Always Replace the Spud?

trivetman

I've got a few radiator valves to either repair or replace (two pipe steam system). I thought it looked like an easy job, until I started reading about replacing the radiator spud.

Why replace the spud? Are the threads not standard? Can I keep the same spud if the threads are the same between old and new valve?

What if I replace the old valve with a TRV, which is a possibility on a few radiators. Does that change things?

Here's a pic of one of the old valves

STEAM DOCTOR

The threads are always standard. Bigger issue is the mating of the two parts of the union. I always replace both parts. Right thing to do and not very interested in callbacks

The Steam Whisperer

The threads on the union connection are not standardized and neither is the mating surface shape. On rare occasions you can get lucky. We use Marsh valves exclusively ..... I don't think there are any well made packed type valves anymore. The Marsh valves are beefy and packless. We often use hundreds of them a year.

Jamie Hall

It's not the threads. As @STEAM DOCTOR said, it's the mating surfaces of the union. Sometimes you get lucky. Sometimes... not so much.

ethicalpaul

They’re very straightforward to remove after your first one, if that’s any consolation.

STEAM DOCTOR

> @STEAM DOCTOR said:
> The threads are always standard. Bigger issue is the mating of the two parts of the union. I always replace both parts. Right thing to do and not very interested in callbacks

Typo. Meant to say that threads are not always the same. Usually they are but not always. Mating is the concern.

trivetman

Well...we’ll see when I get to it. Now that i think more about it, the valves may well be repairable (aside from the possible change to TRV’s). The problem with a couple of them is they just spin freely. There is no tension in the knob to keep it in place. Might this be as simple as tightening the packing nut?

EBEBRATT-Ed

@trivetman

I usually alwys change them as I find they seldom match. An internal spud wrench is hit or miss. I have had some luck taking a piece of square steel stock and grinding it so it will fit in the spud and putting a wrench on that.

Also, I have had sucess cutting the nut and taking the nut off. Then you can get a good bite with a pipe wrench on what remains. Jamb something inside the spud so it doesn't colapse when you wrench it out

jumper

ethicalpaul said:

They’re very straightforward to remove after your first one, if that’s any consolation.

don't you mean sometimes? How about removing spuds from old toilet bowls?

ethicalpaul

You have radiator spuds in your toilet bowl?

jumper

ethicalpaul said:

You have radiator spuds in your toilet bowl?

I was expressing my admiration for you guys who can remove radiator spuds and for the cast iron that doesn't fuse after many decades.
The subject of removing spuds reminded me of an assignment long ago. Building full of toilets with gooseneck connection between tank and bowl. I was to conserve those goosenecks. Was my supervisor trying to make me quit?

Alan (California Radiant) Forbes

I just finished rebuilding an old fashioned American Standard two-piece toilet. I have only admiration for the dead men who worked back then as plumbers and pipe fitters. Everything was heavy and difficult: toilet and radiator spuds, lead and oakum joints, thick cast iron or china fixtures, threaded pipe. And usually, all their work was plumb and level and lasted for 100 years. For those that take pride in their work, I drink a toast to you.