too much condensate

[Deleted User]

Brad, I have no idea on your questions, the boilers are in the Hershey Plant and we have nothing to do with them. i wrok in Maintenance in the Corporate buildings for Hershey, all our heat is steam, and fed from accross the street in the plant. Thanx for the replies guys, we are figuring at this point the issue is on their side, but they are also askin many questions on ourside as well, its just difficult to know what is going on when you only work on one side of the system

[Deleted User]

condensate issues

we got problems at our facility here in Hershey. basicall the plant has a boiler, that supplies steam to our facility and the various heat exchangers and ahu's. They supply us with 40 PSI steam and we drop it down(300 feet away) to around 10-20PSI. we are getting huge amounts of condensate in our system and the numberous traps cannot take it away fast enough, so we end up loosing portions of our domestic hot water systems because the actual steam lines fill with water. Now the guys at the plant say their Boiler(they have 2 lead and lag) swings so much that it has shutdown and they asked us if we have a load problem, we do not. Any ideas where to start looking?

Mike T., Swampeast MO

Underground steam transmission? If so any way that part of the steam tunnel is filled with water?

[Deleted User]

possible yes. Thats the onlything makin sense to us now, is the tunnel under the road has water in it and when the steam hits that area and cooler temps it condenses. The guys at the plant said they can see some of the tunnel, but can't get to all of it to inspect

Brad White_9

What is your make-up rate?

A couple of things to check for- if the make-up rate is higher than normal (check your TDS and feed water quality in general.

Also when the boilers lead-lag are they isolated with stop-check valves and is there an equalizing mechanism between them on the condensate side? (Surface skim level control for example.)

As a reach, my thinking is that the level controls are calling perhaps when pressure in one boiler suppresses the level in the other, in simple terms. Then when they switch back, the flood occurs.

Is there a surge tank?

Just throwing out a few ideas to chew on but of course need more information.

Mike T., Swampeast MO

I'm not a steam man--let alone industrial steam-- but as long as there's no indication of a large steam leak (e.g. not enough condensate for the steam produced), I'd sure do something to fully inspect the tunnel and at least eliminate the possibility that it's partially submerged.

Brad White_9

It typically is an in versus out scenario

If they are getting too much condensate back at their side, thinking more globally, one would ask how much steam you are using and compare that to what you send back -obviously the quantities have to match.

What if: Someone hooked up a hose to flush a condensate pipe at your end or to prime a trap and forgot to turn it off? Another reach but what else would give back more condensate than you take in in steam?

Absent that and other information, I do not see how it could be at your end.

I do not see a flooded tunnel issue being a factor unless the condensate is under atmospheric or even vacuum pressures combined with open leaks or open submerged vents; otherwise it will not accept water from atmospheric sources. Good theory but lower on my list.

If the issue is flooding at domestic water heaters or anywhere else, it may not be too much condensate so much as a blockage hence too little flow downstream of that. A beaver dam of sorts. Same result, looking at it a different way.

Keep us posted, would you? Fun figuring these things out.

Anna Conda

If the boiler water levels are swinging so badly, I wonder if there's a carryover issue? With a pressure reducing station not too far after, wet steam and vapour could be causing a sort of 'domino' effect. If this is a new issue, something had to have changed. Has insulation been disturbed/removed/replaced? Were new types of traps installed? Seen that, where the wrong traps were installed and were passing only a trickle of condensate. But that bouncing water level makes me want to start right at the beginning, in the boiler mechanics and water chemistry.

Unknown

Think of a flooded tunnel with low steam flow...

as a giant ground source heat exchanger.

Leaks wouldn't need to be a part of it.

Noel

[Deleted User]

I will keep ya's posted!

Brad White_9

Got it!

Good point, Noel. Thanks for that. Definitely a "duh" moment for me...

Christian Egli_2

Tunneling across the street for the chocolate motherlode?

Pressure reducing stations have a nice firewall effect, keeping what's on one side separate from what's on the other, in many ways at least keeping problems confined to one side. But not always, of course...

How is the condensate handled?

