Need to replace corroded supply to radiator
Here's what I got: a leak in the radiator line for a second floor hydronic rad in our 130-year-old home. Both of the supply and the return pipes look extremely corroded so I plan to replace both of them in one go. They are only corroded in the region immediately below the radiator. There is a 90° turn to the vertical pipe and the vertical pipe looks fine.
I spent the entire weekend reading and researching and got a quick education mostly from this website. It's an incredible resource!
The radiators in my home are column style Roccoco radiators from American Radiator Company. The radiator in question has an EDR of about 60 and it's piped with 1 1/4" black iron pipe. The system appears to me (after my research) to be an old gravity system that was retrofitted with a B&G pump mounted on the return line. I have been oiling the pump every year but that's about all the maintenance I have been doing. The pump connections have surface corrosion. I also have an old expansion (correction: compression) tank that I'm wondering could be water logged? We've only lived in the house for 6 years but I honestly doubt the previous owners put much effort into maintain the heat system. The pressure reduction valve and the backflow prevention valve both look extremely old and have external signs of corrosion. I've got a lot of green corrosion on the surface of fittings on the return lines too. The boiler looks extremely old, it's a Burnham boiler (210,000 BTU, 80% efficient on label).
After all the reading I've done I have come away with a conclusion I have a whole lot of work to do on this system to get it working better and for it to be a long-term heating solution for my home. I'm also convinced my boiler is extremely oversized. I did a calculation based on the method from Green building advisor using previous gas bills and came up with something like 70,000 to 80,000 BTU heating load. Additionally the total EDR for all my hydronic radiators is something like 366 and I have been able to run my heat very comfortably with the boiler set only to 150° all winter, so that would imply a heating load of only about only 40,000 BTU or maybe 55,000 BTU if unraised the temp to 170 degrees.
However the immediate problem I need to solve is the leaking pipes. Right now my plan is to get the necessary tools to remove the corroded supply and return pipes and repipe it all with PEX C or PEX AL PEX. I want to use PEX because these corroded pipes run through the wood floor joists under the second floor, and it would be a huge undertaking to remove the flooring from above so that I can lift the pipe out of the notches in the wood joists. Instead of doing that I have already removed a big chunk of the ceiling underneath to access the pipes because the water ruined the ceiling.
In order to stop the leaking, I turned off the supply gate valve and also the gate valve that is just passed the backflow prevention valve and pressure reduction valve. This stopped the dripping from the corroded pipe. I also turned off the gas to the boiler.
I'm pretty convinced that I can do the plumbing part of the job no problem. But the HVAC part scares me a little bit.
I have a radiator key and went ahead and opened all the bleed valves on the second floor radiators. They all hissed for a while while they sucked in air. And then they stopped.
My plan now is to go into the basement and open up the drain valve connected to the boiler. But I'm not sure if this is a mistake to do this? Because maybe it will drain the expansion tank too and maybe I don't want to do that?
Anyway If it is okay to do that, I'm thinking that I will drain enough water out of the system to get the water out of the corroded horizontal pipe in the floor joists on the second floor, and I will cut it out on one end and remove the cut piece and then replace it with PEX. Then I will get it all squared away and then refill the system.
A major question about this how to determine what diameter of PEX to use. I understand that modern pump systems only need far far smaller pipe diameters than old gravity systems, but if I replace the old gravity piping on one radiator with more modern narrow pipe, I might restrict flow to that radiator. But then again that particular room has always been sweltering in the winter! So maybe reducing the pipe is a good thing? But if so, should I go with a 1-in PEX pipe then? Or should I go with a more reasonably sized 1/2-in?
I'm also thinking about whether I should run a cleaner through the system and then add inhibitor to the system? But I'm not sure if that's the right thing to do. I know the adding fresh water to the system is bad for it. I'm also really worried about the expansion tank and how to handle that. It's a very old tank and after doing all the reading I've done, it seems like I should probably replace it with a newer bladder style tank? One problem with my existing tank is that I cannot find anywhere that there is a Schrader valve. It might be hidden up in the floor joists where I cannot access it.
Anyway, I understand there's a lot here! Sorry if it's too much information.. But I figure more information is better than less. I even have a diagram of all of my loops that I could post but it's probably overkill. It's basically just an old standard gravity system, I think, that was retro fitted with a pump and an expansion tank.
Comments
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If your tank looks like a simple drum tank hung from the basement ceiling, you have a compression tank. There's no Schrader walve on those. If it's not leaking, there's no pressing need to replace it. There's not much to go wrong with them, and they last a really long time.
