Steam Trap Performance and Repair

easyas123

I recently bought a house with a two pipe steam heating system.

I know for a fact that the none of the steam traps on the radiators have been serviced for at least 40 years, and I honestly would not be surprised if they have never been repaired or replaced since the house was built in 1929. All the traps are Illinois 1/2” 1G’s or 1/2” 1T’s. Two of the 1T’s have failed closed. I believe that many of the other steam traps are suboptimal in performance.

I have two questions at this point.
1) Even if a radiator seems to be functioning adequately, would replacing the very old steam traps likely improve the function of the system? I.e., Do steam traps function more poorly as they age short of failing open or closed? The reason I ask this is because I am leaning toward repairing all the traps, while I have the time and I’m in the groove.

2) I’ve seen posts that Barnes & Jones and Tunstall repair kits are essentially equivalent. However, I see that State Supply sells the original Illinois thermostatic capsules. Does anyone have an opinion how these compare to the Barnes & Jones or Tunstall capsules?

Thanks for your help.

nicholas bonham-carter

Defective traps are either failed open or closed, and can either affect the one radiator they service, when closed, or a group of radiators on the same return, if open.
At least all the traps could be inspected for obvious signs of damage, while you have the time and inclination. As there may be some waiting time to get the new capsules, now would be the time to order new capsules for any of them showing signs of wear.
Measure the EDR of all your radiators, and compare that to the rating plate on the boiler, so you know whether you have the correct size or not. If the boiler has been over-sized, then it will have been short-cycling during its life, putting more miles on the traps.
My gut reaction, then would be to replace them all, so that the opening and closing temperatures would be the same throughout. Don't forget the crossover traps at the ends of the returns.
Finally, install a good low pressure gauge, marked in ounces, and a 16 ounce vaporstat.
There should be some reading material on this site about the function of this system, with some additional advice.--NBC

JohnNY

I've been using an ultrasonic tester for my steam trap evaluations and it eliminates a lot of guessing. You can hear the trap cycle open and closed and it happens far more frequently than I realized. A lot of traps I test are stuck open. That's a good way to mask a problem because the radiator still gets hot. It's down the line, and efficiency in general, that suffers.

JStar

I would go a step further and remove all of the trap elements, install orifice plates and some form of burner staging. Then sit back and welcome yourself to a whole new world of comfort and fuel savings.

ratio

@JStar, are those inlet orifices or outlet/trap orifices? I've read Henry Gifford's paper on inlet orifices, and everything makes sense to me. I recently became responsible for a boiler that hasn't seen much in the way of maintenance (& no TLC) in the last few decades. Inlet orifices seem like they'd solve many of my problems, but I'm suspicious of magic bullets.

PMJ

I would go the direction Jstar recommends with some form of staging first. A 1929 steam system almost definitely has way more radiation installed than is needed. This means radiators never need to be full anyway to adequately heat the place. I maybe need 5-6 actually working traps out of 21 rads in my place(2 pipe 1926) - just on small rads in bathrooms. The rest of the rads never fill up anyway and really don't need a trap at all. Any traps that are failed closed will need to be fixed or just remove the element. Failed open won't be an issue on most of the rads if you slow that boiler down with staging or with some of the special controls you can find discussed on this site. Crank it down/spread it out. Much more comfortable.

JStar

ratio said:

@JStar, are those inlet orifices or outlet/trap orifices? I've read Henry Gifford's paper on inlet orifices, and everything makes sense to me. I recently became responsible for a boiler that hasn't seen much in the way of maintenance (& no TLC) in the last few decades. Inlet orifices seem like they'd solve many of my problems, but I'm suspicious of magic bullets.

Magic is an illusion; steam is very real. Orifice plates and burner staging are time-tested and dead-men approved.

Jamie Hall

I might add that depending on what type of valves are installed on the radiators, you may not need to go to the trouble of installing orifice plates. Hoffman valves, for example, can be easily (well, sometimes easily!) adjusted to serve the same purpose (and were intended to be used that way). That, of course, assumes that you don't have busy fingers in the household who will fiddle them once you have them set...

ratio

Right. I just haven't found a lot of information about inlet orifices. Maybe my google-fu is failing me. Is there a source of pre-drilled plates, or should I just hunt down a sheet of copper? What thickness do I need? I'm currently running at 2 lbs +- a few inches, controlled by a pair of Dwyer pressure switches as seen on The Wall a while ago. Mr. Gifford included a table sized for 2 lbs, and it is most likely the design pressure of the system, so I'm inclined to stay there.

This is a larger system, 3675 sq ft Peerless, used to be a parochial school bldg. Pneumatic controls, an old Paragon system did some kind of unoccupied setback (long since atrophied to inoperation). If everything I read about orifice plates is correct, that's the way to go - but everything I've read corresponds to that one paper.