What sort of condensate is dripping out in the 40PSI side, just ahead of your pressure station? Lots? Also, how is it handled? Is there a high pressure condensate return line? Is there a recycling scheme to pour the live 40PSI condensate back into the low pressure side where it is revived?

On the low side, what do you do with your own low pressure condensate? Do you pump it into a return main on which neighbors also push in their used juice? Is there a low pressure return?

I'm looking at the condensate lines with a suspicious eye just because it seems such water and steam mixtures in the steam main as you describe should also be a good cause for banging, which doesn't seem obvious here (at least not beyond your troubled extremities).

Idea 1

If we suppose the 40PSI pressure has dropped - and you say the boilers have tripped - then this would be a good reason for the pressure to fall in your steam pipes as well. Pumped condensate lines don't loose pressure, they remain up, and so, for whatever quirk of piping, high pressure condensate is backing up your lines, and through the traps, and filling (not just not draining not fast enough anymore!!!) your steam apparatus.

Lack of vacuum breakers (if applicable to your system) would make things worst.

If there is only one high pressure condensate return line for you to up pump your low condensate into, a faulty pump, a faulty check valve (this is always suspect no. one) could explain your flow reversals without even necessarily having steam pressure problems. Neighboring buildings could be pumping their junk into your clean steam pipes.

Idea 2

Supposing there is only a drop in main steam from 40 to 10-20PSI, and you have a scheme at the pressure reducing station that pours all high side condensate into the low side steam - just because it flashes and it's OK as long as the high side steam is high enough to provide the flashing, supposing this scheme was not built to be foolproof, then, if there are problems on the boiler side such as low pressure and possibly increased condensate - your downstream steam service will take a knock-out punch.

Idea 3

This is the common problem to all home heating systems, perhaps there is a faulty trap somewhere that is messing things up by pressurizing the condensate branch you're on.

This could be a bad trap from high pressure steam to high pressure condensate, it could be from high pressure steam to low pressure condensate (if you have any of these, round them up first), it could also be a plain low pressure steam to low pressure condensate, it could also be two faulty traps... and this is getting freaky.

***

Freaky as in what happens in dark underground tunnels. Flooding a steam main on the outside turns the whole thing into a bath warming device. True enough. This causes increased condensate load within the steam main - which brings all sorts of unplanned problems, ***condensate problems*** - but piping steam under water is not itself the steam stopping wall of brick. A steam pipe just does not have all that much EDR surface, and high pressure steam really packs a lot of concentrated heat. If we were to want to boil away all the underground water and fully consume all the traveling steam within the tunnel, we'd need a whole lot more of radiating surface in square feet than there plainly are.

The entire energy of a boiler house burning rail car loads of coal is what is transiting through those rust covered steam pipes. In spite of the frail and benign appearance it is tremendously impressive stuff. It's not power that goes screeching at the mere sight of a mouse.

Piped in hot water, such district systems use bodacious pipes. The sight of which inspires its own wow factor and we fail to see that they only transport caddy loads of energy. They are intuitively more comprehensible to the mind, likewise, dipping the feet of one such boa pipe into a puddle of water wouldn't worry anyone. There, I just wanted to say that, just because I can't help myself...

Good luck Mike

I don't know if I helped, but for devouring chocolate, I can sure hold up my part.

[Deleted User]

wow that alot, i'll try an answer some what. Traps have all been tested ultrasonically, mainly F&T traps, a few thermostatic. We did have 7 bad traps and are replaced now(we have about 300 total) this building was built in 1929, so everything is pressure. We have numberous pressure powered condensate pumps(sarco)that pump back to the biolers. Most of our condensate problems are not found in the primary side, its after the regulator and on or near the equipment, the wierd thing is, its one peice of equipment today, somwhere else the next day, so its hard to find becuz its everywhere. the distance from the primay to our valve inside the buildin is only 15 feet, then once outside the building its 300 give or take, so when the 40 psi comes into the building here it goes threw a boylestown( very old) bucket trap and another bucket trap for a 15 foot ditance then hits our regulator and goes for hundreds of feet through the various piping in the building at about 20 psi

Christian Egli_2

Words are like chocolate you know.

