Parts for Cast Iron Boilers

Mark Mathys

Howdy

My wife and I recently bought a big house with hotwater heat and a bunch of cast iron radiators. The control valve appears to be frozen on several of the radiators and will not turn. Can a person get parts for these valves? or is there something we can to to loosen them up so they will turn?

Thanks

Mark

Mike T., Swampeast MO

First try some repeated sprayings of silicon--not the pure stuff--the kind that lists petroleum distillate as the prime ingredient. Two or three times a day for a few days will probably do the trick. I'd remove the handles to ensure the spray goes where it should--where the shaft goes into the packing retainer nut. Once free give a couple drops of light oil. If for some reason it starts leaking a bit from around the shaft, tighten the retainer nut a bit--but remember it's brass (soft) so don't tighten too much!

Rad valves are still made but are surprisingly expensive and might be hard to find in your area.

If this doesn't free the valve the originals can most likely be repaired by removing them, HEAVY dousing with the above (and/or a soak in oil), CLEANING and replacement. Of course you'll have to drain the system first! If going to this point you should probably replace the stem packing while you're at it.

Mark Mathys

Radiator Repair

Hi Mike

Thanks for the help, what is the packing material usually made of? I remember seeing some graphite rope material used someplace. Can the packing be changed with the system pressurized or will I need to drain it first.

Do you have any recommendations for cleaning the radiators? I don't know if they have scale build-up or not but wouldn't be surprised.

Thanks

Mark

Mike T., Swampeast MO

I really don't know what stem packing is made from other than to say it seems to be fibers impregnated with a non-drying resiny substance. Good plumbing stores will have many different sizes of pre-formed packing--if none fit you can use the stuff that looks like teflon tape formed into a little rope.

You have to drain the system to replace the packing. Again all it usually takes is a slight firming of the packing nut and I can't think of any reason to replace the packing unless this doesn't work or you've removed the valve anyway...

Generally hot water radiators don't need to be cleaned inside. The bottoms of the sections provide quite a large space for gunk to accumulate; the generally low water velocity doesn't tend to pick up or remove larger particles; and there isn't much corrosion taking place inside a sealed system to begin with... If however, you have removed the radiator for some reason, it won't hurt to flush and rotate the radiator a few times. I wouldn't use any chemicals to try to clean any farther as you'd probably just remove the "protective" patina and cause new corrosion.

With reasonably maintained hot water systems (even those that operated under gravity for decades) you'd probably be quite shocked how little corrosion/scale there is in both the piping and the rads. The internal passages in cast iron radiators are so large that even lots of buildup would have little if any effect on flow.

An old heating guy in St. Louis told me that he'd never seen a cast iron WATER radiator fail from anything other than freezing or EXTREME impact. He did say though that steam rads in poorly maintained systems like to develop "nipple rot". Our local water is extremely hard, very alkaline and highly chlorinated. Like in St. Louis it comes from the Mississippi River, but I believe their source is taken before the Muddy Missouri joins. Other water chemistries probably affect things differently, but I haven't heard of an inside iron radiator cleaning requirement with ANY.