I'm new to steam heat and have a few questions about my home system concerning air vents.

Egawrys

Bought an old home last year with a 2 pipe steam system that appears to have undergone many changes throughout the years. Newer boiler some newer copper pipes (yes I know steam in general should all be iron pipes). And a whole bunch of stuff that doesn't match up with the material Ive been reading. I suspect repairs and modifications have been done on a "whats on hand" basis.
- Nora Advanced Steam Manual
- This website as well as others
- Various engineering, insurance and other governmental agencies.

Last year (1st winter) the heat seemed to work well in that there were no funny noises, smells, and most of the radiators heated up quickly. At least from my perspective as I knew little about steam heat anyway. Only real concerns that developed were 1 radiator that only just barely started to get warm (still the case currently) and an air vent in the basement that started leaking some water (a lot at times actually). Enough so the auto fill put 69 gallons back in in roughly 4 months. More on these two in a bit. I called the local guys with ~20+ years steam experience. Couldn't tell me why the furthest radiator wouldn't get hot and sold me a new Hoffman 75 and scheduled a boiler service for 7 months out and ultimately cancelled on me).

I havent been able to get anyone else out here, seems as soon as I mention steam I get ignored. I'm waiting for a lot of calls back though... Full disclosure, I am one of those informed customers some service providers dont like to deal with. You are working on my stuff and i'm more than happy to give you my money but I will need understand why I'm spending it. There are just too many parts changers in the service industries today.

I have extensive experience in most things mechanical, electrical, electronics, fluid dynamics etc. and have been performing Facility maintenance, automotive, and heavy equipment repairs, technical support and training as a career my entire life. I have a better than homeowner understanding on what I'm doing in a tool box both the one in my garage as well as the one in my head.

Steam is an area I have only enough experience to know I have the right physical tools but not the mental ones...yet! Honestly I'd rather learn to maintain this system myself anyway.

More on the system I have, from the header I have three connections, 2 are mains that are 2" and roughly 26' in length and drop a few inches over the length. The third I wont call a main because it immediately reduces to a 3/4" feed as it leaves the header and splits out to two radiators, makes an upwards pitch leading away from the header to the furthest radiator being the one that doesn't heat up. The feed does not terminate to the condensate return line like the other two do and it does not have an air vent. Of the other two mains only one has an air vent (Hoffman 4A) currently stuck open... and its connected directly to the elbow where the last radiator feed comes out and the main drops into the condensate line (no steam trap here either). The last remaining main terminates to the condensate line with no steam trap and there is no vent on this leg. There's a place where I suspect a vent existed at some point although it would not have been 6" up and 15" back though and neither is the 4A on other main. Back to that leaky Hoffman 75, its actually installed on the condensate side in the middle where the two primary zones come together. It no longer burps water, perhaps in conjunction with the 4A now stuck open.

Of the three connections at the header

Of the end of one of the mains where there should be an air vent?

Of the 4A air vent on one of the mains

at the end of the feeder (basement) to this cold radiator

So on to my point and back to my original 2 issues with some questions.

1) The radiator with little to no heat, there is no vent on the feeder line to this radiator. Could the lack of an air vent on this run be the problem, Since there is no room to add an appropriate air vent at the appropriate height/distance etc... in the basement and I cannot access any of these pipes otherwise, (within the walls) could I add a vent to the radiator itself (these radiators can be either 1 or 2 pipe radiators so I have places to stick one in) to resolve this problem. or do I need to drop this whole run in the basement a bit to make room to properly install an air vent. Currently the header is 24" above the waterline of the boiler and the mains/feed rise another 24" before making a 90* and running all over so there is theoretically room but would require new holes through some rather thick stone foundation walls.

2) I am replacing the stuck 4a with a Hoffman 75 (since I have it) but should I install another on the other main?

3) Is the Hoffman 75 on the condensate side appropriate for this location as some sort of equalizer vent?

4) Most two pipe diagrams I've seen have large steam traps at the end of the mains before dropping to the condensate line. Should there be steam traps in between the steam line and the condensate where they come together at the end of the mains. I've seen some diagrams with and some without but havent been able yet to figure out the difference here.

If you made it here thank you for your patience and in advance for any advice you can offer.

Jamie Hall

A few observations...

The radiator which heats poorly or not at all -- how's the trap on the outlet? And I presume there is a dry return out there which also picks up the radiator which does heat? How's that trap? And how hot -- it at all -- is that return? And does it slope so that it will drain back to the boiler?

