main venting

steampunk_2

i have a 2 inch main that is 22 feet long.  for a main vent is one Gorton #2 enough or do i need more?

thanks guys

ChrisJ

More than enough

I would use two Gorton #1's.  So one #2 far more than enough.

Steamhead

I agree

Two Gorton #1 vents should be plenty. Is this the only steam main in the system? 

steampunk_2

main vents

yes sir thats the only main in the system,  would you use the 2 #1's or a single #2?

Rod

Venting capacity

Hi - A  single Gorton #2 has the venting capacity of three plus  Gorton #1(s) so you fine in that respect.  Extra venting capacity creates no problems and actually can be beneficial. Not having enough venting capacity is very detrimental.

- Rod

ChrisJ

Same boat

I am in a similar situation with one of my mains and decided to go with two #1's rather than a #2.  The reason was clearence as well as my beleif is if one out of two #1's fails I can replace it for $20 rather than $55 for a #2.

steampunk_2

main venting

thanks to everyone for all the feedback.  think i'll go with the two smaller as opposed to the single larger because of the failure/replacement considreation that was raised.  i've had to replace several hoffman 4A's and two hoffman 75's that refused to close and they were all fairly new units.  tried boiling them in vinegar and they worked for a little while but then got stuck open again.  just out of curiousity, anyone knew what  the venting rate for a 4A?. 

thanks again to all.

steampunk_2

main venting

thanks to everyone for all the feedback.  think i'll go with the two smaller as opposed to the single larger because of the failure/replacement considreation that was raised.  i've had to replace several hoffman 4A's and two hoffman 75's that refused to close and they were all fairly new units.  tried boiling them in vinegar and they worked for a little while but then got stuck open again.  just out of curiousity, anyone knew what  the venting rate for a 4A?. 

thanks again to all.

ChrisJ

4A

The 4A's vent rate is .13cfm if memory serves.  Its less than half of a Gorton #1.  Unfortunately I learned this a bit late and ended up with two 4A's sitting on the shelf. 

Rod

Venting Capacity

Hi - Using the figures in Gerry Gill's and Steve Pajek's very fine venting book

http://www.heatinghelp.com/products/Steam-Heating-Books/25/146/Balancing-Steam-Systems-Using-a-Vent-Capacity-Chart-by-Gerry-Gill-and-Steve-Pajek

it works out, as a general comparison between vents, to approximately:

3 + ea Gorton #1 equals 1ea. Gorton #2

2 ea Hoffman #75 equals 1 ea. Gorton #2

2 ea Hoffman #4A equals 1ea. Gorton #1

ChrisJ

main vents failing

You mentioned having vents fail when they were relatively new.

Do you have them installed approx 6" above the main and around 15 inches back from where the main drops down to the return?

If they are screwed right into the main you are going to have problems.

steampunk_2

main venting

yes,they were all properly installed and not damaged by water hamer.  it really irked me because those 75's , they don't give 'em away.

crash2009

I just have 2 points to add for your consideration

 

1 since you have written off the Hoffman's anyway, there are a couple somewhat drastic procedures, that some have had success with.  Instead of boiling in vinegar, soak them in CLR for awhile, then give them a whack with the handle of a screwdriver.  This sometimes will free the stuck mechanism.  More than one whack is sometimes necessary



2 have you looked into the reason why a new vent stuck.  Did the vent stick open or closed.  What is your normal operating pressure?  What pressure does your pressure limit device shut the boiler off? 

Have a look at these video's to see how several types of main vents are constructed. Video's courtesy of Gerry Gill's website.  http://www.gwgillplumbingandheating.com/webapp/GetPage?pid=610

nicholas bonham-carter

testing vents

i second the question of pressure at which these vents are operating. they can become paperweights when subjected to pressures over a few pounds.

for that reason, and because you can see whether you have enough venting, get a good low-pressure gauge [gaugestore.com 0-3 psi].

as the boiler starts to make steam, you can see the back-pressure of the main vents. inadequate venting will cause the pressure to rise above the desired 2 ounces, possibly causing short-cycling even before the air has escaped. when the vents have closed, then of course the pressure will rise to the cutout set on the pressure control. if your boiler is perfectly sized to the radiation, then the pressure will not rise, as the steam will be condensed as quickly as it is produced.--nbc

steampunk_2

main venting

thanks again for all the feedback.



no, they didn't get blown up by pressure.  they all worked for a while and then they would intermittently stick open.  like i said i boiled them in vinegar, they'd work for a while, then sometimes stick open and not close on steam,  and this happened on two different systems.  the gortons are bullet proof.  i still have one of the 75's because i can't bear to toss after what it cost.  tell me what "CLR" is and i'll try boiling it in that and whacking it a couple of times.  i was so ticked off about that one #75 that i wanted to send it back to hoffman to test but it proved to be too much of a hassle.  and to the author of the venting book, thanks.



and thanks to everyone who knows his steam stuff, who reads these threads and takes the time write to help the rest of us hackers out.  its a beautiful thing.

Rod

CLR

Hi - "CLR" is a the trade name of a common cleaner that is used to remove lime deposits from house water fixtures like faucets, shower heads etc.   Most supermarkets and/or drugstores (CVS and Rite Aid) carry it in their household cleaning product sections. The "CLR" stands for Calcuim, Lime and Rust. It's a bit more acidic than vinegar.

- Rod