Steam coming out of condensate vent

joshua2002

just fixed a major leak on the system and now steam it’s bellowing out of my condensate vessel vent. Condensate vessel has steam trap.

Jamie Hall

Somewhere out there in the wilds you have a bad (stuck open) trap… or you have serious water line or overpressure problems

ScottSecor

Condensate stations (tanks and pumps) are not designed to "pump" steam. There is not supposed to be a steam trap on the inlet of the condensate tank.

That being said, there is likely one or more bad steam traps in the system that are allowing steam to reach the condensate tank. In other words, not all of the steam traps are "trapping" the steam. Fix the bad traps and you'll lower the condensate temperature.

Long Beach Ed

A trap on the condensate tank was some amateur's attempt to "master trap" the whole system, rather than fix the individual traps that are passing steam. It doesn't work. Since bad traps fill returns with steam, supply delivery is slowed and system balance is very poor.

As ScottSecor says, find the bad traps and fix them. You can often locate them using a thermostatic crayon.

PEvans

My system has drips on the main header and zone valves with F&T traps going directly to the condensate tank. I'm learning that if these are trapping properly the condensate side of the trap should have a noticeably lower temperature that is easily detected with a surface thermometer. I'm not good enough to tell bad traps by listening. I have had these fail open, dumping steam into the condensate tank and the other returns. I have one now that I think is passing steam but I'm reluctant to mess with it during the winter.

The individual radiator traps seem to fail closed closed, and if I can get the traps open I just replace the internals. I have not really put much effort into finding the bad ones.

Pumpguy

I concur with all of the above. If steam is coming out of the condensate pump's receiver tank, then steam is getting in. Pumps don't make steam.

Regarding that master trap, that's a definite NO - NO. While it might stop steam before it gets to the condensate tank, it can really mess up how your system heats the building.

You see, with steam now in the return lines, its at the same pressure as steam in the supply mains. And when fluids (steam is a fluid) are at the same pressure there is no flow. And when steam doesn't flow, it can't carry heat.

You really need to fix the leaking steam traps.

Jamie Hall

I would put the effort —it isn't that much — into finding all the bad traps — radiators, F&Ts, whatever, and fixing them. You might be pleasantly surprised by how much better the system works… you might even find the fuel bill goes down…

JUGHNE

I have worked on traps in several old schools. 80-90 year old systems.

For the end of main drips and such I used the "H" body F&T's, the ones that have 4 ports. The inlet would get a strainer with blow down valve where the 3/8" plug is on the wye strainer. The other inlet would usually get large air vents, usually Gorton 2.

This would speed up the steam to the end of the main, otherwise the air had to go thru the dry return which might have turned into a wet return because of water pockets. Then after that struggle the air would come out of the cond pump vent…perhaps.

The lower openings then are of course the discharge of the trap. On the other port I would install a ball valve for testing to see if any steam was blowing by the F&T trap…….these are all ideas from Dan's books….and I thank him for that.

Then one project had multiple dry returns going to the cond tank. I would add a Tee with open pipe riser up perhaps 24". These were for the most part in the boiler room. This speeds up air venting and would indicate which part of the system had radiator steam traps that were passing steam. This narrows down which section of the building was at fault and kept the steam out of the pump.

One project had overhead/attic steams with down feed supply pipes.

Each drop had a drip pipe trap that was ignored when traps were updated or the rad capped off. These still had 1932 elements inside. These un-doubtly were passing steam into the return.

For this project all rad trap elements were removed and supply valve orifices were installed to deliver only about 60-80% of EDR.

One school had bucket traps that were hiding above a ceiling for at least 20 years.

Those were to be reprimed perhaps every year…….no one knew they were even there.