I presume you have dry returns? Are there main vents on the dry returns? They need to be there.

On the condensate return lines which drop. So long as they drop below the water line of the boiler, they are not a problem and they don't need traps. However, whatever they drop from probably needs venting.

Don't have much else at the moment...

EBEBRATT-Ed

At least the boiler looks like its piped in the right configuration. The copper is lousy but the copper is not the problem. The header on the boiler may be to small.

Can you post the model # of the boiler?

Can you post some pics of a few radiators?

& more pictures of the system piping around the boiler and in the basement

Egawrys

Jamie Hall said:

A few observations... The radiator which heats poorly or not at all -- how's the trap on the outlet? And I presume there is a dry return out there which also picks up the radiator which does heat? How's that trap? And how hot -- it at all -- is that return? And does it slope so that it will drain back to the boiler? I presume you have dry returns? Are there main vents on the dry returns? They need to be there. On the condensate return lines which drop. So long as they drop below the water line of the boiler, they are not a problem and they don't need traps. However, whatever they drop from probably needs venting. Don't have much else at the moment...

Jamie, I'm not sure what you mean by dry return? I'll try and find some information and get back on this one. I do suspect one or more of the traps at the radiators may be faulty this one in particular. I'm having trouble determining for sure even with a thermal imager, in part because I dont quite know whats normal yet. It seems some may be letting steam bypass them altogether as the pipes get within 20*f of the radiator itself and follow its rise and fall in temp. Others may not be opening or not fully as they are a bit slow to warm and the heat never really makes it to the trap. 9 of them are a Warren Webster O2H and probably greater than 50 years old. I'm currently looking for Tunstall TCWW-2501 replacement capsules but seems no one has any in stock and it may take weeks to months for the manufacturer to make a new batch to fill my order. I dont want to replace 10 complete traps if I can help it, lot of stress on old pipes with little clearance at the floor for pipe wrenches. One is a Barnes and Jones 122(?), can’t find which specific variant to get replacement parts so its getting replaced with a Watts G1 purchased locally. At this point I'd rather get them all cleaned and fitted with new capsules so I can understand what they normally look like on an imager when working.

Appreciate your comments on the main traps and venting, I'll get more vents.

EBEBRATT-Ed said:

At least the boiler looks like its piped in the right configuration. The copper is lousy but the copper is not the problem. The header on the boiler may be to small. Can you post the model # of the boiler? Can you post some pics of a few radiators? & more pictures of the system piping around the boiler and in the basement

Sure thing, Here ya go!

This being the furthest from the Boiler and the one that doesn't get much heat. Irrelevant but the floor here is circa 1750's


Typical


Typical, Floors here original with the house 1815.



Boiler, SlantFin


Tough to get much in one photo...

Egawrys

Ok I think I understand the dry return, however this same return collects a total of 6 radiators just before dropping into the wet return near the boiler and just before the Hartford loop. I still dont know for certain if these traps are ok either though. I'm just going to replace them all with either new capsules or new complete traps, difference of a $500 dollar job and $1000 job but at least I'll keep what hair I have left.

I get that its hard to diagnose this radiator if we dont know if the traps are good or not. Let me get them all replaced and I'll revisit it either way.

Jamie Hall

Several comments.

First, at what pressure is the boiler set to cutoff? I can't make out what the pressuretrol is set at, but it's the standard additive flavour, so the cutin on the scale should be around 0.7 psi. Now, keep in mind that on a two pipe

Second. You don't need an imager or anything else to diagnose a trap, although it's handy (or a cheap IR thermometer). What you are looking for is the temperature difference between the inlet and the outlet, the latter measured as close to the floor as you can get. There are three possibilities. First, both sides are cool or cold, and so is all or most of the radiator. The trap is failed closed. Second, both sides are about the same temperature and very close to steam temperature and the radiator is hot. The trap is failed open. Third case, the outlet is significantly (perhaps 10 degrees) cooler than the inlet. The trap is working.

Now. Obviously the working trap is not a problem, and don't even think about replacing it. If the trap is failed open, however, there is a work around: close the inlet valve part way. This may take some fiddling (and you do need to keep the pressure down for it to work) but what you are looking for is the radiator heating about 80% of the way across when the boiler is working at full song. This does assume that the inlet valve works, but if it does, you have just eliminated the need to repair that trap, or at least removed any urgency from repairing it.

Keep in mind while chasing dubious traps that one trap failed open on a given return may result in other radiators on the same return not heating well.

