Leak under second floor two-pipe radiator

SteamBoiler

All

We have a two pipe steam system, Weil McLain boiler with in-wall radiators, typically placed under windows. It is an old plaster on wood lath home, we moved in a couple years back.

There looks to be a significant leak directly under one of the 2nd floor radiators; with paint blistering and peeling in the first floor ceiling and also on the wall adjacent to the ceiling. A moisture sensor shows significant wetness on this area.

This exact same ceiling area had peeling paint last winter, and I had thought nothing of it, attributed to just plaster stripping off the ceiling, scraped old paint off and mudded and painted it. But this is a recurrence and with the blistering it was obvious that there was moisture so I used the moisture sensor and the moisture was off the charts. I had not checked moisture last year.

I looked at the radiator itself and there seem to be no signs of moisture under the steam trap. It looks like I may have to get a pro to open up the wall and/or ceiling and check for leaks in the return pipe, maybe somewhere in the joints? Does this make sense? The roof under the 2nd floor window appears fine so it is unlikely that the moisture is from the roof.

I have attached pictures in order:
General radiator area view
Steam trap (looks newer compared to the traps in the other rads)
Ceiling below radiator
Moisture meter off the charts
Moisture meter good reading close to affected area

Thanks in advance.

Jamie Hall

That trap does look newish. I doubt it's the trap itself that's the problem, but it is quite possible that the threaded connections below it were damaged or even just loosened when it was replaced.

SteamBoiler

Jamie Hall said:

That trap does look newish. I doubt it's the trap itself that's the problem, but it is quite possible that the threaded connections below it were damaged or even just loosened when it was replaced.

Thanks for the comment. Since the trap output threads sit over the exposed vertical pipe downstream of it, if that particular junction were problematic that pipe itself would have signs of moisture, wouldn't it? That pipe is bone dry which is leading me to think that the next junction, which is probably in the wall below, might be the issue. This is definitely a trap that is much newer than the others in the home and this particular radiator always gurgles, for what it is worth.

mattmia2

Could be the window leaking too.

SteamBoiler

mattmia2 said:

Could be the window leaking too.

That's a great point and I did check to see if the window is sealed properly but can't say for sure. There is a small single-story addition to the outside of this 2nd floor window - the interior wall that is wet used to be an exterior wall - and the shingles are right below the window so there is a shingle-outer wall junction right below the window. Water from there could be getting into the interior wall. That is something to check after a few days to see if this wet section is getting dryer in the absence of rain.

JUGHNE

Could you cut the floor boards directly under the trap to get a look at the bottom of the 1/2" drop out of the trap.
Maybe a flex borescope to have a look. They are not that much money and handy for a lot of things.

EBEBRATT-Ed

The person that changed the trap may have caused a leak in the ceiling/wall but before I opened that up I would pull the cover off and get in there and look at the radiator.

If you here it is gurgling and the trap has been changed leads me to think there is a problem with the rad.

You could have a leak near the trap dropping down on the ceiling but buy the time you look for water the heat from the rad has dried it up

SteamBoiler

Update: Doesn't look like the leak is from the window or the outer wall-shingles junction. Still suspecting radiator.

@EBEBRATT-Ed I will try to pull the upper cover off. The issue is that the entire radiator cavity seems bone dry!

@JUGHNE Flex borescope is a great idea, Amazon seems to have a few decent inexpensive ones and it looks like a good general tool for a homeowner.

EBEBRATT-Ed

@SteamBoiler

The water could be dripping down while the boiler is steaming and evaporates and dries up around the rad by the time you look at it.

It could be a fitting in the wall but it's worth a look before you tear things apart

mikespipe

Wrap a parer towel around the steam trap. If it gets wet it will show signs of it even if it drys out. But check it when the steam is up for a wet spot also do it to the radiator valve. A packing nut leak is the most common radiator leak. A 1/4 turn usually solves it. Then leave the valve alone 

SteamBoiler

EBEBRATT-Ed said:

@SteamBoiler

The water could be dripping down while the boiler is steaming and evaporates and dries up around the rad by the time you look at it.

