Radiator vents as riser vents?

Alow

Hi - amateur/homeowner here. Our building has five risers. Three of those risers have obvious venting at the top of the riser on the top floor. Two do not have obvious riser vents. Instead it seems the riser goes straight into the radiator.

Is that typical?

If so, what is the recommended venting strategy for these lines? Vent add if they were risers so they fill up at the same rate as the other lines?

Thanks!

Photos are of the top floor radiators and the riser directly below them

Alow

What kind of looks like an insulated riser on the first photo is just a facet of the wall lit more brightly

dabrakeman

What issues are you having?

Jamie Hall

Riser vents and radiator vents really do two different things. Riser vents are like main vents — only for the riser, of course. What they do is help steam get to the radiator quickly so it starts heating. Radiator vents, on the other hand, control how fast the steam can get into the radiator, and thus can (within limits) control how much heat the radiator will put out.

Now risers are often short and relatively small diameter, so venting them fast is often not required — so vents on the risers are often left off. But in tall buildings or buildings with long risers for some reason, they can be helpful.