A failed closed trap can also be "fixed", at least temporarily, if the inlet valve is working. Open it and take the innards out, and then close that inlet valve down just as I suggested above for the failed open trap.

Now on returns. For a two pipe system to work properly, you really have to clearly identify what pipes are steam mains, what pipes are dry returns, and what pipes are or should be wet returns.

Steam mains are obvious enough. You can trace the pipe back to the boiler header without any traps or low spots or anything like that. Dry returns are, perhaps, a little less obvious. They usually parallel the steam mains -- often slightly below them -- and are usually a smaller pipe size (not always). All the radiator returns feed into them, and in turn they also return to the boiler but do not connect with the header.

They are cruelly neglected. They must -- no exceptions -- have generous main venting, usually at or near the boiler, and before they turn down to join a wet return. Without generous main venting on the dry returns, the system will work poorly at best. However, there is a curious thing about those vents: again, if the system is working properly, they will never close. If the radiator traps are working (or the valves are throttled enough!) steam will never get into the dry returns -- just air escaping from the radiators as the steam comes in.

Then there is the question of venting the steam mains. Clearly air must get out of them, too, although it is not as critical as it is for one pipe steam. There are two options. In some systems, there are main vents at or near the ends of the steam mains farthest from the boiler. In others, the steam mains connect to the matching dry returns through a steam trap, called a crossover trap. These don't need vents.

Now wet returns. Condensate will form in the steam mains, and all the condensate from the radiators will travel to the dry returns. That has to get back to the boiler. At any low point in either a dry return or a steam main there must be a vertical drip down to a wet return. They may be at the ends distant from the boiler, they may be right near the boiler -- there may even be intermediate ones, but they have to be there. The wet return to which they drop must be significantly below the boiler water line.

I hope some of this commentary helps.

EBEBRATT-Ed

@Egawrys

In your last post with pictures the 10th pic from the top, the middle supply (small one coming off the steam header) looks like it feeds a tee that has a supply coming out the top of the tee and another pipe coming in the side of the tee. The one coming in the side of the tee is that a supply or a return?

JUGHNE

I have a bucket full of Barnes & Jones cage units #1972, replacements for Webster 1/2" #02 (also 502 & 702).

They were on 02H Warren Webster rad traps.
They have only 3 seasons of use from a retired system that ran at 2 1/2 PSI max.

They were used for drip traps on a down feed system.
The dry return piping had open air vent pipes to show any steam blow by so I feel confident they are good.

......but need a replacement gasket on the bottom where the old seat was.....

The upgrade involves removing the old capsule that is screwed to the cap and removing the seat in the trap. Both easy to do. Reuse the existing cap.

The cap comes off easily with proper socket and impact wrench.

I just took these out as reclaim/salvage as the building is going to demo.

PM me if interested, also have many caps and a few 02H bodies with rad spuds.

You may save my children from throwing them away someday.

dopey27177

I am not one that likes copper pipe on steam.
One major problem to your system is the steam piping is uninsulated. Uninsulated steam piping causes an enormous amount of condensate to form in the piping at the beginning of the heating cycle. Additionally,
Heat that should be going upstairs is wasted in the basement.

As far as steam traps go Barns and Jones may have cages and elements for your traps. The system is really old and all the traps if possible needs to be repaired or replaced.

Wherever you have a drop leg at the end of a steam supply you need a vent valve. In your case you have many vent valves.

With a two pipe steam system you operate at lower steam pressures. Operate the system at .5 psig cut in and 1 psig cut out. As recommended you can choke the steam supply to the radiators by turning down the shut off valves to where on a cold day (20s) the radiator heats 3/4 of the way across the top.

Jake

Egawrys

Folks, still very much a work in progress but wanted to post an update because there has been a lot of great advice given here and I wanted to make sure to see it all through.

I’ve sorted out the traps, and appreciate all the advice here. Once you helped me understand how they are supposed to work it was quite easy. First however I had to replace all 10 radiator valves as the seats and packing were just not existent anymore and I couldn’t actually close off the radiators completely to help diagnose the traps. On the topic of traps There was at least one stuck open for sure and a few where the diaphragms were just heavily corroded and could not have been working properly. These all got replaced with Tunstall capsules. One radiator trap (The Barnes and Jones) I could not even get opened. Even with a 1/2 impact. I used the one new Watts trap I purchased a while back here.