It could be a fitting in the wall but it's worth a look before you tear things apart

Absolutely agree making large holes in the wall is the last thing to be done. I will first try to get as much visual inspection as I can, then an endoscope. Going to call in a pro for anything more than that, if only because a pro will likely make more controlled holes in plaster than I can.

SteamBoiler

mikespipe said:

Wrap a parer towel around the steam trap. If it gets wet it will show signs of it even if it drys out. But check it when the steam is up for a wet spot also do it to the radiator valve. A packing nut leak is the most common radiator leak. A 1/4 turn usually solves it. Then leave the valve alone 

Thanks, going to follow @JUGHNE idea and take out both covers and visually inspect; I was looking only at the trap but looking at the valve is also a good idea.

SteamBoiler

@EBEBRATT-Ed @mikespipe

You were both right and when it rains it pours. I took the service cover off and with the rad running there is a steady drip from the radiator inlet valve and a slower drip from the trap side (you can see a drip forming to the right of the trap, above the wet spot on the rad cavity floorboard). I tried to turn the inlet valve but it looks like it hasn't been touched in decades so didn't want to break anything, may hit it with PBBlaster.

SteamBoiler

@EBEBRATT-Ed @mikespipe

Follow up question, I am pretty sure my home warranty would cover replacement of the radiator inlet valve as it is leaking, as long as the replacement doesn't involve cutting walls or molding. Does it seem like the space available would allow such access? Thanks, I am relatively a steam newbie and don't understand if access is needed to the entire cavity for this.

mattmia2

Where is it leaking, is it leaking at the stem or at that union that is part of the valve?

SteamBoiler

mattmia2 said:

Where is it leaking, is it leaking at the stem or at that union that is part of the valve?

At the stem. The trap looks like it is leaking at the union.

mattmia2

There may be a packing nut there that can be tightened or removed and a little bit of string packing shoved in there, but it looks like it is the type with a washer and a spring that compresses the packing so you would have to figure out how that comes apart and add some packing under the washer.

Cleaning it up some would help to see how it works.

mattmia2

Zooming in, it looks like you take off that c clip then the washers and spring come off and you can shove some string packing behind the washer.

SteamBoiler

mattmia2 said:

Zooming in, it looks like you take off that c clip then the washers and spring come off and you can shove some string packing behind the washer.

Thanks, this is a little beyond my expertise as I am afraid of breaking the valve stem and ending up with no heat! So the plan is to try to call this into my home warranty. Looks like the input valve is on a union and should be replaceable, as long as the space between the molding and the floorboards is sufficient to take the valve off... Does this seem doable?

mattmia2

It would be better to repair it than to replace it for a lot of reasons. You will need someone that knows what they are doing for that.

Jamie Hall

The leak at the trap surely looks like it's the union. That is usually repairable rather easily, but not by tightening the union nut. Rather, you need to split the union enough to clean the mating faces -- which may be easier said than done; there isn't much clearance there. And then make sure everything is nicely lined up and reassemble it.

SteamBoiler

@mattmia2 @Jamie Hall

Thanks for your comments. I will make sure whoever gets assigned to fix this by my home warranty tries to repack the input valve; and splits then rejoins the trap at its union.

Jamie Hall

Keep a close eye on whomever you get. Remember that home warranty companies go for the low bid, and you tend to get what you pay for...

SteamBoiler

Jamie Hall said:

Keep a close eye on whomever you get. Remember that home warranty companies go for the low bid, and you tend to get what you pay for...

Fair enough. The contractor that has been assigned the job claimed they had someone experienced with radiator repair so I am going to ask for them. Thanks for the headsup.

The issue is even experienced well reviewed contractors seem to be so iffy. Had one that replaced a dead sump pump and the new one died quickly and he replaced it again. The 3rd one ran non-stop without putting out water and it turns out there was no vent hole and it started working as soon as I drilled one in. Driving me crazy.

mattmia2

There are companies you can hire to make your online reviews whatever you want them to be. Some of the best companies and restaurants have ratings of like 3.5 out of 5.

