main vents

steamnut

I continue to have super loud radiator hissing despite a new pressuretrol and was going to work on replacing the main vents next. There are two of them, and I am attaching pictures. Both say : No. 77, Vent-Rite on them. Any suggestions on what would best to replace them will be much appreciated.



I also continue to have a pressure gauge which reads up to 4 when the radiators are hissing. I thought I would also try to replace that to see if it is not accurate? Any suggestions on a good replacement for that is also super appreciated!

Rod

Main Vents & Low Pressure Gauge

Hi -

Main Vents - If you can give us the length and pipe size of your steam mains we can calculate the amount of main venting you need.  According to Gerry Gill’s excellent book on venting, the Vent-Rite #77 @ 2 oz. PSI can vent  0 .190 cubic ft. of air  per minute.  At the same pressure a Gorton #1 vents 0.330 cu ft., A Gorton #2 vents 1.10 cu.ft. And a Hoffman #75 vent 0.500 cu ft. so you can see your  #77s are rather on the small side venting wise.  Both Hoffmans and Gortons are available from Pex Supply   http://www.pexsupply.com/    on the internet.



Pressure Gauge -   The 0 -30 PSI gauge that came with your boiler is next to useless when it comes to reading low pressure. However you need to keep it installed as it is required by either insurance or code. The thing to do is to add a low pressure gauge. A lot of people are using a 0-3 PSI gauge # 33020  from the Gauge Store. http://www.gaugestore.com/prodinfo.asp?number=33020

I’ve attached a photo below of a typical dual gauge setup.



Pressure- If your 0-30 PSI gauge is accurate, you are operating at way too high a pressure. A residential steam system should operate at a 2 PSI maximum and most systems operate at a lower pressure than that.  Here’s a link to a good article that tells why lower pressure is better.

http://www.heatinghelp.com/article/348/Pressure/263/The-Speed-of-Steam



New main vents that have more venting capacity and lowering your maximum operating pressure to below 2 PSI,  should take care of your “ hissing” problem.

- Rod

steamnut

main vents

Hi Rod,



Thank you so much for the info. I will def plan to measure the steam mains and post the results to find what you might suggest. I will also plan to purchase the low pressure gauge. Thank you again for taking the time to write a response and share your wisdom. I really really appreciate the help!

steamnut

main vents cont

Hi Rod,

I still plan to measure the main pipes, and I thought I would get the venting manual for sale on this website.  When I looked back at my other, older thread I noticed you had listed a couple of boiler suppliers to contact for steam heating contractors in Maine.  I called two of them.  One of which came out to the house a month ago and replaced the pressuretrol (which I was not covinced was not functioning), and the issue still exsisted.  I called one today who said over the phone that "you can't have too much pressure because the boiler would turn off" and he would just put a different radiator vent on.  I say all this only because I remembered you had said you also found it very difficult to find a knowledable person in the Maine area.  I mean thank goodness for this wall and the books otherwise I would be thoroughly confused.  Did you end up finding someone you could recommend?  Thank you,

Danielle

Rod

Hissing Vents

Hi Danielle- You seem to be running into the same types did. I finally got frustrated enough that I decided I'd needed to learn something about steam. I do most of my own work and occasionally get someone in to do the odd job but under my direction as to the way i want it done.

Off hand I don't know of anyone who I can recommend to you.  Unfortunately my best contact in the Portland, Al Letillier suddenly died this last October. I've put out a couple of feelers this evening but haven't heard back as yet.

 What is the model number of your new pressuretrol?

- Rod