vacuum steam

shawnp1

I have a problem with a vacuum steam system it has a 53ft and a 53v f&t traps the boiler  was changed around 10 years ago I got called to this job for water spitting out of the return vents.the boiler gets up to pessure and is fine then after 5 minutes after the boiler is off water shoots out of the line vents.I am sure he has a few bad steam traps but never recall ever seeing gorton#1 line vents on a vacuum steam system.this is a residental home he just purchased.I raised the vents and unpluged a blocked return line that ran under the floor and back up again and they had left a tee with a plug,which was blocked solid with scale.Did I inharate a problem?  Or  do I have bad f&t traps any reccomendations would be appreciated  it had been a few years since I worked on vacuum steam .My first assumption was bad f&t traps that opened to  quick which allowed the water to rush back to quickly

Jamie Hall

Just one bad trap

will do a number on you.  Check all the traps -- radiators, crossovers (if it has them), everything.



Are there traps other than traps on the radiators and, perhaps, crossover traps?  If so, why?  Most vapour systems didn't have any other traps (some didn't even have those).  If there are other traps, you may have a double trapped system, and those can cause very strange problems.  If so, where are they?  Can you figure out why they are there?



Check your boiler pressure.  If this is a vapour vacuum system, anything over 8 ounces is going to cause trouble.  It should be regulated with a vaporstat -- pressuretrols just can't get that low.  I'd start with an 8 ounce cutout, and 6 ounce differential, and go from there.  Best to get a low pressure gauge and add it, too, as the newer vaporstats sometimes have calibration problems.



Gorton #1 line vents are fine -- but I'd be happier with #2s.  It's really hard to overvent a vapour system (some of them, in fact, simply vented through an open pipe into the chimney).



I'm puzzled by your description of a return which goes under a floor and then comes back up again.  Not that it's impossible; I've seen them -- but it would be nice to know more about it.  I presume that it's a wet return?



I'll think of more tomorrow morning, maybe...

shawnp1

vacuum steam

actually it  a dry return  system,the one return goes under a walkway into a sub cellar and back up into the return,the steam traps are 17c hoffman I remember from an ol timer to check the trap side with a crayon if it melts the steam is passing.I will use a hvac laser temp gauge the hoffman 53v and 53ft are  where they are suppose to go.Maybe its a combination problem which has been occuring for years.I am not just a parts changer.Change parts then hope one of them work.I never used the gorton #2 in all my years I dont even think my supply house stocks them are they slower?  Its a tricky one that I will stick to fixing it for him.This customer is a mech. engineer.I am not to proud to ask for any reccomendations   thanks

shawnp1

vacuum steam

i forgot to mention the origanal call I got from this customer was the pilot kept going out,it was just repaired by ugi.they changed the thermocouple The real problem was  it has 2 pressure controls which were set way to high and one was wired as a safety.to much pressure off on safety ,hence shutting the gas valve off.These guys for ugi,well I wont bash them.Its a 2 pipe vacuum steam with no condensate pump. Dry return into the hartford loop.One thing I did notice was the vents were not piped 15 inches back like they should be.This system could have been like this from day 1 I dont know its history I raised the vent height anothe 6 inches.I set the main 404 as low as it could go and explained that even though the burners were off the boiler was still creating steam, I can see how the pressure control you recommended would work if the steam traps are working.a lot of contractors here in pa love to crank the pressure controls up when they dont need to

Jamie Hall

The Gorton #2

is a much bigger vent than the #1 -- about four times the air volume passed, as I recall.  Your solution to moving the vents should be fine -- the objective of the exercise is to keep them from getting bashed, if a slug of water comes down the return and hits a bend.



I'm still puzzled by the description of the return which goes under and then up -- how does condensate get out of it?



Pressure is one of those things.  People do love to crank up the pressure (it's a variant on the bigger hammer school of repair).  The real problem there is that if a trap or vent is hit by too much pressure it may be damaged -- or destroyed.  They usually fail open when this has happened.  Most vents have a maximum operating pressure of 2 psi, and a maximum withstand pressure in the range of 5 to 10 psi; most radiator traps (including your 17c's) are the same.  Bigger F&T traps, with floats and all, can take more pressure, but the ones usual in heating systems don't like it much.  As I noted in my first note, vapour systems were intended to operate on less than 8 ounces per square inch.



You can get replacement elements for those traps, though... thank goodness!

shawnp1

vapour steam

I see now,I will change the 404 to a vapour stat and remove the #1  for #2 will start with that I now see the higher steam pressure may be pushing or destroyed the steam traps it may have been like this for years. the one pipe that goes under the floor goes under a door way and allways has water in it.It starts off dry  and the make it a wet probabley couldnt keep it high because you would hit you head on it beacuse its a low basement with a sub basementso if you go into the sub and back up they make it wet its always full of water and it must equalize itself according to the water level.because of the hartford loop.The crazy stuff you see out there>And will set it at what you told me .I thank you very much and appreciate the time you took to help me and will let you know how I make out Until then happy heating!