Hissing, But No Heat
Still trying to troubleshoot heating problems in my building…What could be the cause of the problem if some radiators are hissing but are staying ice cold while other radiators are getting warm. What causes hissing without heat? Any ideas?
Still trying to troubleshoot heating problems in my building…What could be the cause of the problem if some radiators are hissing but are staying ice cold while other radiators are getting warm. What causes hissing without heat? Any ideas?
As has been posted here before, a human sacrifice is necessary to get steam heat working properly.
If no humans are willing to sacrifice themselves, then gamble with all of the conflicting information on this and other boards, including my information below.
Best of luck to you.
Do NOT let a contractor come to you and charge you hundreds and hundreds of dollars to simply change the vents. Do a little googling, and you’ll save a fortune.
1. Tilt radiators towards valve by placing a metal object of some sort underneath the other legs (using wood to prop up the radiator will eventually backfire as the wood will compress, and the radiator will be level again, allowing condensate to collect in the radiator. Use metal)
2. Ensure all valves are completely open. Remove the knobs so that no one plays with them thereafter.
3. Clean the boiler.
4. Lower the pressure in the boiler.
5. Insulate those risers with fiberglass.
6. Insulate the basement main pipe that most likely runs the length of the building.
7. Cross fingers.
A hissing steam vent is broken. A cold radiator with a silent vent usually means that the vent is full of water. Replace the hissing air vents with Gorton or Jacobus C or D for large radiators. For a small radiator, a Hoffman #40 is sufficient.
You may wish to check the size if the vents on the rads that are hissing but not getting hot. If the vents are not large enough they will not bleed the cool air from the system before the floor where the thermostat is located gets warm (because it is usually closer to the boiler) and the thermostat shuts the boiler off.
The vent on the rad in the room where the thermo is located should be a #4. The vents farthest from boiler should be a a higher number or even a D. The higher numbers or D vents vent faster, getting steam to the end run before it heats the room where the thermostat is located.
Also, once the radiators are hot, the vents should not hiss. if they are hissing when the are hot, they are not closing all the way; you are releasing steam or hot air which will cause your boiler to run more than it should have to.
All of this assumes we are talking about steam heat. If you have hot water heat with gurgles in the rads, that is air trapped inside; that must be bled off.
Call me if you have any questions.
Steve
http://www.thetinkerswagon.com
Sounds like a problem I had. A plumber came and bled my boiler, then changed the valves and put a piece of wood under each radiator and things were fine after that .He said something about air being trapped.The wood was used to tilt the radiators a bit.
could be a cat locked up in those rads…
gee, I haven’t even had heat on except for those cold days last week or so.
Could be not on long enough for all radiators to get hot because thermostat reaches mark very quickly since been pretty warm anyway.
Sounds like your boiler is not firing long enough to get enough steam to those radiators. I would look at a combination of the end of main vent being plugged up and the boiler possible being oversized.
Check the pressuretrol setting and if it is any more than 2 psi, bring it down to 1-2 psi, that may help.
Good luck and please let us know what happens.
-SteamMan