Air valve on dry return

acl10

Can you put an air valve on a dry return?

BobC

Air valve

We need more information. Is this single or two pipe steam? Where are the existing main vents?



Some pics of the boiler piping and the mains would help us see what your dealing with.



Bob

acl10

Single pipe system

Single pipe system. The back radiator takes along time to heat up due to water in the dry return that doest move fast enough

BobC

Slow radiator

In a single pipe system it's vital that the main vent be large enough to vent the mains in a couple of minutes so steam will be available to all the radiator feeds quickly; the radiator vents should be able to vent the radiators and their leaders a bit slower but the venting should be adjusted so they all get steam at about the same time. This problem radiator might need a higher capacity vent on it if the steam pipe is much longer than the other radiators. Is there any banging on this radiator or supply pipe?



Make sure the pressure cutout is set to1-1/2 to 2 PSI if not lower, sometimes it's hard to tell on those 30 PSI gauges.



What kind of main vent do you have and is there more than one main? Each main should have an air vent near it's end, ideally 15" back from where the return heads down to become a wet return.



Make sure the radiator return is sloped back towards the boiler so the condensate can find it's way back. Also make sure that radiator is sloped back towards the input valve, use a level in both cases to be sure.



Do you have dry returns coming from each radiator or do most of them just let the condensate flow back through the steam supply leader?



If all the other radiators work ok then this far radiator is telling you that more venting is necessary so the steam can get out there. That assumes everything is sloped correctly. Dry returns don't clog unless something happened to fill them with water which might float any crud down the pipe; steam does a pretty good job of keeping things clean.



Bob