Compression tanks need draining every year. Just close the valve connecting the tank to the boiler, then open the drain on the tank. You should connect a hose to the drain and run it to a floor drain (easiest) or to a bucket. If they're not drained they can become waterlogged and without some air in the tank, the heated water has no room for expansion.
When the tank is dry, close the drain and open the connection to the boiler. When you open the fill valve, the tank will partially fill, governed by your PRV.
You said you have a Pressure Reducing Valve (PRV) on your feed line. Those do occasionally clog or fail, which may be what caused the leaks in the first place.
Pictures of your system would help.
Trying to squeeze the best out of a Weil-McLain JB-5 running a 1912 1 pipe system.0 -
I'm pretty certain it's a compression tank then. It is mounted horizontally and it is big like I have seen with pictures of compression tanks online. The expansion tanks look much smaller and hang vertically?
And unfortunately there is no valve between the tank and the system. I presume this means I have a bit of a bigger problem to fix?
Here are some photos. The compression tank is connected to the return side. I've also included other photos.
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I'm pretty certain it's a compression tank then. It is mounted horizontally and it is big like I have seen with pictures of compression tanks online. The expansion tanks look much smaller and hang vertically?
Correct. It's a compression tank.
And unfortunately there is no valve between the tank and the system. I presume this means I have a bit of a bigger problem to fix?
Pretty minor problem probably. Can you photograph the whole line showing how the tank is connected to the boiler?
Here's your drain. Spray it with Kroil or PB blaster (penetrating oil) a few times before trying to remove.
Rather than replacing the plug, future maintenance is simplified if you replace it with one of these:
https://www.supplyhouse.com/Bell-Gossett-113041-DT-2-Drain-O-Tank-Air-Charger-8629000-p
Trying to squeeze the best out of a Weil-McLain JB-5 running a 1912 1 pipe system.0 -
Thank you for the reply! I think that I understand how that product works. I watched some videos of people using it and it makes sense.
However in each of those videos, the guy had a valve to stop the entire system from draining into the compression tank.
Here are some pictures of the entire connection from the compression tank to the supply line. I note that in my previous response, I'm mistakenly said it connects to the return line.
The pipe comes out of the compression tank, splits into two pipes and then connects to the two supply lines. The two supply lines come down (these are the lines covered in asbestos in the pictures) and come back together before going into the radiator.
As you can see, there are no valves to stop water coming into the tank (and out of the tank drain) from the rest of the system. :(:(
So if I understand correctly, this means I pretty much have to drain the entire system, from the elevation of the compression tank, up? So only the boiler, and the part of the return and supply lines below the level of the compression tank, will still have water in it... right?
To make this go faster I guess I should go ahead and open up the bleed valves on the first floor radiators as well...?
And thinking about this: until I install a valve between the compression tank and the supply line, I will have to nearly drain the system like this every time I service the compression tank. That seems bad since I know adding fresh water over and over again isn't good...
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Something else I just thought of: there is a union fitting in the horizontal pipe run coming out of the compression tank just before it splits off to the two supply lines. It seems like that would be a good place to take the pipes apart and add a valve…? Should I use a ball valve…?
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As far as the radiator piping goes your correct the water will take the path of least resistance so if you undersize the pex to much you may not get heat in that radiator and will create a balancing issue.
Since it is 1 1/4 now I would use at least 1". You could also use 1 1/4" copper tubing. I am assuming you don't want to use black pipe you could find a plumbing supply that could cut the pipe for you. Big box store can if they have some one who knows how to use the pipe machine correctly.
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Yep. That would be a excellent place to put the valve as long as its between the tank and both pickups from the supplies. A good quality full port ball valve would be fine. The valve would be normally open during operation and only closed to drain the tank.
This one:
Make sure you have a wrench on the fitting and the pipe with a helper so as to not put torque on the ell going into the tank. Some penetraiting oil on the threads would help too. Id leave the long length toward the tank alone and make the changes on the short side.
Seems whoever did the system originally as a gravity system wanted to connect to the tank at the point of highest water temperature to try to direct air coming out of solution into the tank. Pretty smart.
Do it in threaded black pipe with a new union. Buy domestic (Ward or Anvil) for the union, you'll be glad you did.
Trying to squeeze the best out of a Weil-McLain JB-5 running a 1912 1 pipe system.1 -
Thanks guys.
