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Condensate pump leaking steam

AK_nyc Member Posts: 3
Hi all, fairly new to steam systems and looking for some insight for a building I am working on.

A bit of context: Commercial office building - 22 stories. Single steam boiler operating at a cut-out pressure of 1.5psi, serving a two-pipe perimeter cast-iron radiator system. Boiler is controlled via a heat-timer. There are pressuretrols installed, but it looks like the modulating pressuretrol controls were overridden a long time ago as its settings don't align with actual operation. Current chief is not sure when/what may be been done, but the boiler operates fairly well so no questions asked to this point. No major issues with heating up the building, if anything some spaces heat up too much or too quickly during low-load days.

The building has complained that they need to manually release steam at the two steam traps found in the attached photos because the low steam pressure does not force the F&Ts open and the system occasionally gets over-pressurized (this didn't make much sense to me). Additionally, I noticed that the one of the condensate pumps was leaking steam (picture attached).

My main questions are: can someone explain to me the condensate piping/steam trap configuration pictured? Also, any suggestions as to what can be causing the pump to leak steam?


    JUGHNE Member Posts: 11,060
    Is that a feeder pump tank or a condensate pump setup?
    Neither should see any steam to them.
    I assume the tank is vented, does any steam come out of the vent pipe?
    nicholas bonham-carter
  • AK_nyc
    AK_nyc Member Posts: 3
    The pumps feed condensate back into the boiler feedwater tank. I have not noticed significant/unusual amounts of steam venting from the tank vent pipe, but this is only based on a handful of observations.
    EBEBRATT-Ed Member Posts: 15,516
    On the traps in the picture make sure the gate valve that bypasses the traps is closed. That's only a bypass when working on the traps.

    Usually what happens is that the traps are not well maintained and this allows steam into the returns. If a few traps are bad you may see steam coming out of the condensate or feed water tank vent.

    On the pumps, the pump seal is leaking. This is normal over a long time but continued pump seal leakage is usually due to overheated condensate or condensate with a bad PH.

    So you probably need water treatment expert and a trap rebuild/replacement program.
  • gennady
    gennady Member Posts: 839
    edited April 2020
    Throw away traps on condensate tank. Get yourself a book on steam heating. Read it. I mean, you took up the task to work on the problem you know nothing about, and instead of educating yourself, you are asking DIYselfer question here. That’s not fair to your clients.
  • retiredguy
    retiredguy Member Posts: 903
    edited April 2020
    I have looked at the pictures and will make a few statements and ask a few questions. Q #1) What return line do those 2 F&T traps serve; is it a drip line off a steam main or is this line the return for the building radiation? If they serve a main steam supply then they are OK but if they are what we call a "master trap" and serve to isolate steam in the return from the building's radiation then they a mistake or a fools solution to a maintenance problem. If those rtaps are a master trap then you will need to service and rebuild all the radiation traps in the building. There are companies that do this or you can do it in-house. Q #2) are there other condensate return lines in addition to the green line with the traps, that is not shown in the pictures. Q #3) why does the "chief" and I am assuming that you mean the chief engineer of the boiler room or building, say he is not sure or does not know about the "when and why" certain boiler operations don't happen. He should know since he is the "chief" and it's his job to know. Now for some statements. That green tank in the picture with the 2 pumps and sight glass is the condensate feed tank and the bare metal tank off to the right I assume is the condensate tank or dump tank. I would buy or make a blank off plate to fit the tank to pump connection so you can remove a pump for rebuild or replacement during normal boiler running season. I would send all the leaking pumps to a rebuild shop or learn how to replace the seals if you so desire. I would fix the boiler's inability to modulate and check all the other operating and safety controls. As to F&T traps, I am not sure what the statement means about the steam pressure being too low to force the traps open since they do not rely on force or pressure to open. The float (F) lifts and passes water when the level in the body rises and the thermostatic (T) allows air to pass through until live steam enters the trap. If these traps are not doing their job then they need to be rebuilt or replaced. I would have an authorized and bonded service company service the boilers at least once a year. They can fix and/or recommend items to be repaired "in-house".
  • rossc1986
    rossc1986 Member Posts: 2
    Take a breath, and slow down. We have all been there we all started somewhere. Buying a booknis a great place to start. Asking the internet is kind of like playing russian roulette, being as you dont know, you arent going to know if you are getting good or bad advice. I was in your situation about 5 years ago when i took over a plant with 3 high pressure steam generators fresh out of my apprenticeship. Dan Holohan has 2 books you are going to want to get. "The Lost Art of Steam Heating" (a red cover) and "The Lost Art of Steam Heating Companion" (a blue cover) both are great books and Mr. Holohan has an amazing way of explaining things that us techs can understand without an engineering degree. Is this building a vacuum return building and if yes do you have vacuum? I like you are pretty green on this but in my limited experiance which was similar to your situation I had a plant with hoses run all over the place from the strainers because they would just blow the strainers whenever there was hammer, it turned out, among the many many many other problems, they were running the recievers in float only and running about 5psi from the reducing stations. I changed to units to vacuum/float and reduced the reducing station pressure to 1.5-3 psi and eliminated ALOT of issues. Do you have more than 1 reciever in your building? In my plant i have multiple recievers which run vacuum and they all pump back to a main surge tank/ condensate receiver that operates as the feed tank, operating as a condensate receiver for the graviry return for the building it is in, the make-up water surge tank for the system and a receiver for all the other tanks to pump to before it is fed t ok a d.a. tank/feedwater preheater before the steam generators. My system is a bit more complex than what you have but it sounds like some of the same issues. As for the pumps leaking steam your return is too hot and your seals are blown, rebuild your pumps or send them in, and check and replace/ rebuild ALL the traps in the building. The bad traps getting fixed will fix MOST of the issues you are having. As for the controls, find an original schematic or print or manual, compair to what you have and put it back the way it should be, replace components that are bad and make sure it works the way it was designed. Also check your pressure gausges themselves, i have run into issues with hammer and stuff where i was chasing my tail looking for a bad trap or valve and it turned out to be a bad guage telling me i had enough pressure when really I didn't have any or had way too much.

    Good luck brother, take a breath, and take it one issue at a time. And dont rely on the internet, for every guy with a sincere answer and the experiences to back it up, there are a hundred guys with bad advise that think they know what to do and are a maricle to not have blown themselves and other up, or guys just wanting to be jerks and give bad advise on purpose.
  • AK_nyc
    AK_nyc Member Posts: 3
    @gennady just looking to get some friendly advice on everything that needs to be investigated, I'm not relaying these responses directly to any clients.

    Thank you to everyone else who posted. This was a lot of help!
  • dopey27177
    dopey27177 Member Posts: 887
    Just a shot at a your problem.
    Are these traps float and thermostatic traps? If they are replace the thermostatic element and check the float assembly and seat.

    These traps need only a 1/4 pound of pressure differential to work .

    At the juncture where the steam traps are it looks like you have a T where two condensate lines connect to each other. If that is the case each condensate line must connect separately to the individual steam trap to prevent steam from crossing into each return.

    Check the bypass isolation valve to see if is open or defective.

    Repair the pumps by replacing the seals as this continued leakage may cause the pumps to freeze when the next heating seasons arrives.