Is this building simply an office and is the steam used only for radiator heating purposes?

If so, rethinking the 20 PSI thing might be useful. Space heating going on and off at all times works best at near atmospheric pressures. They do, no matter what the supply steam is at. An off radiator is at 0 PSI. Then before steam can go in, the air has to be removed, this happens at atmospheric pressures. Next you try building pressure and problems get worse.

Talking about these problems now at the end of the winter season makes me think you're having severe vacuum induced hiccups in your heating elements because they are shutting down, say, every afternoon. And the steam collapses.

Perhaps unit vacuum breakers are needed.

By the way. How is the air vented from the system. Do you have wide open holes on the condensate collection tanks? If you have plugs there, you've found your problem.

I'm addicted to your stuff. and I could go on further with more ideas.

[Deleted User]

no ma'am. the steam goes into 2 heat exchangers for the building hot water system which consists of fan coils, and Airhandlers, Energy recovery units ect. Then we have another system for domestic hot water, sinks, showers for the fitness center, swimming pool. All heat exchangers, some plate and frame some shell and tube. Anyway the condensate pumps are air powered with 30 PSI, work off of a float not much there, we really think this problem is from the plant.

By the way I eat chocolate all the time here, but man, By the time I'm 50 I'll be huge

ttekushan_3

is it possible

one of the heat exchangers is leaking?

Christian Egli_2

Chocolates are always a good idea

If you get into heated arguments with the boiler people, you'll want to be able to tell them your air pumps are actually pumping. It only take a faulty check valves for them to go flat lined. Check-valve seats are not eternal, but they're an easy change.

Check also that your exchangers all have air vents on top of them. Air vents leaving from the top, possibly best piped with a thermostatic trap and a line to an open drain, so you can see and feel them vent. This will allow best air handling no matter how often heat is called on and off. If you don't have any right now, this would perfectly fit the scenario you described with exchangers shutting down and filling up with water, sucking it up under induced vacuum.

I guess the nicest thing to happen would be for the boiler guys to come and tell you they fixed the problem on their side and to offer you a nice box of chocolates. I melt for chocolate, anytime.

Maybe they're waiting for your box of chocolate to put an end to the surging. It must be nice working there.

Have a nice week

[Deleted User]

Another question. We had put dye in the hot water system to make sure we didn't have a leak in one of our many heat exchangers. i notified the plant people, and they got all upset sayin that dye could interrupt their sensors on the boilers and shut them down. We have used this stuff before, so I call the manufacture of it(Hydro Dynamics) and they told its perfectly safe for that type of system, because it does not have chemicals in it that could cause a problem. Any thoughts guys/gals?

Christian Egli_2

Angling for the big box of chocolates

Dye sounds like a good idea. Pressure testing would work also.

I really don't know whether dies are a problem in no-contact level sensors. Maybe?

A bit of thinking on the subject, and I want to say that since the dye is most likely an organic compound, and considering condensate is somewhat acidic, the color would not last all that long before being eaten away, just like some stone washed jeans used to be discolored.

So, were the exchangers leaking? The boiler side people will want the big - I'm sorry - box.

Steve Ebels_3

My money

Is on the flooded tunnel. Even if only 1/4 of the steam pipe is in contact with the water, that's a huge heat sink. Do you ever notice snow melting on the road in that area while it remains in others? That'd be a good clue.

[Deleted User]

good news

Problem solved!!!!!! what had happened is the return pump accross the street was runnin', but the impeller was slippin on the shaft, so the pump chart, if you were to look at it was about half. So to sum it up, all the condensate going back hit a road block with the pump and backed up and gave us the higher pressures in our lines and excess condensate. Their gages on the pump were bad, they replaced and went uh-oh.......they hooked a chart reader to their system and saw say 10k pounds of steam and only 7 back. good deal, thanx to all for the help, you guys/gals are wonderful, learned alot on this one, Knowledge and experience is key!!!!!!!