Air vent hissing in bathroom

bkselly

Most of my radiators seem to be working fine except for the air vent on the smaller bathroom radiator on the 2nd floor. I can feel the air coming out with my hand over the vent which is something I don't feel from the other radiators, and my main large radiator on the 1st floor does heat up entirely without any vent issues. There is no water spitting out, just hissing

Linking the video of the hissing vent as well (be sure to turn on sound on website): https://imgur.com/dZeRO9k

I read the FAQ on spitting and hissing vents - I do think I have a vent on my main (see photo)

Thanks in advance

Fred

That vent on your Main is nowhere near big enough to be a main vent. It is actually a radiator vent. Also, is it at the end of the main? If not, air on the far side of the vent will have nowhere to go except the radiator vents.

bkselly

I'm not really certain if that is technically the end of the main though I would think so as it is on the opposite end of the room (opposite the boiler) and it only goes up from there. My other radiator in the bedroom on the second floor vents very quietly and heat fills up most of the way making me think there is an issue with this specific vent? I do understand your point regarding the photo showing a radiator vent and not a main, but if there wasn't enough venting on the main, wouldn't all my radiators be hissing (instead of just one of three)?

Fred

@bkselly , not necessarily. Air will escape at the path of least resistance and while that radiator vent may be the loudest, that doesn't mean the other vents aren't also sharing the load, in part for a lack of adequate main venting.