Removing a Pressure Relief Valve

TeachMeSteam

Hey everyone. I'm a super for a commercial building. I need to temporarily remove the pressure relief valve on our steam boiler. This is a commercial boiler (a few million BTU). I was hoping you guys could help me with a few basic questions.

- In order to loosen the threads, is there a special penetrating oil that I need to use like krano? (i'm assuming I have to be careful that I don't get any of this stuff near the section gaskets.)

- How careful do I have to be with the valve itself? I know these things are pretty expensive. So, I want to know how sensitive these things are to stuff like light hammering in order to loosen the threads.

- When putting the valve back on, what type of thread sealant is recommended?

Normally, I would call our maintenance company for repairs but this is simply for taking off and putting the valve back on.

Thanks guys.

bmwpowere36m3

Why are you removing it and then reinstalling it… leaking?

To remove it, I would just use two pipe wrenches of the proper length (one on the valve and another to support the pipe). No need for penetrant, no hammering.

As far a sealant… everyone has their own preferences.

JUGHNE

Are you re-installing the same valve or replacing it because it leaks? If re-install have you tested it to be sure it reseals? Even before testing I would locate a new one and check for availability in your area just in case. If your in a city probably no problem, but for someone like me in the outback it might be overnight. And it is getting really cold for one overnight outage.

nicholas bonham-carter

Be careful not to generate an incident such as this:

http://philadelphia.cbslocal.com/2016/01/13/1-injured-phila-elementary-school-evacuated-after-boiler-explodes/

TeachMeSteam

Thanks for the heads up. I've been around the boiler for 15 years. So although I'm pretty useless, I've lurked on this site for a long time and I know at least how to keep the pressure down.

I just want to be careful. I don't want to ruin the pressure valve which is probably a few hundred dollars in itself.

After cooling and releasing any possible pressure, I tried to remove and turn the valve but it's stuck. I don't want to turn too hard because I don't want to possibly loosen and rattle the sections that are located underneath it. One section gave me trouble previously with slight hissing (which we fixed) but I don't want to loosen it.

This is a large valve. I was going to use some Liquid Wrench on the threads where the pressure valve is located in order to dissolve the sealant that's already there. Then clean it and reapply pipe dope.

I was also wondering what specific pipe dope I should use since the valve is located above the water. Most of the pipe dopes are based on oil which would drip into the water. Any suggestions?

So here are my questions:

1. Any tricks on removing the stuck valve? Should I be worried about loosening the sections?
2. Would hammering the union below the valve have any effect on the valve itself? (I'm thinking not.)
3. Specific pipe dope that you like for pressure valves?

Thanks for your help everyone. Community here is great.

nicholas bonham-carter said:

Be careful not to generate an incident such as this:

http://philadelphia.cbslocal.com/2016/01/13/1-injured-phila-elementary-school-evacuated-after-boiler-explodes/

Abracadabra

TeachMeSteam said:

1. Any tricks on removing the stuck valve? Should I be worried about loosening the sections?

Nope. Two wrenches and muscle should do it. I doubt it's more than a 2" relief valve.

TeachMeSteam said:

2. Would hammering the union below the valve have any effect on the valve itself? (I'm thinking not.)

On the valve, I wouldn't. Below the valve, I don't think so. Can't say for sure without seeing what we are talking about.

TeachMeSteam said:

3. Specific pipe dope that you like for pressure valves?

Blue monster tape and pipe dope.

rick in Alaska

I don't know why, but when I can't remove a fitting, or even bolts, I can almost always be able to tighten it. Once it breaks loose, then you can unscrew it. Weird.
I also use monster tape and megaloc.
Rick

MikeSpeed6030

Are you using two wrenches, of the same size, torqued in opposite directions? What size wrenches are you using - at least 18" and maybe 24" for a stuck connection. What size is the valve's threaded connection? DO NOT HAMMER.

If you don't have a pair of good wrenches, buy them or call a plumber. Based on your question about pipe dope, I wonder if getting that valve loose may be a bit outside your experience or tool availability.

bmwpowere36m3

Still hasn't responded to why he's removing it in the first... only to put it back on.

Bigger wrenches and muscle!

RJ_4

When I would run into a valve ,fitting or pipe I could not loosen I would tighten (turn clockwise) always using back up wrench, I think Rick mentioned this, this would work sometimes by breaking rust free at valve threads, also soaking threads overnight with a penetrating oil while boiler is off can help

TeachMeSteam

BMW,

To answer your question, I found the connection beneath the valve was leaking very slightly. So, I just needed to take off and re-dope.

To let everyone know, I finally got it off. It took two 24'' wrenches with 2 people and a bit of Krano. I wanted to use the automatic transmission fluid and acetone mix that people rave about online but didn't have any spare. Also didn't want to mess around with that stuff around a boiler just in case.

I did hammer the connection beneath the valve a bit to shake things up. I love the feeling when it finally comes off. It's like nirvana. But I really hate how long it takes.

bmwpowere36m3 said:

Still hasn't responded to why he's removing it in the first... only to put it back on.



Bigger wrenches and muscle!

TeachMeSteam

Mike,

Sorry, read your post too late. I wouldn't have hammered otherwise. I ended up using two 24''.

I usually just use tape on stuff that I am going to eventually put on and off later like the master and radiator vents on the steam line. But use pro dope on other stuff.

Wasn't sure if I should use something special for the pressure valve. But thanks for the help. Appreciate it.

MikeSpeed6030 said:

Are you using two wrenches, of the same size, torqued in opposite directions? What size wrenches are you using - at least 18" and maybe 24" for a stuck connection. What size is the valve's threaded connection? DO NOT HAMMER.

If you don't have a pair of good wrenches, buy them or call a plumber. Based on your question about pipe dope, I wonder if getting that valve loose may be a bit outside your experience or tool availability.

TeachMeSteam

I only ended up just reading your post now and ended up using tape and the brush on blue. But thanks for the help.

rick in Alaska said:

I don't know why, but when I can't remove a fitting, or even bolts, I can almost always be able to tighten it. Once it breaks loose, then you can unscrew it. Weird.
I also use monster tape and megaloc.
Rick

TeachMeSteam

Abra,

Thanks for the help. Actually helped just to get the assurance from you that there wasn't some special situation going on. Good community here.

Abracadabra said:

TeachMeSteam said:

1. Any tricks on removing the stuck valve? Should I be worried about loosening the sections?

Nope. Two wrenches and muscle should do it. I doubt it's more than a 2" relief valve.

TeachMeSteam said:

2. Would hammering the union below the valve have any effect on the valve itself? (I'm thinking not.)

On the valve, I wouldn't. Below the valve, I don't think so. Can't say for sure without seeing what we are talking about.

TeachMeSteam said:

3. Specific pipe dope that you like for pressure valves?

Blue monster tape and pipe dope.

TeachMeSteam

This was probably the smart thing to do. But we don't always do the smart thing, esp me!

Thanks...

JUGHNE said:

Are you re-installing the same valve or replacing it because it leaks? If re-install have you tested it to be sure it reseals? Even before testing I would locate a new one and check for availability in your area just in case. If your in a city probably no problem, but for someone like me in the outback it might be overnight. And it is getting really cold for one overnight outage.

TeachMeSteam

Thanks for the advice. I hadn't read your comment but I actually tried what you had said and it seemed to work. I also soaked it overnight as well.

I guess great minds think alike?

RJ said:

When I would run into a valve ,fitting or pipe I could not loosen I would tighten (turn clockwise) always using back up wrench, I think Rick mentioned this, this would work sometimes by breaking rust free at valve threads, also soaking threads overnight with a penetrating oil while boiler is off can help