EBEBRATT-Ed

The trap is an easy fix. Worse comes to worse you replace the trap and the nipple (it comes with the trap)

The supply valve is not so easy. If the supply valve can be repacked that would be good. If not I would saw the pipe to the right of the valve install a new steam rated ball valve and a union. He will have to be creative to do it but it can be done.......by the right person

Long Beach Ed

You need a real plumber to do this job, not some parts-changer. Good luck with a Home Warranty guy. I wouldn't let them into the house. But I guess they work cheap. Don't say you weren't warned.

SteamBoiler

Long Beach Ed said:

You need a real plumber to do this job, not some parts-changer. Good luck with a Home Warranty guy. I wouldn't let them into the house. But I guess they work cheap.

My home warranty company subcons plumbing jobs to plumbers; HVAC jobs to HVAC techs; and electrical jobs to electricians.

Please proceed making supercilious and superficial remarks.

SteamBoiler

EBEBRATT-Ed said:

The trap is an easy fix. Worse comes to worse you replace the trap and the nipple (it comes with the trap) The supply valve is not so easy. If the supply valve can be repacked that would be good. If not I would saw the pipe to the right of the valve install a new steam rated ball valve and a union. He will have to be creative to do it but it can be done.......by the right person

Thanks for the input, will keep that in mind.

Long Beach Ed

SteamBoiler said:

Long Beach Ed said:

You need a real plumber to do this job, not some parts-changer. Good luck with a Home Warranty guy. I wouldn't let them into the house. But I guess they work cheap.

My home warranty company subcons plumbing jobs to plumbers; HVAC jobs to HVAC techs; and electrical jobs to electricians.

Please proceed making supercilious and superficial remarks.

Long Beach Ed

I'm sorry I came off to you as making supercilious and superficial remarks. My intent is to help.

Day in and day out we see the damage done by so-called professionals. At least in the NYC market there may be one of fifty who do acceptable work. My post was intended as a warning to you. If you choose to save money by using home-warranty-selected contractors, beware and watch them carefully. Don't be afraid to throw them out before they ruin your stuff. You have a beautiful place there that shouldn't be hacked up by the low bidder.

We're all here to help. The 40 years of professional engineering experience offered free is probably not supercilious or superficial. I suggested choosing the mechanic on his merits rather than his price. This is always the best and most economical course of action.

SteamBoiler

General update on this situation:

My home warranty company subcontracts to a local HVAC/plumbing company and they sent one of their older professionals. I will be honest when it comes to my steam system I want to see an older person work on it not a younger person. When he saw the boiler he said that the piping was done correctly, I was glad to hear that! He said that he would replace the leaking input radiator valve as it wouldn't be easy to repack it, and since he would have to take the steam trap off, he was going to replace that too. I also showed him 2 return vents that aren't working and are probably causing system imbalance issues so he is going to try to replace those as well. Once the repairs are complete I will post an update.

SteamBoiler

Long Beach Ed said:

I'm sorry I came off to you as making supercilious and superficial remarks. My intent is to help.

Day in and day out we see the damage done by so-called professionals. At least in the NYC market there may be one of fifty who do acceptable work. My post was intended as a warning to you. If you choose to save money by using home-warranty-selected contractors, beware and watch them carefully. Don't be afraid to throw them out before they ruin your stuff. You have a beautiful place there that shouldn't be hacked up by the low bidder.

We're all here to help. The 40 years of professional engineering experience offered free is probably not supercilious or superficial. I suggested choosing the mechanic on his merits rather than his price. This is always the best and most economical course of action.

Please see my recent update just above this message. I apologize for the sharp remarks but your later post did add more color to your original.

I agree that professionals whether subcons of a warranty company or hired independently of a homeowner, are a crap shoot. I hired a well reviewed plumber on my own to install a vanity and the dude shows up without a level or a stud finder. I had to undo and redo everything he did on my own, however this was a great learning experience. I also had a plumber come in and jack up the pressure on my steam system to 4psi to solve a late radiator issue, I promptly gave him a very negative rating to the warranty company and I believe they dropped him.