Unfortunately the head of the plug sheared off tonight even after putting on the penetrating oil! I'm going to have to just drill a vertical hole through the center of the plug and cut it out after it has drained, I guess.
Is trying to hold onto this tank really worth it? Seems like I could just replace this with an expansion tank for the same amount of effort since I'm already going to be disconnecting the tank to put on the ball valve... but I've never installed compression tank before so maybe that's harder than it sounds.
The problem is I can't install a run of straight black or copper pipe because it is passing through several floor joists. Unless I do it in a bunch of 22" long or so sections that can fit in each joist bay. That's why I was planning to use PEX since I can direct it into the existing holes in the joists.
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Also if y'all don't mind giving me your opinion: what do you think about running a cleaner through an old system like this ..? Is that a mistake? Will I start to get leaks I didn't have before...?
I'm think about doing that and then putting in fresh water with an inhibitor. Do I add inhibitor to every individual radiator...
If it's a good idea: is there any good resource about how to run a cleaning cycle and put in the inhibitor?
Also: shouldn't I also be thinking about cleaning the boiler too...? I doubt it's been cleaned in a very long time.
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I don't think @EBEBRATT-Ed 's comment was so much about pex as to making sure you use a large enough diameter tube.
Regarding abandoning the compression tank, you'd need a pretty big expansion tank anyway to account for the large volume of water in your system. You may want to try draining it by splitting the union and putting a tee after your isolation valve with a drain valve there. Saves trying to cut out that plug.
Trying to squeeze the best out of a Weil-McLain JB-5 running a 1912 1 pipe system.
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Yes I'll plan to use 1" PEX then.
Gotcha on the tee with drain. The tank would drain only a little more than halfway in that case though, right? Is that not a problem? It needs to fill with air doesn't it?
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Seems like the connection to the system is only a couple of inches from the bottom of the tank. That's plenty. The tank doesn't need to be completely dry, just mostly drained.
Trying to squeeze the best out of a Weil-McLain JB-5 running a 1912 1 pipe system.1 -
Oh duh, haha. Of course you're right. I wasn't paying attention to my own photo was just imagining the drain pipe was in the center.
Awesome it's a good plan. Now to figure out how to drain it at the union without getting water all over the boiler and electronics... I think what I'll do is break open the union and then retighten it, then drain at the boiler and check the union periodically to see when the water drops below that point.
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Good plan.
You'll need a way to introduce air to get things to drain. If the tank is waterlogged you may have to drain the tank through the union. Hopefully not, but be prepared.
Trying to squeeze the best out of a Weil-McLain JB-5 running a 1912 1 pipe system.0 -
I guess it will resist draining from the tank whether it's drained at the union or at the radiator. But once the system water level drops low enough I think the pressure from the tank will make it glug glug and pull air bubbles into the tank slowly.... Doesn't seem like draining at the union would make that happen any faster. Hmm.
It will probably be slow enough that the boiler will finish draining first if I use the boiler drain.
It's kind of a smaller pipe going into that tank too so it's going to be slow. And that going to be a problem even after I add the drain at the union.
I wonder if I could use that same kind of pipette draining product you showed me earlier. It wouldn't work as well since the pipette isn't all the way up in the tank but I could somehow use it to blow air into the tank so it drains easier?
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Definitely try the easier method first. 👍️ The thing about the drain-o-tank (pipette) isn't that it goes to the top of the tank, but that it gives a path to break the partial vacuum that's holding the water in the tank if it's completely filled. To use that product you'd have to remove the plug.
If you'll be draining the tank annually and only have to un-waterlog the tank once, you can slide a piece of 1/4" thinwall hose up through the union to the tank and blow air into it to get things going. If you have a little compressor it's not that hard.
If there's still an air bubble in the tank, none of that's necessary, it'll drain on its own. So try the boiler drain first.
Draining large tanks isn't really fast, regardless.
Trying to squeeze the best out of a Weil-McLain JB-5 running a 1912 1 pipe system.0 -
Yes yes I think this one needed to be replaced…
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It is very unusual for hydronic line to corrode unless the system was leaking with lots of makeup water. If that pipe is bad, I’d expect the rest are as well.
Iron pipe holds up very well in closed systems with no leaks. I recently cut out a section of 1” pipe while installing a shutoff in hydronic system with CI rads in my 96 y/o house. Found little to no corrosion.
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I full agree Excessive oxygen caused that issue. Correct the cause!
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Upside of total re-pipe is all those radiators can be converted to use Thermostic Radiator Valve (TRV) with home run lines back to a manifold using smaller (1/2”?) O2 barrier pex giving you much better control of heat in each area. How many radiators do you have?
