removing 80 year old pressure relief?

ChrisJ

Finally talked a friend into installing a new pressure relief on his 80+ year old three pass boiler.



I'm wondering how hard its going to be to remove the hold one?  My first assumption is to throw a 2 foot wrench on it and see what happens.



Opinions?



Plans are to install a modern 15PSI relief with a 1" to 3/4" brass bushing.

Hap_Hazzard

Does it work?

Granted it's not up to code, but there are probably other things about that boiler that aren't. If it doesn't open you might want to look for another tapping.

ChrisJ

Does it work

I have no idea.

I assume its like a modern one, if you test it it'll leak from then on.



This is why I'm thinking the best bet is to replace it. As far as other tappings, same story, something steel screwed into them.

BobC

Better part of valor

Getting that valve out might prove to be a tough chore and there is the possibility of doing damage to the boiler.



Perhaps the better part of valor would be to let it be and install a second pressuretrol as a backup. It loos like the fittings on the gauge glass are brass so perhaps you could fit a pigtail and pressuretrol there.



Bob

ChrisJ

Replies

Thanks for the responses.



A second Pressuretrol I suppose is an option, though kind of a pricey one to sell a friend.  I'm thinking to remove the old relief if it doesn't just turn out, it could be treated like a steam pipe.  Cut, split and folded in on it self to pulll it out of the threads.



Question is, how clean are those threads going to be.  If its like my steam pipes were those came out beautiful.



Surely there is a pro out there that has removed and replaces these with new?

Charlie from wmass

I just changed one on my own boiler

My boiler was installed in 1910 and is a snow man. I should change the boiler soon yet I keep putting it off. The relief valve let loose last month so I had a choice to change it or change the boiler. Since it was Saturday night I chose to change the relief valve. It promptly snapped off the boiler using an 18" wrench. I then spent 2 hours cutting out the stub left in the boiler. Then I had to re tap the threads. Would I do it again, sure I am dumb like that. Was it a pain in the posterior? Yes it was. Note I have been working on boilers since I was 3, I am over 40 now. I am also second generation to the trade. So if you want to try go for it, just wait until May or June and have the money aside for a boiler replacement as you could crack the boiler or turn a chunk right out the top if the boiler has had a lot of fresh water added over the years.

pipeking

second that charlie

i've gotten pretty good at cutting out broken males from females. if it does snap, a sawzall blade is prolly to big to fit inside to cut, what i've done is ground down the blade on a bench grinder untill it fits. i've also used a metal blade on a jigsaw, when a grinder wasn't avalable. if u r extremly scared of breaking it heatup the cast with a torch and cool down the valve with ice. but i'll tell u the time it takes to do that i could prolly cut and chip it out if it snaped, like i said i've gotten pretty good at it! GOOD LUCK!!

ChrisJ

Cutting

Should I just cut it off rather than risk breaking it off?  This way I would have some sticking out that I could fold in rather than risk hammering with a chisel near the threads.



I'm wondering if vice-grips would actually work to slowly crush the valve stem in on it self.





Anyone know if that valve goes right into the top of the block, or is there some kind of extending piece?  It looks like a hex shaped flange or something surrounded by white insulation (asbestos? who knows..)

Charlie from wmass

I would advise

find another location for the new relief valve, make sure the pressuretrol is working properly and leave that things alone unless it leaks. I DO NOT mess with Asbestos. I do not advise you to either. There has to be a better location to add the valve. Add to where the trycocks are if you need to. If they are brass they will come out easier.

Hap_Hazzard

I was going to suggest that.

But it sounds better coming from one of the guys that actually know what they're talking about. :-)

ChrisJ

Tricocks

My concern about that is size as well as location.

Will a safety valve be effective located so close to the water line and through a much smaller opening?



Another option may be the weighted device opposite of the relief, I believe it originally regulated pressure by opening and closing dampers while burning coal.



Not sure what that is made out of though?  If its brass that would be a piece of cake, if not then its in the same boat as the relief.

