How to tell if you have wet steam?

ChrisJ

Are there any common signs when your system is producing wet steam?  Does the water level drop a lot while steaming, or can it stay fairly stable?  The only thing I noticed recently was when I intentionally added four steamaster tablets to a boiler it quickly lost a lot of water and triggered the LWCO.  I'm assuming with wet steam, the same thing happens just in varying amounts.



Its a shame we can't all have a pyrex header eh?  On another thought, if it possible to use a probe type LWCO to detect wet steam?

Steve Nichols

actually

I'm very interested in this topic as well.  If anyone has any "telltale" signs, I'd love to learn.  I think I have wet steam as well as some of my convector vents "burble" as the steam enters them.  I also see a bit of condensation at the top of my sight glass. 

I'll be repiping this summer, but any info would be great!

NY_Hammer

Where from you getting

Steamaster tablets?



I know they were available on amazon but now it's not in stock.





Thanks

ChrisJ

steamaster tablets

Gerry Gill mentioned edelmans plumbing supply in bedford hts ohio having them. Might be a good idea to give them a call and ask.



I still have plenty so really have not gone out of my way to find them. I've also considering trying Rhomar's Boiler Pro 903 in the future.

STEAM DOCTOR

wet steam testing

Got this idea from Lost Art. Close bottom glass gauge valve. Remove that little plug. Install a 1/4" brass nipple, a closed 1/4" ball valve and another 1/4" nipple. Let the boiler run for a while. Open the ball valve and see what comes out. If steam comes out then you know that there is steam in the top part of your boiler. If water comes out then you know that you have water in top part of boiler and hence wet steam.

ChrisJ

Gauge glass

I actually did this recently, though I did it to clean the glass. All I got out was steam.

JStar

Tablets

Sid Harvey's has them in stock in most of our NJ local branches.



As far as testing for wet steam, I would imagine that you can reference the saturated steam temperature at its operating pressure. The higher the temperature (superheated), the drier the steam. I would only predict this to work with a very sensitive thermometer, though.

jumper

no no no

wet steam & dry steam both are saturated. They have the same pressure temperature relationship in a steam table. You need a bomb calorimeter to measure the quality of steam. I don't remember what a bomb calorimeter is or how to use one. But I do remember that that is what to use to measure the quality of steam. Quality has to do with how much liquid is in your steam. I don't know what acceptable quality is for an old heating system. Holohan says drier is better. On the other hand, I suspect that it's the liquid in steam which actually pushes air. I can't see how absolutely dry steam could move air.

JStar

Steam

Pressure difference moves steam/air. The pipes could be full of beans, with a difference in pressure, they'll move.

Hap_Hazzard

How do you know it isn't foaming?

Foaming is the reason a lot of guys are reluctant to add anything to the boiler water. I know Gerry has had really good luck with these, but you guys are on different water systems, or you might have added too much or something.



Can you take about a quart out of the drain valve and put it in a pot on your stove and bring it to a boil and see if you get any foaming?

ChrisJ

Foaming?

Hap,



I don't know that I have any issues, I just asked a general question.

Hap_Hazzard

I'm not trying that!

But you're right. Probably about the most colorful way of putting it I've ever heard.

Hap_Hazzard

I thought you lost your water level.

Didn't you say your LWCO came on after you added the tablets?

ChrisJ

Yes and no.

It wasn't my water it was a friends and that was after intentionally overdosing on the pills. A high level is suppose to help clean out the boiler, but it does cause issues as Gerry pointed out.



4 tablets in a small boiler like my friends IN5 is about 2 or 4 times the dosage you want to use for normal corrosion protection.



As I said earlier, I can close the bottom gauge cock, leave the top open and drain the glass and all I get out is steam.

JStar

Tablets

We've used the tablets on the last handful of jobs. We add about one per section. Boil and drain. Then only add another if the water has completely lost its violet color. We've found it to be very effective at picking up the dirt and oil in the water, but it can cause the same problems as dirty water if left in high concentration. I'd be more likely to use it as a one time kind if thing. Nothing can prevent us from going back to a job for proper skimming.

Hap_Hazzard

I'd still say it's foaming.

How else would adding something to the water cause wet steam? Either you decrease the surface tension, by adding a surfactant or raising the pH, making it foam, or you add a slick of oil to the surface preventing the separation of steam from the surface of the water. They'll both drive water up the pipes. In the case of the oil slick, though, you won't get rid of it by draining the boiler and adding more water.