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those tanks glug vigorously but will drain just fine all the same. Trick is minimizing the mess. I try to hang a drywall bucket to catch the water if you don’t have a drain spigot.
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The tank drained fine today out of the boiler spigot! Lots of glugging. Probably took an hour.
I fully intend to correct the cause! But I'm scratching my head over this corroded pipe because all the rest of the pipe I cut out along the same line was just fine. Nice thick walls. Zero sign of corrosion.
I have been around to inspect all the radiators. There is zero evidence of any corrosion at any supply/return. However this one had evidence of a problem for years that I just ignored until it started leaking.
See the attached photo where you can see the broken adjustment knob and orange tracks of rusty water on top of white paint. I'm just wondering if somebody used a copper or brass fitting on this pipe, and that that caused the corrosion…? I can't tell because it is covered in paint by the previous owner.
Here also are photos of the rest of the pipe sections I cut out tonight. It is all in great shape as you can see… thick walls. No corrosion.
My gut at this time is this only happened at this one location. But I'd love to understand why.
Anyway I'm definitely going to start taking better care of my system from now on! But I am not sure a full repipe is necessary based on what I'm seeing.
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Oh sorry forgot to answer the question above: currently we have four radiators on the second floor and five on the first floor.
Plan to add four more radiators and two baseboards to the first floor in the medium term future. There's an entire half of the house (5 rooms) that used to be on a separate single pipe steam system (sadly the steam rads I have can't be converted to hydronic since water can't flow across the top of them…), and has not had heat in decades ever since the steam boiler went kaput. It stays in the '50s or so on that side of the house through most of the winter so it's not unbearable to be over there but it's not great. We don't spend a lot of time in that part of the house in the winter and we use space heaters right now when we do. And the kitchen has its own forced air system that is full of mildew, and even worse it's just pure electrical heat (no heat pump!) and so I'm replacing it with a baseboard hydronic system for heat very soon, and mini split for AC (mini split can also help with heat if needed of course). The kitchen addition is the only first-floor South facing room- and with only a single story to boot- so it's the only first floor room that even needs AC in the summer. Entire rest of the first floor stays cool enough.
I am considering further expansion of the hydronic system to two, maybe three more radiators on the second floor in rooms that also used to be on that separate steam system and currently are heated with space heaters. But running supply and return runs to that part of the house is really complicated because the external walls are brick and the internal plaster walls aren't the easiest to cut holes to fish pipe through. So I've been thinking about just doing mini split for that part of the house for both heat and AC.
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possibly could have been from that riser leaking and keeping the outside damp
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It shouldn't be a problem to use a brass fitting on iron pipe. It's been standard for the industry for almost 2 centuries.
Something else must be going on to introduce oxygen in that piece of pipe.
@mattmia2 's explanation is pretty plausible.
Trying to squeeze the best out of a Weil-McLain JB-5 running a 1912 1 pipe system.2 -
That's a great theory I hadn't considered and it is supported by the fact that the return pipe, which passed by the corroded supply pipe location, had a lot of concentrated corrosion on the outside of it (although it was nowhere close to compromised) just at that location. That return pipe and the 90 deg supply fitting were actually in physical contact.
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Question for the forum on this same discussion: is a brass fitting to transition from this 1-1/4" black iron pipe to 1" PEX-B (the biggest I can find) an acceptable solution here? Brass fittings are compatible with black iron? EDIT: I see the answer to this above. Thanks!!
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Your pex has to be oxygen barrier.
I see the B&G 100 in your first pics. 1" should be fine.
Trying to squeeze the best out of a Weil-McLain JB-5 running a 1912 1 pipe system.1 -
Are you leaning towards replacing with pex because you have easy access to full run of the pipe? If not and you’ve confirmed the the remaining pipe to that radiator is good, I’d remove bad pipe back to the next joint and re-pipe from that point back to radiator.
You can pick up new radiator 90 and valve with spuds and unions at supply house. You should consider a TRV.0 -
Has to be something flexible to get into those notched joists. The notches are on top and I ain't pulling up my little girl's bedroom carpet and flooring to access with new iron pipe from above. Ain't nobody got time for that. I already had to pull out the plaster ceiling from below to clean up the leaking mess.
Already bought the PEX B that seems to be the recommendation for closed hydronic heating. Got all the old pipe out in six cuts. Since I wasn't sure of the nature of the problem I already cut out both the supply and the return.