Regarding staging, it's important that I don't void the listing of the boiler, so I've been thinking hard about that. What I'd like to do is modulate the firing rate based on pressure. I can't see any reason why that wouldn't work. If the original on-off control is still in place, I'd think that Peerless would be fine with it. Maybe I'm worried about nothing.

vaporvac

As @Jamie suggested, it might be worthwhile to identify your inlet valves before going to the trouble of installing orifices. Many old two-pipes had a graduated system that essentially worked as an orifice would, metering the steam based on the edr of the rad. Hoffman, Trane and Dunham are a few that come to mind. You can also get their modern-day equivalent through Mepco? (I'm fuzzy on the brand.)
In essence, that one paper is referencing these sorts of valves. In addition, many two-pipes had orifices installed originally. It's not a new idea, just one worth revisiting, as you seem to agree.

The plates can be bought as blanks or pre-drilled to the specs of each rad. The company that makes them (again, help me out here someone) will help determine that. In any case, a pic of a representative valve would help.

Regarding staging: it's generally controlled by pressure. I can't think why a staged burner would void a warranty. Which Peerless do you have and how does rating compare to the installed EDR? With that size system, staging is the only way to go. Mine is half that and the difference in comfort and economy is amazing. (Caveat: I have twinned boilers, but the result is the same.}

ratio

The inlet valves are a mix of pneumatically actuated (various mfgrs), hand wheels, & a few thermostatics that I've added. The half-dozen or so valves I've replaced hadn't orifices in them, but I hope make a more through check this summer.

This boiler is a Peerless model 211A-08-W/S-I. It's rated at 1176000 btu/hour D.O.E. heating capacity, I=B-R rating is 3675 sq ft or 882000 btu/hour steam.

I'm only concerned about changes to the gas train because it is an integral part of the safeties, & this boiler gets inspected every year by . Any changes would have to get past the inspector, and I'm not sure what would happen if he didn't like them. I can't get in the position of having the City/State/Insurance (or whoever) come in & not like things. That said, I REALLY want to modulate this thing. I feel that I could add a modulating valve to the train (not replacing the current controls, & by clever setpoints have it modulate before the pressuretrol kicks it out) & not have made a significant change to the control scheme.

JUGHNE

I worked on an old system from 1918, it used the 2 pipe "Kelmac Retarder" system of traps. There was some long since gone dry return air eliminator that vented air into the chimney. The only air vents were 2 rad vents added as a last resort.
All the trap guts were gone..empty. The dry return air device was gone, hard piped into wet return at boiler.
The Henry Gifford article looked good for this project. However his chart uses 2 PSI. I found a chart that starts at 2 Ozs and goes up to 2 PSI. (Napier Formula for steam flow through an orifice).

Supply Orifices were installed based on 18 Ozs of supply pressure to give only 80% of CI rad EDR.
The boiler runs at only 6 to 12 on a vaporstat ( I assumed I would have to enlarge some orifices), however the house has adequate heat as the thermal envelope has improved. (also we are done with the fear of the 1918 Spanish Flu Pandemic--windows open at night)
The condensate returns are cool to the touch with the system running.
Orifices were supplied by Tunstall, I ordered all drilled to 1/8" just for easy drilling to my size. There was a surprise that the orifices were ordered by pipe riser/valve sizing. I ended up having 3/4" risers/valve with 1/2" spuds into radiator. Where new 3/4" risers were needed to match new 1/2" valves, I added a union in the vertical riser just below the valve that contained the orifice.
Another item of air venting, it occurred to me that a trap would pass a lot more air than a 1/4" or so orifice. Previously all air on this system had to pass thru traps into the dry return air eliminator. It seemed that the orifice system would slow down the air elimination. So the system end of steam main/drips were vented as if it was a one pipe system. (2 Gorton #2's on each steam main and 1 Gorton #2 on each dry return,---6 total)
It heats fast and quiet, the return vents never get hot and I assume never close.....do I need them or just an open pipe??? But then stuff can happen.

The homeowner will insulate all steam mains before next winter and this may change things. Now the pressure control seldom shuts down the burner.

Boiler EDR and connected Edr are a fairly close match (570).
Customer is happy, his gas bills are almost half of previously and I fell good about the whole situation.

JUGHNE

What happen to Easyas123?? I hope he is reading all this and forming some idea of which way to proceed or maybe just threw his arms up and said what happen to my question.

The case I described was ideal in that the boiler EDR and connected EDR was a close match.

I have a school with similar boiler size that Ratio has.
It has inlet orifices sized for 2 PSI and new traps also.
I wish now (wouda/couda) that I would have undersized the orifices more than recommended. The building envelope has drastically improved since 1955 original design. However the boiler is nearly double capacity of needs.

Question to all: how much can you decrease the fire under a given amount of steel and water and still produce the required amount of steam? If it was still fired by coal you could count the shovels and get a good idea. Actually coal was staged or modulated wasn't it? Big fire to get going and smaller to maintain steam??

