Replacing Radiator Supply Valves

cubicacres

We're replacing some radiator supply valves and noticed while the radiator & riser with the valve comes apart easily enough with our pipe wrenches, we haven't been able to get the spud out of the radiator.

We saw the spud & compression fitting appear to be the same size as the new valve spud & compression fittings, so we left the old ones in the radiator. A few spuds broke the ears off when we tried to remove them with our spud wrench, and a few more had an intermediate size that wouldn't even fit our spud wrench for attempted removal. We didn't want to use a hacksaw or sawzall to cut them, for fear of damaging the female theads inside the radiator.

After firing the boiler back up, we didn't notice any leaks yet, so maybe so far so good? Are there any issues with keeping the old spud in the radiator and just replacing the valve if they seem to be the same size compression fitting?

Jamie Hall

If it doesn't leak, you're very lucky -- and then there's not a problem. But it's not a compression fitting, it's a union, and usually it's not such a great idea to just replace half of a union.

FranklinD

When I replaced a radiator and a few valves, I found that the spud wrench would just shear off the tabs inside the spud. I ended up having to use a 24" pipe wrench to get them out, but they did come out. They're pretty soft (brass) and once the pipe wrench started to deform them they began to turn out.

JUGHNE

On the other hand, this method seems to cut both ways. I have had spuds/nipples become more difficult as they egg shaped. I believe your spud was just at the at the point of breaking loose as the deformation began.
If you saw off the nose of the spud and get the union nut out of the way there is more wrench jaw area available.

So I have inserted a smaller pipe or bolt inside the nipple to prevent collapsing. Also, even have had the spud wrench unscrew some old ones.....pleasant surprise.

Have had to cut out several.

nicholas bonham-carter

There is usually not any benefit in replacing valves. The newer ones will be of lower quality than the old, maybe not suitable for steam, and you don't want to close off one-pipe valves, so what purpose would there be in the change?
The time you would see some leaking will be next winter when the boiler is working hard to keep up at design temperature.--NBC

newagedawn

not a good idea to replace half the union, but no leaks you got lucky use you pipe wrech to get the nipple out the hard part is getting the new one in, good luck

MilanD

No one is mentioning penetrating oils lile kroil or pb blaster. I don't even attempt disassembling any old rusty parts without it. In my book doing it "dry" is asking for trouble.

MilanD

Oh, one more thing: large cheater bar is a must, and instead of applying steady pressure on it, a slight yank/jerk is much better to break the 100-years of 2 parts being stuck together.

EBEBRATT-Ed

Find some square steel stock and using a grinder grind the steel until it fits into the spud snugly. Put a wrench on the steel.

or cut the nut off the spud with a grinder making a few cuts in it to split the nut. Now you have enough to grab with a pipe wrench. Put a bolt or pipe nipple inside to keep it from collapsing as @JUGHNE suggested.

Unusual that the unions would match up.

cubicacres

We ran max heat on the tekmar for an hour to check for leaks, and the 2 we did today leaked, so we got them off with some penetrating oil, the spud wrench inside & a cheater with the pipe wrench after cutting the nut off.

The other 2 we did yesterday but left the old spud & nut in the radiator didn't leak, so that was interesting. Suspected the 2 that leaked didn't lien up as well-we had to pull the riser up a little on one, & the other popped on the threads & wasn't square, so we could imagine them leaking easier.

Is running max heat for a while, then visually checking all radiator valves the best way to verify which ones are leaking or not? If not leaking, leave it alone, if leaking, replace both halves of the union/supply valve?

Jamie Hall

First step for a potentially leaking valve or union is to clearly identify exactly where the leak is. Sounds obvious. If it's at the valve stem, it can almost always be repaired by slightly tightening the packing nut or repacking (not all valves qualify there). If it's at the union, the best thing to do is to open the union and make sure that both faces are perfectly clean and smooth; no gunk, no leftover dope from a knucklehead, and check the faces to make sure they haven't been scratched or damaged. If all is well there, then put the union back together. It may help to rock the radiator very slightly at the last stages of tightening -- and it will help a lot is you make sure that the pipes on the two sides are aligned -- vertically, horizontally, and straight. Unions are not designed nor meant to take up misalignment. With a radiator, shims may help,

Replacement is a last resort.

RJ_4

All great ideas,, also tighten first than loosen, using xtra large channel locks. There is great video i think Hot Rod made showing removing the spud. I found that if I stick with American made valves the chance of everything matching up is better

cubicacres

Does putting teflon tape and/or pipe dope on the valve threads when you have it apart to check/replace it help with the seal, or tend to cause more problems and should be left off?

nicholas bonham-carter

Use some dishwashing liquid on the mating faces to enable them to line up, with a little rocking. Pipe dope has enough solids to prevent the intimate metal to metal contact which is needed.
Some liquid on the union threaded ring could also help with tightening.--NBC

Jamie Hall

cubicacres said:

Does putting teflon tape and/or pipe dope on the valve threads when you have it apart to check/replace it help with the seal, or tend to cause more problems and should be left off?

No. Pipe dope or teflon tape is meant to seal a threaded connection -- but a union does not depend on the threads for the seal, but rather on the metal to metal contact of the union faces. @nicholas bonham-carter 's suggestion of a little -- a very little -- bit of dish soap on the faces sometimes helps. But nothing else.

cubicacres

Thanks. I'm hoping we can simulate a cold winter day by running the tekmar boiler controller at max heat setting for an hour or two and check each radiator for leaks.

Have you noticed leaks pop up ocasionally over time, or do you think something has to stress the unions to start them leaking if they haven't before?
I suppose an annual check on a cold day is useful to keep an eye on things. Our tenants usually aren't as observant as we are about these things, but we can schedule a whole-building 21 radiator check occasionally.

Jamie Hall

If the leaks are in the union, rather than the valve itself (which is almost always a packing problem), they do pop up now and then. Usually when a radiator has been wiggled strenuously or otherwise abused. In a rental building? Oh yeah. So it's worth checking them for tightness now and then. Just rock the radiator a bit while putting a little torque on the union nut.