wet steam

mike jones_2

While we are trouble shooting our wet steam problem,  is there a way to minimize it by having a lot of shorter 1/2 hour boiler cyscles rather than not so many long 1 hour cycles.?



We already put  smaller vents on most radiators to slow down the steam even though it is set for under 1 pound pressure.



In the meanwhile, if we don't keep emptying the water out of the vents of many radiators, they stop working until we dump the water.  No noise or spitting or banging though. 

JK_3

WOW

I am sitting here trying to picture in my mind how the steam and condensate moving through a system could allow water build up in the vents without there being other indicators of a problem. I first thought failed vents but you indicated no spitting and recently changed. Then I thought backpitched rads but that usually brings lots of banging.Mabye more details would help. How long has this been going on? was it gradual? Has something been changed in the system? Hopefully with a little more info someone here can offer some advise

mike jones_2

wet rad vents

agreed, the problem is bad, but has so few symptoms other than vents filling fast with water. 



there is no heat at night unless it is super cold, but all the pipes are insulated. we even drilled holes into the floors and dropped the "gerbil" type insulation into them to insulate around the rad supply pipes. 



could the pipes get so cold at night that they get mad condensate in the am?  if so, everytime someone has no heat u would think they would have this problem right after.

JK_3

More info might help

Has this always been a problem or has something changed in the system that may be causing the problem?

mike jones_2

wet rad vents

the boiler was put in last year.  the old boiler started doing the same thing when it was being run all the time as it was dying.  the new boiler runs more normal periods and is very efficiient, IF the dumb vents get dumped!  we sent smith pics of the header/equalizer and confirmed all pipe dimensions. does this help?  we would like to slow down this water filling while it is so cold out while we trouble shoot if u have any ideas!

JK_3

mabye try ?

I am still thinking about what could be causing the problem and hoping someone else might have some ideas but in the mean time maybe  you could try changing the angle of those vents (if angle vents try short nipples with 90's and straight vents and see if this makes a difference)  just an Idea and might help diagnose whats going on.

mike jones_2

water filling radi vents, but no spitting or banging

that ineresting.  will try on 1 and maybe a tiny street elbow on another, and the worst 1 could enlarge to a small gorton 3/4 straight valve.  perhaps the extra turns or sizes might make the water want to drain back into the radi rather than sit full in the vent.  we tried a cone shape vent which has a little syphon lip but it didn't help, and the size of the orifice doesn't make a notable difference either. must have more to do with the outdoor temp and condensation or maybe the length of the boiler cycles.  we can't get any pressure to read on our new 0-5 guage even on a 1.5 hour cycle.



btw, which way should the mains be pitched in this 1 pipe system?  there r dry returns at the end of each of the 2 mains which drip down to the wet returns and back to the boiler by the hartford loop.  the building has settled over the last 100 years and has lolly columns in the cellar. 



thanks for all ;your help, hopefully someone else will chime in or i will let you know a title for a new thread since this might be old soon!

mel rowe

Wet steam??

Homeowner here with somewhat similar experience with water clogged vents in past.  Mostly with TRV's.  Several Wallies suggested that the problem was likely due to the type of vent used, since they did not have a vacuum breaker.  I ordered a different brand, with built-in vacuum breaker and still had the problem. 



Since buying Dan's book, LAOSH, I have personally done a lot of things to improve my boiler system.  Most changes were needed because the replacement boiler was way oversized to EDR requirements and steam velocity was really high, at approx. 36 ft./sec, even after I added a second 2 inch riser out of boiler.  In desperation, I finally decided to downfire the boiler to better match EDR , and to reduce steam velocity as much as possible.  By current calculations, the velocity is now down to approx. 24 ft/sec.  In conjunction with my previous repiping to add a dropped header with a 3 in manifold, I think that is about as good as I'm going to get with this boiler. 



Not sure if this is the same problem as ours, but the bottom line for me is that since all these changes, I no longer have clogged vents, even with the old TRV's that had been a problem. 



Have you calculated the steam velocity of your new boiler system?      

clammy

wet steam

 Wet steam and what;s the cause besides inproper near boiler piping and hi exit velocity are your mains insulated if not there may be your promblem and of course how old is the boiler and has anyone done a water side cleaning or blown out the bottom of the boiler .I have seen the effets of mud on the botton of the boiler which will slow your rate of steam your boiler produces and the quality of steam your system recieves .Have you checked your near boiler piping with the manafactures specs ,the specs they give you in my experence are a mimiun and i have found going 1 size larger will drastially improve the quality of steam your boiler produces and most of the time promblems with rads not heating properly disappear,no matter what you do it has been my experence that without  the proper near boiler piping you woulld be wasting your time trying to correct the promblem by changing  vents .Also are all your rads properly pitches and are all your mains properly pitched with no sags where condensate could possiblable pool ? peace and good luck clammy

mike jones_2

steam velocity

u certianly did a lot of upgrades, hows your heat bill now? i am sure u read up on downfiring, and think your usage would tell u something of ur efficiency.



1 interesting idea for u since it sounds like u r stuck with the oversize boiler - dan has some interesting stuff on running a hot water rad loop and/or a domestic hot water supply with the large amount of steam - many limitations, but just a thought since u have it.



re = trv vents - here is an old dan h article - if u read the end on p. 3 it says trv does not work well with 1 pipe steam. period.  i will try just 1 or 2 for now for our odd problem, but was surprised that dan said not a good idea.



http://www.masterplumbers.com/plumbviews/2003/thermostatic_radiator_valves3.asp



i am trying to figure out the steam velocity thing - it is interesting, sounds like it is simply the piping size vs. the boiler capacity, but i cant' figure out if the fact that our riser out of the top of the boiler having elbows will effect velocity. 

mike jones_2

wet-steam

Thanks Clammy,



we are insulated, and have properly pitched rads and mains. 

the boiler is 2 years old with the problem of wet vents starting when the old boiler was running all the time since it had a hole at the top until we got the new 1.



we skimmed, blow down weekly, and did a blow down from the bottom drain valve while running.  the bottom drain water release was pretty weak since the standard drain valve is kind of small, but the water was pretty clean, certianly cleaner than the lwco blow down water.



we sent smith the piping photo and they said it looked ok, although the riser has some elbows in it to get the 28in. height before joining with the mains/equalizer config. would elbows effect steam velocity?

mel rowe

Downsizing

Mike, Through the total heating season last year, my gas usage was down slightly over 6% compared to the same period the prior year.  I also checked to see if there was a weather related effect and found that the number of heating degree days had actually gone up by 7 %, which says that the reduction in gas usage was even better than 6 %.