Now I'm waiting for penetrating oil to loosen up the connection at the two fittings. Hoping I can get it to budge later today. I really don't want to have to do more cutting and take it back to the next fitting. Sigh.
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If it is not gravity fed but a pumped setup, you don't need such a big pipe. Even a big rad is fine with a 1/2" pipe but if it might be harder to balance if the feed to the rest are oversized.
1" pex will be a bear to pull through there. If you must go for 1", get barrier PERT pipe since it is more flexible. My guess is 3/4" would work fine as well here.
When you remove both steel feeds, you need to support the radiator to keep it from tipping. I find these ceiling mounts with a piece of threaded rod relatively easy.
Getting the screws in might need a small extension.
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Concur with 3/4 PEX but balancing is a consideration with the large feeds going to other radiators. Installing TRV on all radiators would solve this issue.
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I'm still working on this project. Meanwhile it's starting to get a little BRRRRR outside so I'm motivated to get this done.
Greatly concur that I'd LOVE to put TRVs on all my radiators (currently 9; will eventually be 14 or 15 once I do some future expansion). It will address the pipe diameter issue nicely.
I went to the local supply house this morning and they are 6 weeks out for both a 1 1/4" TRV AND a 1 1/4" valve. They also explained to me something new that I did not know, which is that I will likely have trouble finding a TRV or valve that can connect to the existing male-male piece ("spud"? "nipple"? "bushing"?) coming out of my radiator, which is why these parts come with a new spud/nipple/bushing to replace the old one.
I have also watched videos of people struggling to get their spud/nipple/bushing out of their old radiator- and it does not look fun. I see that people rarely are able to get it out with the spud wrench but have had success with cutting it out, but I understand you have to be really careful not to damage the radiator threads.
Below is a picture of my old valve and a picture of the existing ring for the spud/nipple/bushing (same pictures I posted previously), and here also is a link to the TRV that I believe will work well for this (I can have it by Tuesday if I order it today):
https://www.supplyhouse.com/Honeywell-Home-V110E1028-1-1-4-Angle-Valve-for-High-Capacity-Radiator
I have two questions for you guys:
- Is there any chance in hell that the existing ring on my bushing/nipple/spud will properly connect to the new TRV valve I linked above, thus preventing me from having to replace that part too? If not, is there possibly a different brand of TRV (maybe Danfoss?) that I should order that I will have better luck connecting the existing spud/nipple/bushing on my ancient radiator(s)? Or am I absolutely going to be stuck with replacing the spud/nipple/bushing?
- It looks like the part I linked only comes with the thermostatic valve and I have to order a separate control mechanism. It also looks like these come in versions with an integral sensor or remote sensor:
Integral sensor
Remote sensor
It seems to me that the remote sensor is probably superior. Anything to be aware of here? How/where is it recommended to mount the remote sensor? Next to an exterior wall? Dangling from the ceiling…?
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This is a test comment on this thread. I am having trouble posting my response.
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Wow, no surprise that line leaked,
- No chance you'll find a mate to the existing spud.
- I prefer the integrated sensor unless the radiator has a cover on it. If you install a remote sensor you are limits by the length of the capillary tube from the valve portion → control head. Generally just need to put where its exposed in the room (not inside cabinet of behind sofa).
PS; I have a bunch of the Honeywell TRV installed at my house; work great with the old radiators. I'm sure Danfoss units are good too but I've no direct experience.
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Is there a significant difference in quality between the Honeywell TRV and the far cheaper ones I see on Amazon? And are these TRV caps/actuators universal in size/type? Like for example will these cheaper versions work with the Honeywell valve linked above?
What am I getting for my extra $30 to $40 for the Honeywell version...?
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well, Honeywell will guarantee it will work. 😉
You can test setup without the control head if you like. TRV body will run at 100% without the controller to throttle it based on temp. Then you can come back and add heads where you need to adjust for overheating.
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There are significant differences. Capacitors are not just simply a metal can with some weird stuff inside —the weird stuff is often quite special and carefully selected.
There have been instances — can't find them right now — of cheap off-brand caps failing rather catastrophically in use.
You get what you pay for…
Br. Jamie, osb
Building superintendent/caretaker, 7200 sq. ft. historic house museum with dependencies in New England0 -
Agree with getting what you pay for but: how can the cap cause a leak? All it does is move the pin in the valve up and down right? There's no water in the cap. If I put a high quality valve on there with a cheap cap, I am not understanding how that could cause a leak…
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