ChrisJ

tablets

I like it because it keeps my water far cleaner than before. After about 2 months I had a slight film of rust on the lower half of the gauge glass. Water was still mostly clean even during steaming.



Of course, there will be some rust from the rest of the system but the amount in the boiler was greatly reduced. I don't think I'll ever run my boiler without them or some sort of low level water treatment again. I think the most important part there is "low level". Just enough to reduce rusting and corrosion of the block, but not enough to interfere with steaming.

ChrisJ

foaming

Hap,



Yes, four pills cause foaming due to very high PH.



That wasn't my question. My question was how can you tell if you have wet steam. My friends system was an observation, not intended to be part of the main question. I know the system with that much treatment had problems, thats why you don't run it that way.



The question was does a system producing wet steam typically result in the water level dropping substantially in the gauge glass. Or, can you have a pretty stable water line and yet still be producing wet steam?

Bio

Gauge glass

I had my boiler running with the tablets for a several weeks also and I notice the water level was low but not enough to trip LWCO and system was running between 0.2oz and 0.5oz and was happy with it, last week I decided to flush it all out and just have plain water and I saw the water level to be very steady and never went below 1" of NWL when steaming and gauge would stay between 0 and 1oz, to me it looks like having some extra Ph could affect somewhat, but for me the difference is 4oz higher in pressure which I think it cant be to bad

ChrisJ

How many

tablets did you add bio?



You need to make sure you're PH doesn't go too high. One tablet may be more than enough.

Hap_Hazzard

Now that I understand the question...

You need to measure the condensate return relative to the load. You should get, what, about 4 oz. per hour per ft² EDR? I think that's the formula. If you get more, you're getting more than just condensate. That's wet steam.

ChrisJ

Measuring condensate

Does this include return from the equalizer?



Do they make a water meter that is sensitive enough for this?

Hap_Hazzard

A bomb calorimeter?

I think somebody was pulling your leg. A bomb calorimeter is used to measure the heat of combustion of a small sample. I can tell you how it works if you're interested, but it has nothing to do with measuring wet steam.

Hap_Hazzard

Not the equalizer--just the load

Since the header-equalizer is where steam and water get separated, it wouldn't be fair to count what you're removing from the steam. Besides, you're just using the EDR of the radiant load to calculate the return.



They do make meters sensitive enough. One is called a measuring cup.

ChrisJ

Problems

I come up with something like 12.25 gallons per hour for my 392sqft of radiation.

Did I do the math right?



And even so, this would only work if you start measuring after all of the piping is up to temperature. Otherwise, your piping is also consuming some steam.

Bio

One

When I used it to clean my tenants boiler I used more and water disappear and came back like Hot chocolate but yes now I use only 1 on both

ChrisJ

Oil

Make sure your boiler has NO oil in it.

Steamaster + oil = BAD just like most other treatments I think.

Hap_Hazzard

Your math is correct.

12.25 gal. * 128 oz./gal = 1568 oz.

1568 oz. / 392 ft² EDR = 4 oz. / ft² EDR



Yes, you'd need to include radiant losses from piping in the radiant load unless you can somehow separate the condensate. For example, if you could collect the condensate directly from each radiator, you wouldn't need to worry about piping.



I'm not sure how they do it in practice, but I bet some of the pros know--not that it's the kind of thing you get called on to do every other week. To them the causes and effects of wet steam are readily apparent as soon as they take a look at the near boiler piping, the spitting vents and the banging pipes.

Jamie Hall

It's not easy

In the heating business, we always deal in saturated steam.  That is, the temperature of the vapour -- the steam -- is exactly at the boiling point for the pressure.  If the temperature of the steam is raised further, you get superheated steam, but we don't do that.



Wet steam is a mixed phase; there is vapour phase water (steam) in equilibrium for the temperature and pressure with liquid phase water -- which may be in big drops, but may be in small drops as a sort of mist.



Our saturated steam is constantly condensing along the walls of the pipes, but particularly in the radiators.  The real problem with wet steam is that extra water, which tends to come out anywhere there is a change in direction (water droplets don't corner as well as vapour!) and, if you have enough water, you get water hammer...



Then of course there are the weird things which happen to saturated steam when you change the pressure without adding or subtracting heat.  But we won't worry about that... (but it is why reduced port valves are a no-no on steam mains).

ChrisJ

Condensate TDS?

I just tried slowly adding a steamaster tablet to a pot of boiling water by first dissolving it in a bowl and slowly adding it.



