Vacum Steam Boiler Replacement

majkaoil

I have an oil fired steam boiler that has let go and needs replacement. It appears to be a vacuum steam system? that more than likely hasn't worked like designed for years....the quick vent on the bucket trap along with a P404A is telling.
The rads are 2 pipe and untrapped. There is a large bucket trap on the return, but if you look at the pics it appears by-passed and for some time too....
Also there is a second return that goes into the boiler un-trapped but with a check valve...
Here are some pics and my main question is regarding a low water volume boiler into this piping scheme...I think I will end up "owning" all the problems that occur after installation...I could downfire or oversize and downfire....maybe a feed tank?? Help!!! lol...

Gordo

Hard to be absolutely sure with the sideways pictures, but that does not appear to be a "bucket trap" in the traditional sense, but in fact is an air venting device that has a float in it to (more or less) prevent water from squirting out if the pressure gets too high and water stacks up that riser and into the dry return.

The Gorton #1 should be replaced with an even bigger vent (or some say left off entirely) as that point was designed to be one of the few, if not the only place where air was vented from the entire system.

The steam needs to be kept out of dry returns and the overall steam pressure kept very low with a vaporstat pressure control.

On untrapped radiators, "something" somewhere is metering the steam into the radiator or maybe there is something in those innocent-looking radiator ells.

Any names, logos or whatnot on the valves, ells or float-vent?

Gordo

Do a careful radiator sizing and leave the boiler feed tank off.
Gravity works best.

Make sure all the radiator valves work so you have half a chance of properly balancing the system.

Question the owner if they have any experience with the system.

vaporvac

That looks like a Trane Air Eliminator. Can you read any writing on it. Gordo is (of course) correct on the metering on the inlet or outlet. If your system is like mine, it has handles that only open so wide that meter the incoming steam to match the radiation. Could you post pics of representative rads with their inlet valves and see if you can read any names on them?

majkaoil

Awesome...it all is starting to make sense...I do in fact have pictures of the valves on the radiators but on my phone...will post them in the morning but it is starting to make more sense now. I assumed that they we "old" style radiator valves. But I can see clearly now they are metering the steam.
Going to see if I can find any more info on the trap, but it being an air vent so to speak rather than a "trap" answers my question of how the other return went straight in with NO trap... Also the import of dry returns explains the check valves...I'm learning a lot from you guys!!!
Will put the rad pics up tomorrow. Thanks guys!!

majkaoil

So the boiler is going to be a 5 section (546 sqft) I am going to put a vaporstat on it, but realize its going to have to be downfired....
I am worried about short cycling...even downfiring to the manufactures downfiring specs...
Thank again all....

vaporvac

@majkaoil ,I don't understand this solution. From reading your original post it seemed you were replacing your boiler. Why would you deliberately oversize a replacement or am I missing something? I was waiting to see pics of your rads and better ones of the Near Boiler Piping. You have one shot to make this right; it costs less to do it right the 1st time than having to redo it or deal with the ineficiency of an oversized, albeit down-fired boiler. That's fine if you expect to add radiation and install a two-stage gas valve, but you didn't mention thqt. What is your EDR?

I'm pretty sure that's a Trane vacuum system, the Cadillac of steam. You could have the best system out there with a little planning. I know because I did it with the help on this forum.

On another note, being oil-fired, there's really only one boiler to choose: the Burnham Megasteam. it's a 3pass boiler and is the only one with any guarantee again water issues. It's also rated at 86% eff and is no more $ than anything else. Where are you located?

AMservices

If you really want to know more about how that system was originally designed to operate, you should buy Dan Holohan's book "lost art of steam heating".
You have what the most efficient and balanced heating system in its day.
Read up on vapor vacuum steam system.
Take a look at the pic, that should give you a little better idea as to what the bucket is doing.

Sailah

I have original Trane catalogs and their literature. I can post pics of the eliminator tomorrow.

The air eliminator can be rebuilt if you are handy. Main thing is to clean things off and especially the plug/seat interface on the float mechanism. And make sure the float floats. If not I have some that should fit. The air vent can be renewed with many commercial alternatives....

We manufacture all of Tranes steam trap parts so if there are traps we can still make those internals. Cool setup.

Steamhead

If that's a Trane, it's a very early version of their system. This would have had special return elbows with orifices in them, as shown in Lost Art on page 257.

Majkaoil, have you had a chance to disconnect one of the radiators to see what, if anything, is in those return elbows?

Looking forward to the upcoming pics.

vaporvac

@Steamhead , when did Trane first introduce the VaporVacuum system? Mine is 1914, all original. The return elbows I have opened were empty, but the valves have the metering adjustable orifices.

@Sailah , holy cow! Is this lit already in the library here? If not I'd love to see it, especially the Air Eliminator. Mine works well, but I've often wondered if another air vent would speed air removal or if it doesn't matter. It looks like it would be really hard to replace.

Steamhead

Not sure. Most of the Tranes we see here were installed in the 1920s and have traps, also there is a neighborhood built in the 1930s that uses Trane convectors with built-in orifices and no traps.

nicholas bonham-carter

Vaporvac, do you have much back-pressure during the initial venting phase?
If the Trane Air Eliminator has a built in trap to close when steam arrives, then maybe no regular main vent is needed.
As you have two boilers, any way you can stage them would keep steam in the lines when only one would run, would speed up system response.--NBC

vaporvac

@Steamhead , thank. It looks like I have an early version! Do the later models also have the metering valves? I would think having them would eliminate the need for orifices in the return elbow.

@nicholas bonham-carter , I realize now my comment on the air-vent wasn't clear. The air-eliminator is the the main vent per se, but uses a "non-return air valve" as shown in the jpg @AMservices posted. That's to what I was what referring. Mine looks like many of the torpedo shaped vents often shown, not a newer one as @majkaoil shows. I've never found any writing on it and have no idea what it is. I should post a pic. I've just often wondered if a different one would be faster, although it looks like it's attached REALLY well.

I build pressure slowly, but will get to 12-16oz. by the time it goes off if I run both boilers. Are you saying that running only one will vent more air because it runs longer? I'm always trying to get better performance so I welcome any suggestions.

nicholas bonham-carter

Running just one once the air is out will give longer run times, with fewer off times. It's only in the off to on times that the air needs to be chased out like the raccoon from the garbage can!--NBC

Sailah

vaporvac said:

@Steamhead , when did Trane first introduce the VaporVacuum system? Mine is 1914, all original. The return elbows I have opened were empty, but the valves have the metering adjustable orifices.

@Sailah , holy cow! Is this lit already in the library here? If not I'd love to see it, especially the Air Eliminator. Mine works well, but I've often wondered if another air vent would speed air removal or if it doesn't matter. It looks like it would be really hard to replace.

I have the Trane Bulletin 14, with a super snazzy velvet backdrop catalog I have scanned as a B&W PDF. I believe mine is an earlier version based on fonts and typeface. I also have a later edition bulletin 14 and bulletin 20 that covers their pumps.

Hell I have 20 of their catalogs and eveyone elses on my bookshelf. I need an intern to scan all that stuff. Actually I need an intern to scan all of original vellum drawings from every steam trap we've ever made or repaired going back to the early 1900s.

majkaoil

The help was awesome all of you....
We completed the installation and piped the return that went directly into the boiler, into the "air eliminator".
This enabled rads that really never got hot to work as intended.
I was able to tweak a few things here and there and the system is working awesome...of course next winter will tell the tale but I couldn't be happier.
Thanks Guys for all the help!!!

majkaoil

Sailah, If that PDF is available I wouldn't mind a copy!! Thanks...