steam radiator venting

jack fitzgerald

One steam radiator vent opens 2-5 minutes after system shuts down. The others follwo suit. Should this be happening? How long should a steam radiator vent valve
stay closed after the system has shut down? Thanks for any help!

Daniel_3

Vents should stay closed up until the temp drops to below the boiling point of alcohol (which boiling seals the vent shut) so excess air after the burn cycle can vent. The vents should stay open all the time when the system is not entering it's fire up and cool down time. The vents shouldn't be making much of any noise if they are working properly. Sometimes when there is excess air in a rad or riser that vent will make the sound of air rushing out so that the steam can enter in but there shouldn't be excess air in one particular area. There are many pros here that know much more than I do but I've learned a small amount about venting to know that unless there is a problem with the balancing or vents themselves then the vents shouldn't be making noise at all. My system isn't perfectly balanced so I do get air pockets once in a while and you'll here the air rushing out of that radiator ever so quietly when the boiler begins to create pressure. All your rads are venting a quantity of air after the cool down. My question is "Is the noise of air rushing loud?" It seems so given you state that they open and close. If the air sound is loud maybe your pressure is set too high and the air is kept in the system because the steam is being kept at bay from entering the rads fast enough. If this is the case maybe set your pressure down lower to keep the steam moving faster. Well this is my two cents and it may need the correct change