I expected it to cause foaming at one point but am not sure of what I am seeing at this point.  I have practically the whole tablet in a tiny pot of water and am not seeing what I would call foaming.



I decided to do more reading and found something I am going to try.  It said return water should be pretty much distilled water.  If the TDS of the returning condensate is high, it indicates something more than just distilled water.  I'm going to take some return water as a sample near the end of a heat cycle and measure the TDS and PH of it.  Afterwards I'm going to add a second tablet to the system and wait a while, then take another measurment.

I expect to see a noticable increase in TDS in the return water as well as increased PH which should indicate wet, or at least wetter steam.



I just took a sample of my return water from the wet return and measured a TDS of 2ppm so right now I'm thinking my steam is pretty good.  Being the system isn't running I wasn't sure if some boiler water could've blended but I guess not.  For comparison my tap water showed 250ppm



Probably my biggest concern at this point is how accurate is my TDS meter.



Any opinions?

nicholas bonham-carter

Auto skimmer

This thread makes me determined to devise an "auto skimmer" piping arrangement for boilers wherein the oils could splash up into the skimming port, and be trapped in a sort of equalizer pipe connected to the return. Once a day for the first month a drain valve at waterline height could be opened to release the trapped oil into a bucket. After the first month, the oil could be drained weekly, and later once a year.

Alternatively,the oil catching piping could be combined with the LWCO, so that draining that would also release the trapped oil.--NBC

ChrisJ

auto wet steam detector thingy

How about a permanent conductivity meter that measures the TDS of return water and warns the user of wet steam when a certain reading is exceeded?

Mark N

Wet Steam

Chris, wet steam can have different causes. It can be caused by poor near boiler piping or poor water quality. One would think if it was being caused by poor piping, the water level would drop causing the LWCO to trip. There would be poor steam distribution, high fuel bills, panting vents and water hammer. If being caused by poor water quality, I think you would see water or condensation in the upper part of the gauge glass maybe even water surging over the top of the gauge glass. Then most likely you would also have poor steam distribution, high fuel bills, tripping off on low water, water hammer and panting vents. If your piping is right and the water quality good I wouldn't even worry about it.

ChrisJ

Panting vents

Hi Mark, thank you for posting.



Before the warm weather came all of my vents were chirping. The Gorton C I have in one room was panting, I guess.



When the warm weather came I skimmed the boiler and added only one steamaster tablet in. Since this I have not heard a single sound from any vents.



The problem is the weather changed as well, so I'm not sure if the cause is cold piping which causes a huge delay in steam to radiators, or lower amount of steamaster, or if I had oil in the water again.



With the chirping and panting, my water level was fairly stable and didn't drop much during steaming. I also did not have any hammering.

Mark N

Chirping Vent?

Chris I have Gorton vents on all of my rads and they are very quiet. A gorton C is a fast vent. I could see it causing the steam velocity in the riser to be to fast causing problems with condensate draining from the rad. One would think there would be less noises the more often the boiler runs because the piping is hotter therefore making less condensate.

I have no knowledge of steamaster tablets and side effects of using them. I use just regular water. The last boiler in my house lasted 75 years so I hoping my current can last for half that.

ChrisJ

Chirpign

Yep, they were all chirping.

Honestly I kind of miss it, it was kinda like a "hey, I'm on!" sound,. not loud but noticeable.





I suspect it was caused by too much treatment, and it also makes me want to buy a more accurate PH tester than this roll of tape I have. Its hard to tell whether its 8, 9, 10, 11 and so on.



For all I know it looks like 9 and its actually 11. I do like the idea of checking TDS of condensate though, and I do want to overdose just to see what I get as a measurement.





I just added a second tablet to the boiler. Its going to take some time for it to mix into the system. I'll update later with my findings including whether or not the TDS in the wet return went up.

Mark N

Obsession

Chris if the piping is right and the water is good and the venting is adequate everything will be fine. Don't obsess and just sit back and enjoy the comfort,

ChrisJ

Can't

What fun would that be Mark?

ChrisJ

What Gortons?

Mark,



I'm sorry if I have asked this previously, but what Gorton's are you using?  I found the #5s chirped the most while 4s are silent and 6s not so much.

Mark N

Gortons

I have Gorton #5's and #6's and 1 C.

jumper

not a bomb calorimeter

Perhaps it's a throttling calorimeter we need to measure steam quality. Need to find the heat content per pound. Decades ago I embarrassed myself by forgetting that temperature & pressure are not sufficient to determine dryness of steam unless it's superheated.