The pressure switch started giving me grief over Christmas Eve, and the vents were letting off steam when the system hit 2 psi. I couldn’t adjust it any lower as it was already set to min .5psi cut in and 1 differential. But it wasn’t tripping until 2.5 psi. I had to manipulate the trip lever and it’s now running 0-1 psi cut in/out. I purchased a vapor stat to replace it and hopefully this will allow more accurate switching. I’ve also started cleaning, painting and insulating the pipes but the painting part will now have to wait. It’s a bit too cold here to leave the system off for extended periods while paint dries so the insulation is going up until it warms up a bit. If I’m being honest I would not have expected this to have made such an improvement and apologize for not heeding the advice sooner. My basement is now a bit colder but I’m thinking this is a good thing because the thermostat is directly above the boiler on the second floor and I think I was heating it through the pine floor rather than from the radiators in the room.

I’ve had to correct some pitch along the way and still need to fix the supply to 1 radiator that was heavily affected by correcting the pitch of one of the mains. I’ll need to cut this pipe back about 3 inches and rethread, I’d rather replace it but the elbow in the floor is not easily accessible and the pipe just won’t unthread. This will be a bit of a project to correct and will likely require a substantial application of brute force and ignorance. For now this radiator remains closed since condensate will absolutely fill this pipe.

 Thank EBEBRATT-Ed said:

@Egawrys In your last post with pictures the 10th pic from the top, the middle supply (small one coming off the steam header) looks like it feeds a tee that has a supply coming out the top of the tee and another pipe coming in the side of the tee. The one coming in the side of the tee is that a supply or a return?

The line from the side of the T is a long run to a radiator in my Bedroom, largest radiator and poorest performing. The one coming out the top of the T is a short run to a radiator directly above it. I’m keeping this one closed as there are 3 in the living room and this one is less than 10 ft from the thermostat.These 2 lines feed upwards from the boiler so there is likely some condensate drain back but both radiators have a trap and drain back separately from this supply line.

I have another question though for the group. I have to finish insulating this pipe. However there are 2 sections of return piping that cross it right against it. I’ll need an inch here of space to properly fit insulation. Would it be better to drop the steam supply line a bit increasing the pitch up and away from the boiler or drop the return significantly and bring them in lower on the drop line to the wet return. I’ve tried to markup the photos to help differentiate between the steam and return lines. It’s a Charlie Foxtrot here I know. The two steam pipes in the one photo are the same ones you asked about @EBEBRATT-Ed. The single steam pipe in the other photo is a continuation of the lower of the two. The return line rests against it in 2 spots before it passes through that stone wall. The steam pipe is already against the bottom of that opening so it would require removing more stonework. Beyond that wall it continues on another 15’ unmolested before going up through the floor.

currently this steam line is 22” above the header which is 24” above the water line. The pipe is currently pitched 1” on 10ft roughly.

JUGHNE

For insulating, if the pipe cross at right angles or nearly so, often a "fish mouth" or notch is cut in one or both pipe covers.

Even if running parallel closely together, the insulation can be trimmed along the length and then the pipes are almost sealed as one. May take a lot of tape. There are rolls of white insulation sealing tape, just like electrical tape, that work well for unusual situations. You do not want to stretch it much at all.

There are some good Utubes for insulation install methods.

I am curious, why the paint?

Egawrys

JUGHNE said:

For insulating, if the pipe cross at right angles or nearly so, often a "fish mouth" or notch is cut in one or both pipe covers. Even if running parallel closely together, the insulation can be trimmed along the length and then the pipes are almost sealed as one. May take a lot of tape. There are rolls of white insulation sealing tape, just like electrical tape, that work well for unusual situations. You do not want to stretch it much at all. There are some good Utubes for insulation install methods. I am curious, why the paint?

So I don’t need to worry much then that the insulation would be thin at best in a couple of small spots. Thank you.

I picked up some of this tape I think you’re talking about. I think it’s called ASJ Facing tape. It’s the same material this fiberglass pipe insulation has as an outer jacket. Foil on the inside with some sort woven reinforcement and white paper on the outside. I figured it would come in handy making my own elbows and covering seams between sections.

As far as the paint, the outer surface of the pipes is mostly covered in surface rust. I wanted to clean this up and paint to prevent further oxidation. I’m using Rustoleum flat high heat paint. Once wrapped in insulation it would be hard to keep moisture, even humidity out of the insulation and I had some concern it would would cause it to potentially become a problem more quickly than I would like.

For now I’ve cut and hung most of the insulation but haven’t sealed it yet. Maybe it’s just OCD but I’d sleep better knowing they’ve been painted.

I can work it in sections, weather permitting from here.

I spend a lot of time at YouTube university. I’ll have a look, thanks for the advice.