RJ_4

prv

Soak the threads overnight in lets go or wd-40 overnight  spray it on numerous times and let it sit,       I would pick a time when your boiler is off as not to get toxic fumes.   also in old fitter trick was to heat up the cast iron  and throw on some cold water in the area your loosening, the expansion and than contraction of dissimilar metals will alot of time break the rust etc loose.   Pipe King was talking about this.

Hap_Hazzard

They had pipe joint compound 80 years ago.

When plumbers and steamfitters make joints they apply thread sealant (aka pipe dope, pipe joint compound) to prevent any liquid from penetrating the joint. It works really well, which makes penetrating oil completely useless.

Charlie from wmass

the issue is

the metals are not dissimilar, they are both cast iron. Throwing cold water on hot cast iron is a great way to crack it wide open. Cast iron does not like changing temps too quickly. Try the draft regulating bellows.

MikeyB

New Relief

You can try applying wax from a candle or even a toilet wax gasket, run the boiler for a while and let it heat up, apply the wax and watch it wick into the threads, then put your wrench on it a give it a turn, if it turns shut the boiler down, let it cool a little and remove the valve from the tapping, we have used candle wax on just about every type of application to remove tuff joints. But as Charlie mentioned try doing it in the warmer months in case you run into a problem

Hap_Hazzard

Has anyone actually tried this?

I keep hearing this suggestion, but I have yet to hear from anyone who has actually tried it--let alone had any success with it. I don't see how anything is going to "wick into" threads that have been sealed with pipe joint compound for 80 years. Pipe joint compound doesn't just selectively seal threads against water. Read the label.



I'd call this another urban legend.

Hap_Hazzard

Applying heat.

I think a lot of guys are under the impression this will work because, as every auto mechanic knows, if you heat a nut that's rusted onto a stud or bolt, you can spin it off, even though the nut and bolt are both made of steel.



But there you have two things working in your favor. First, you can apply heat directly to the nut, so it expands faster. Second, the nut, being a ring, expands as a function of its circumference, while the bolt, being solid, only expands as a function of its diameter, so the nut expands at three time the rate. As you know, neither of those applies here. You can't heat up just the part of the cast iron that holds the threads because the cast iron conducts the heat too well. You'd use several bottles of propane just to get it warm, and if you could heat it faster it would crack.

MikeyB

Candle

Hap, We have done it plenty of times, we keep a box of candles on site at every Building i have worked in, The old Plumbing & Heating outfits i worked for in queens NY taught me this trick on residential steam systems years ago, and I have used this trick for the past 17 years in Commercial Buildings in NYC on alot of Steam systems, Con Edison is also a big fan of using the candles on old bolts/nuts for High Pressure Steam work , and i have successfully disassembled screw pipe from 1/4" up to  3" with this trick, Give it a shot, what do you have to lose? And i have used Toilet Wax rings when i didn't have any candles left and it worked just as good.

RJ_4

prv

If the relief valve is brass and the boiler cast iron,  heating and than shocking with cold water has worked for me several times, also have used penetrating fluid in the past, has worked for me

RJ_4

prv

One more thing I have used over the years on all tough to remove fittings, valves and pipe.  Tighten the old valve, fitting first, alot of time this will break loose rust and corrosion. I always try to use a 24 inch pipe wrench and in some cases a 36 inch wrench.

ChrisJ

Done!

It went pretty easy, simply turned out using a 2 foot wrench.  Also successfully repiped the water feed to the boiler in copper and brass.  The original galvanized pipe actually closed up completely this fall and he couldn't add water that way anymore.





Before anyone mentions it, I know I didn't put a union on the outlet of the PRV like I should have to make changing it easy.  But money was tight and I figure we'll just cut it and put a union in it at that time if we end up changing it in the future.

Hap_Hazzard

Speaking of saving money...

I hope you used type "M" copper on the PRV.

ChrisJ

Type M

Nope, I'm 90% sure it was L, but it was scrap we had laying around.

Charlie from wmass

Glad it went smoothly

I have to laugh as I know what a nightmare mine was and I have done this since I was out of diapers.