Steamhead please help. Trane Vapor System driving me a little crazy.

JohnNY

@Steamhead et al,
I'm rehabbing a Trane Vapor system that seems to have long ago lost its Direct Return Trap and has a vacuum pump and lots of traps added, and then a boiler feed pump. I know there is too much equipment here but I'm hesitant to remove anything. The system works about 80% well and the last few apartments in the 71-unit building receive just little enough steam to be comfortable. That's why I'm there.


My first question to you is, what is your preference in replacing broken metering (orifice) valves?
The building wants TRVs but I need to manage expectations.
I know I've got failed-to-open traps all over the place because thermal imaging shows more steam in the return than in the supply ¼ way through every cycle in many areas. They're running at 1.5-3 PSI. Clearly, first things first, I've got to get the traps working and get some vapor stats in place.
I've got about a dozen "crossover" traps in the top floor apartments where 3" or 3-½" (!) lines warm the bathrooms.


Again, lots of low hanging fruit here but I'm not happy about the vacuum pump. It's not a very large system and the vacuum pump failed (total loss of containment) years ago, and the system isn't operating all that bad.

Any thoughts so far?

Mike_Sheppard

I probably wouldn't be much help. But man I would love to be able to help on that job. I haven't worked on a steam system in almost a year now and I really miss it.

In your experience, how large of a system do you typically start seeing vacuum pumps on? I have dealt with quite a few large systems in Washington DC that had abandoned vacuum pumps and completely ruined steam systems. I've only ever seen one building with a working vacuum pump, and they had a contractor rip it out and install a feedwater tank instead....

Steamhead

Oh boy, @JohnNY - sounds like a major de-knuckleheading project- and just the man for the job.

I'm sure Trane did make vacuum-pump systems at some point but can't find anything on them quickly. Maybe @Pumpguy would know. However, if it seems to be working semi-properly, it may not have had a vac pump originally. So the usual Vapor fixes apply:

1- Fix the traps. Where crossover traps are used, replace them with Big Mouth crossovers to speed up air venting.

2- Reduce the pressure. Install a Vaporstat to keep the pressure below 1 PSI at the boiler.

3- If the system can run on gravity return, and you don't use a vac pump, lose the boiler-feed pump.

Pics please!

JohnNY

Steamhead said:

the usual Vapor fixes apply

Exactly my process so far, but I'd love to get rid of the expense of the vacuum pump, if unnecessary. Right now the vacuum pump dumps into the boiler feed pump, which is the only place I see a main vent (pipe). The hole in the vacuum pump receiver tank might just be venting the system at the moment. The feed pump sits next to the abandoned old boiler. My pics aren't as inclusive of all the mechanicals as they could have been for our purposes now.
I included a pic of the base of a dripped riser which is typical and repeated about 10 times throughout the building. New drip line traps all over but not a single Y-strainer has been replaced or opened to flush.

JohnNY

EBEBRATT-Ed

You may not know until next winter. If the system was designed for vacuum the return lines will be smaller. Most I have seen could be run without a vacuum pump but each situation is different.

A mostly vertical building versus a lower spread out building are different challenges. You probably need the feed pumps to hold some water storage

JohnNY

@EBEBRATT-Ed Yes. I will keep the feed pump for sure. It's doing a good job of playing middleman between condensate and boiler water level.
I'm looking at 2" and 1-½" returns so I can't say I'm convinced the vacuum pump is original or is needed at all. Again, I'm going to pick at the obvious and see how performance progresses.

JohnNY

For the record, so far, all I've done is look and take measurements in this system. None of the new piping/traps/etc you see are mine.

AMservices

In the pic with the 2 new F&T's. I haven't seen a lot of big vacuum systems, but I dont think those air vent play nice with vacuum pumps.
Air will just be sucked in.

Steamhead

AMservices said:

In the pic with the 2 new F&T's. I haven't seen a lot of big vacuum systems, but I dont think those air vent play nice with vacuum pumps.

Air will just be sucked in.

They don't. Probably were added after the vac pump died.

nicholas bonham-carter

Maybe they are Hoffman 76 vacuum vents?—NBC

tim smith

Is that an old nash Jennings vacuum pump?

ariccio

I'm not a steam pro, just a curious reader. What's the point of the "crossover" traps in the top floor apartments? I am presuming that they're not *intended* to be heat for the bathrooms?

Steamhead

@JohnNY , how did you make out with this?

mattmia2

ariccio said:

I'm not a steam pro, just a curious reader. What's the point of the "crossover" traps in the top floor apartments? I am presuming that they're not *intended* to be heat for the bathrooms?

The section of pipe is a radiator to heat the bathroom, the crossover trap is what vents the air out of the pipe and in to the return where it vents out the return or is pulled out of the return by a vacuum pump, without the crossover trap to let the air out the steam can't get in.

Mad Dog_2

I always try to simplify ANY scewed up system and getting back to basics  I'm with cutting away the likely unnecessary appurtenances & equipment...Do we REALLY need this vacuum pump, feed pump?? Many times the answer is no!. Simple problems like rising steam pressure, failed traps, et cetera are not understood and guys come in and complicate simple problems by adding expensive, intimidating equipment.  In NYC, alot of guys can do a really nice, neat looking, sqaurd away piping job...dont let that confuse you:  Don't ever assume ANYONE that came before you knew what time it was...Look, study, question.....Keep us posted...Mad Dog 🐕 

JohnNY

Steamhead said:

@JohnNY , how did you make out with this?

Sorry for the late reply. Since the job is outside of the boundaries of my Master Plumber's license, I was paid as a consultant on this job and simply provided a checklist of work for their in-house mechanical staff to perform. The bigger buildings like that because it's cheaper for them anyway. They replaced all the passing traps and bypassed the leaking receiver tank and pump. Switched over to one vaporstat operating control and a standard pressuretrol for redundancy, and wa-LAH! I haven't heard a thing. That's usually a good sign. I honestly don't know if anyone got TRVs or not but the sense that I got was the simplest of improvements got them to an acceptable level of happy and they grew tired of spending money after that. The old Point of Diminishing Returns thing. Thanks for asking!

Mad Dog_2

Great News...Mad Dog 🐕