Just a note on the orifices; in this school I replaced all orifices (based on Henry's 2 PSI charts..many were oversized) and all traps from 1955. Perhaps redundancy but they are there now.
So the old orifices showed wear after 60 years of being over pressured to 5 PSI. Some even torn open and some looked new. But all old copper orifices seemed thinner than what Tunstall sells now.
So consider no moving parts of inlet orifices or the trap elements that have to function thousands of time per season.

nicholas bonham-carter

Peerless has the Mod-u-Pac staged firing system for the 211a series, so as a factory supplied modification, I doubt any inspector would have a problem with it.
It gives 3 levels of firing, I think, with 2 separate gas valves, controlled by a vaporstat.--NBC

Sailah

easyas123 said:

I know for a fact that the none of the steam traps on the radiators have been serviced for at least 40 years, and I honestly would not be surprised if they have never been repaired or replaced since the house was built in 1929. All the traps are Illinois 1/2” 1G’s or 1/2” 1T’s. Two of the 1T’s have failed closed. I believe that many of the other steam traps are suboptimal in performance.

I have two questions at this point.
1) Even if a radiator seems to be functioning adequately, would replacing the very old steam traps likely improve the function of the system? I.e., Do steam traps function more poorly as they age short of failing open or closed? The reason I ask this is because I am leaning toward repairing all the traps, while I have the time and I’m in the groove.

2) I’ve seen posts that Barnes & Jones and Tunstall repair kits are essentially equivalent. However, I see that State Supply sells the original Illinois thermostatic capsules. Does anyone have an opinion how these compare to the Barnes & Jones or Tunstall capsules?

Thanks for your help.

1) Being that we manufacture steam trap cage units or capsules we tend to recommend scheduled replacement for the simple fact that it's hard to predict failure and if you fix only the broken ones now, another might fail 2 weeks later. The expensive part for a typical customer is the labor, which can be 1-10x the part costs. Since you are doing it yourself, you have only your time to value and part costs.

Cage units typically fail completely, some are designed to fail open, others we fail closed. But it's entirely possibly to have a partial failure from debris getting in between the plug and the seat. Usually when a cage unit fails it's because of metal fatigue from age or water hammer has broken the diaphragm or bellows. When that fails, the steam can no longer flash the "juice" inside the diaphragm, and it no longer moves hence failed.

2) Tunstall and Barnes & Jones both make cage units or what they call capsules. We (Barnes & Jones) factory calibrate every single cage unit so that the "throw" of the plug is the same distance on every cage unit regardless of its application.

We are also unique in that we make a SuperTrap with a bronze bellows, stainless cage, and then we wrap the entire cage unit in a fine stainless mesh screen that helps prevent debris from failing the unit. It's about twice the price of a standard cage unit, but it is designed to last twice as long. For the typical college/university it's highly recommended to install SuperTraps as the labor in large scale replacement projects can get expensive.

In your case we make a SuperTrap for the 1G with a tall cover. We also make a standard cage unit that has a normal height cover. Unfortunately we don't make a SuperTrap for the 1T as it's a pancake style trap and the height we need to install a larger SuperTrap isn't there. We do make a regular cage unit though.

Depending on how many 1T you have it might make sense to swap them out for B&J 122A-ST which have supertraps inside from the factory.

Part numbers:

Illinois 1G
1G on cover- 2818 or 6818 (Supertrap)
1G on body or Watts cover- 2819 or 6819 (SuperTrap)
Both require a new cover

Illinois 1T

Part number 1930
Requires a new cover

Call me at the office if you have any questions

Peter



Supertrap for a 1G vs regular cage unit



Typical pancake style diaphragm



Components of a SuperTrap. Stainless cage, stainless mesh screen, bronze bellows and plug, cover



Two SuperTraps, the left I'm pointing to the factory calibration stake, the right has not been calibrated yet.



Failed-closed bellows wiped out by water hammer

EBEBRATT-Ed

JMHO. You will be playing with orfices forever trying to balance a system that size. The pneumatic controls are there for a reason.

JUGHNE

EBEBRATT-Ed I know where you are coming from with that concern. I was lucky with my guesstimations (so far).

But for the OP to this thread, Easyas123, doing his own work in his own house, he may dance with sizing orifices as needed.

Ratio on the other hand, has a fairly involved project which would take more planning. He has started his own thread on the wall.

jumper

ratio said:

@JStar, are those inlet orifices or outlet/trap orifices? I've read Henry Gifford's paper on inlet orifices, and everything makes sense to me. I recently became responsible for a boiler that hasn't seen much in the way of maintenance (& no TLC) in the last few decades. Inlet orifices seem like they'd solve many of my problems, but I'm suspicious of magic bullets.

Speaking of orifices,inlet orifices (or valves) hopefully limit the steam going into radiator.If insulation and windows have been improved then rad is oversized and all that limited steam will condense,and thermostatic traps are unnecessary.At least I think so.I also think that outlet orifices are a good idea to make the pressure in radiator (again hopefully) higher than in return pipe downstream of outlet orifice. On the other hand I've seen buildings without orifices or traps on radiators work pretty well.

PMJ

If a radiator is properly sized for the room it never needs to fill and doesn't need anything on the outlet side. The valve at the inlet can be used to slow any particular rad down if needed. Most people tend to want the bathroom warmer so I leave the inlet for those wide open, fill them up and stop them off with a working trap.

Systems that run to a pressure cut out point at all are filling rads that don't need to be full for the conditions and create bigger temperature swings in the building. The higher the cutout setting the greater the swing. If you can get your system to run at pressures so low that pressure can't really be used for control you don't need traps at all.