Vent-Rite no. 2: Adjustable?

BoBoBoB

Most of our radiators have vent-rite #2 vents on them. Are these adjustable? They have a little metal knob at the bottom, but there are no numbers on it like on the Vent-Rite #1. The knob turns on most of the vents (it seems stuck on a few others), and at the very least seems to be able to stop venting (i.e., it can control whether or not a stays radiator cold).



I see an <a href="http://www.heatinghelp.com/forum-thread/66839/Ventrite-2">old thread</a> that indicates these don't play nice with oil/gas. The vents generally seem to be ok--the radiators get hot and the vents don't leak. What are the symptoms of the problems they cause? Should they be replaced preemptively or only when they fail?



My main venting is thoroughly insufficient right now, if that's relevant. I plan on making that project 1, but I'm curious about these guys since there's no info on them anywhere.



(house is 1 pipe, parallel flow, ~350 edr)

Rod

Vents

Hi- The #2(s) are listed in Gerry Gill's wonderful venting chart as being "obsolete". The chart doesn't indicate whether or not they are adjustable. In general, Ventrite vents are very slow vents which was okay in the days of coal fired boilers as the heat was continuous. After you get some good main vents installed, you might want to try a higher capacity vent on your radiators just to see whether the difference is beneficial to your system. While lots of venting on the mains is beneficial, too much venting on radiators can cause problems.

    According to Gerry's chart the Maid -O- Mist (MOM) #4 is equal in venting capacity to the Ventrite #2. The MOM #5 has 4 times the venting capacity of the #4 and the MOM #6 has 6 times the venting capacity of a #4.  I'm not an MOM fan as the workmanship leaves something to be desired. If you find a size that works better with your system, I'd then switch over to Gorton vents of the same number size as their quality is a lot better.  Using larger capacity radiator vents doesn't necessarily mean the system will work better. I use Ventrite #1(s) on a lot of my radiators and are very happy with them. On the #2 (s) you might try boiling them in white vinegar as this helps clean them out.

- Rod