Your advice regarding not allowing someone ignorant to work on one's house, is incredibly valuable, whether they are independently hired or from a warranty company. As I said in my post above when I saw the older gentleman for my radiator leak come in this morning and first thing he said on seeing my boiler was regarding the good piping, so that gave me some confidence that the guy at least knew what he was doing and had experience with steam systems.

As with anything else, this site has helped me incredibly to educate myself, if it weren't for this site I wouldn't be able to converse with a professional in his jargon and understand what my system is doing.

Practically speaking the good thing about the home warranty is "professionals" can be called in for various issues, they are relatively competent, and usually there the next day. When I was traveling my kitchen sink faucet leaked, my wife called it in and it was replaced the next day, ditto a bathroom faucet. As an individual it is incredibly hard to filter out good professionals from the bad and I do think there is a business model for a well done warranty company. For any work now if you don't already have a steady tradesman you are looking at making 10 calls, 3 call you back and no one shows.

SteamBoiler

Update on this issue: my home warranty company sent out the job to a local HVAC contractor and a plumber came out for inspection about a week ago. I could tell that in general he knew what he was doing around steam systems so I agreed to his recommendation that the input valves and steam traps at the leaky radiator, and the late radiator, be replaced. I also showed him my return vent and main vent that weren't working.

He came out today and replaced the input valves with Apollo ball valves, and the steam traps with Hoffman 17Cs. The leaky steam trap was a Hoffman 17C as well and was the only part of the entire radiator system that had been touched it looked like in the last 50 years. This plumber had a hard time getting all the old bits off and in one case had to sawzall out, from the inside, a pipe section that was threaded into another pipe, without damaging the threads on the outside pipe that he wanted to keep. So this was a job well done. The vents were replaced as well (Hoffman 75s like for like) and the new ones function. I asked him about Gorton vs. Hoffman and in his opinion the Gortons were great on one-pipe systems but he preferred Hoffman on the two-pipes. The one issue that a typical member of this forum would have with him is, he would go up to 3psi on steam cut-out.

After photo below:

EBEBRATT-Ed

Looks like he knew what he was doing. Good job

Long Beach Ed

That's great to see! Looks like a good start of the new year.

SteamBoiler

@Long Beach Ed @EBEBRATT-Ed

Thanks for the comments.

I do note that my plumber put in Apollo ball valves at the radiator inputs and per @Mad Dog_2 over on the "Save the steam" post that isn't a great idea as the Teflon O-ring may melt - I presume under high pressure, when the steam temperature increases. I do have the pressuretrol set to cutting out at 2psi nominal and know it does cut out, will keep an eye on that. We are in northern NJ and this plumber does a lot of radiator work so hoping this won't be a long term issue.

FStephenMasek

The melting point of Teflon is 600 degrees K, which is 620 degrees F... https://collegedunia.com/exams/polytetrafluoroethylene-teflon-chemistry-articleid-1347

SteamBoiler

FStephenMasek said:

The melting point of Teflon is 600 degrees K, which is 620 degrees F... https://collegedunia.com/exams/polytetrafluoroethylene-teflon-chemistry-articleid-1347

Hi, thanks for the response. This particular family of valves are rated to 400F, approx 200C and per the steam-pressure tables steam can get to 180C at 10psi and 200C at 14psi so a working pressuretrol is essential. As I said I do have it set to cut out around 2psi but the idiot 0-15psi gauge has shown it as high as 4psi before cutting out.

Chris_L

@SteamBoiler, I don't think you are reading the table correctly. It gives the steam pressure in Bar, not psi.

10 psi equals about 0.7 Bar which results in a temperature of about 115C or 239 F. Teflon is fine.

SteamBoiler

Chris_L said:

@SteamBoiler, I don't think you are reading the table correctly. It gives the steam pressure in Bar, not psi.

10 psi equals about 0.7 Bar which results in a temperature of about 115C or 239 F. Teflon is fine.

Ugh, I am a dummy. I did not even notice the units on the X axis or on the table. Thanks a ton!

Edit: What I liked about the Apollo ball valve was the low profile. The old gate valve was a pain to remove as it was too tall to get under the molding. The plumber had to cut it out and it would have been impossible to put a new tall steam gate valve in without cutting into the molding and probably the wall.