Standpipe on the steam boiler return piping?

Bill_69 · February 26

I can't say I've seen in this in the past, and I certainly can't explain it, but recently I went to a call where the complaint was water "erupting" out of a 1.5" pipe near the boiler. When I arrived, the boiler was already cold and turned off from the day before. The standpipe is installed on the wet return line near the boiler, and is piped up about 5-6' above the return line. Next to this pipe is a pipe that is tapped off the steam header, and directly piped into the return as well (no trap, valve, vent etc. in this line) The return line is then piped behind the boiler, and tees in at the Hartford Loop/equalizer. I feel like the piping is correct as far as dimensions/instructions go.

We started the system, and all was good until the steam header started getting hot. Then you could hear gurgling and some slight banging until that pipe started erupting. It took 10-15 minutes? At this same time, the water line was noted to be lower than normal, but still in the glass. (the operating water level is found to be lower than the tag for "normal" water level as well) and of course the boiler shuts off to take on more water.

Anyway, we did some routine things as it was our first time there. Cleaned the pig tails for both controls, flushed out the bottom of the boiler, and cleaned the LWCO/feeder probe. We let the boiler run, and it never erupted again once hot. The numerous air vents were all working. The water level was also found to be staying a little higher now once warmed up, but still below the normal line. I think this is because the Hartford Loop is piped in a little lower than recommended?

I realize this got long winded now- what is the reason for this standpipe, and what is the reason for the steam line piped down into the return line from the steam header? Also, if the Hartford Loop is piped a little short, can the steam equalizer allow steam down into the return, and up the standpipe?

Maybe if I understand this, I can figure what caused this all of a sudden. I'm told this is a 3rd year install, and this problem is new. I'm not sure I believe it's never happened before, but what do I know.

Thanks.

Mad Dog_2 · February 26

Pictures ....

Big Ed_4 · February 26

There is a pipe on the wet return 6' up open ?

ethicalpaul · February 26

I think this is because the Hartford Loop is piped in a little lower than recommended?

Unlikely. I'd also love to see pictures of this pipe

Bill_69 · February 26

Yes sir. When the customer first explained it to me, I thought he was describing the vent on a condensate pump, but this job is gravity return.

And, for the record I considered installing a pipe cap on this line!

Big Ed_4 · February 26

That is dangerous .. Did someone cut out a old return ?

Bill_69 · February 26

Big Ed, I have no idea. Our first time there. I am trying to make arrangements to get back there and take some pictures. Is capping this off a good idea? Or adding a vacuum breaker there?

Jamie Hall · February 26

Very odd. How high is the top of that geyser above the water line? And what pressure is the boiler showing when it erupts? The line from the header down to the return is at least sort of normal…

mattmia2 · February 26

is this 2 pipe?

Bill_69 · February 26

All,

I'm going back tomorrow for pictures, and then I will post same. And it is a 2-pipe system.

I appreciate the help so far.

Big Ed_4 · February 26

Cap it off

mattmia2 · February 26

i bet it is spewing forth because you have a failed trap or a vaporstat that is letting the pressure get too high. Not sure why it exists in the first place though. Maybe it once connected to some sort of vapor specialty. Are there other signs it is a vapor system or is it just a conventional 2 pipe system?

Bill_69 · February 26

mattmia2, Its just a standard 2-pipe system. As far as the controller shutting it off or not- I am not sure. It is set to 8 oz main scale and the boiler gauge is in psi. So not sure which is right yet. But, the standpipe hasn't erupted in 3 days per the staff there, and the building is heating good (for now)

TMS1980 · February 27

Maybe a false waterline?

neilc · February 27

"Cleaned the #pigtails"

were they bad? and now your controls are controlling? if you're looking for Oz's and they were at all pluggy, , , , ,

no more eruptions? right?

EBEBRATT-Ed · February 27

I agree someone's version of a false waterline

mattmia2 · February 27

https://forum.heatinghelp.com/discussion/comment/1889850#Comment_1889850

oh, to break the syphon so it doesn't syphon the return back in to the boiler?

Bill_69 · February 28

I went back to the job today just to take pictures. (I hope I posted them correctly)

The customer stated that the standpipe hasn't dumped water once since we were there 3 days ago. (I don't take credit for it though!) I still appreciate the opinions. My instinct is to put a cap on this open pipe!

hartford loop.jpg

open standpipe.jpg

return piping flow.jpg

return piping.jpg

water level.jpg

EBEBRATT-Ed · February 28

@DanHolohan

shows a picture of similar open pipe vent. I can't remember which book it was in

ethicalpaul · February 28

It seems like a main was taken out of service or something. I would cap it.

Your water looks oily, has the boiler been skimmed?

mattmia2 · February 28

i would put a vacuum breaker on it

mattmia2 · February 28

looks like a false water line but instead of connecting it to the equalizer they left it open

how old is that system, like 50's? that glazed natco tile looks post wwii to early 60's

ethicalpaul · February 28

https://forum.heatinghelp.com/discussion/comment/1889970#Comment_1889970

it drops to the water line, I think it won’t have much vacuum to break

mattmia2 · February 28

https://forum.heatinghelp.com/discussion/comment/1889973#Comment_1889973

the open pipe is there to keep the water from syphoning down to the water line. if you cap it it can syphon the system water line down to the boiler's water line.

Big Ed_4 · February 28

The equalizer looks detached ??

Bill_69 · February 28

I just realized this by looking at my own pictures. The standpipe is the top of a return line "trap." The trap would've needed a vent for water to carry over, no? Now I'm curious why the trap is piped in at all? Couldn't the return line just be piped down with an elbow to join the return line where it connects to the boiler? Why the trap?

To answer some of the questions- Boiler is 3 years old, it is the 2nd boiler in the building since it was built, and I don't know how old the building is. It looks piped properly to me, and equalizer is intact. (If you mean the top pipe to the hartford tee) To the skimming question- the logs show someone was caring for the flushing, blow downs, etc until the last year when they got a new "staff." I agree the gage glass needs cleaned. But water level is steady while running.