal? Is the house well insulated? Does the heating system appear to have been modified over time - for example, are different styles of piping and radiator used, is there a mix of baseboard heaters and radiators (bad idea), or are there other obviously funky aspects of the system suggesting amateur intervention?