Main Vent selection

laldog30cs

Thanks in advance for some really great insight.

My question is this:

If in fact there can never be too much venting of the main, what is the best option for replacing the Dole 1933 Air valve that is presently being used?

I'm looking at Gorton #1 and Hoffman #75 as my main options. There's quite a price different between the 2, and my instincts tell me to go with the more expensive Hoffman. Is there compelling reasons why I should choose 1 over the other?

BobC

The Hoffman will vent longer (it closes at a higher temperature) which is a good thing but it also vents at half the rate which can be a bad thing - how long is your steam main?

In any case either will be a great improvement over old Dole vent.

Bob

EzzyT

Like BobC said what's the length and size of your steam main? That all factors in on what size and how many steam main vents you'd need

JUGHNE

He was comparing a G-1 to the 75. Isn't the 75 faster/larger than the G-1. But we consider the G-2 twice as fast as a Hoffman 75?
(For about the same money).

EzzyT

JUGHNE yes you are correct

Steamhead

The Gorton #2 is 3-4 times as fast as a Gorton #1 or Hoffman #75. Sure it costs more, but it's less expensive than multiple smaller vents.

But to make a proper recommendation, we need to know the length and diameter of the steam main. If there are other steam mains, include them too so we can get the whole picture.

BobC

My bad, I thought he was comparing the G2 with the Hoffman. I've seen the Hoffman go for about twice the price of the Gorton #1, since it is the same as 1-1/2 G1's it can be a good choice if you want the higher vent closing temperature.

Bob

gerry gill

im a big fan of the Gorton #2 vent personally.

EzzyT

Gerry your the vents and trap testing King

MattRuocco2

Is it a big deal if I don't install a Gorton #2 on a 6" extension? The #2 is huge, over 6.5" tall and i can only fit it as-is between 2 joists on the ceiling. I could maybe do a 3" extension, but that's it. Thoughts before i order?

Fred

A 3" extension will be fine. many use no extensions.

JUGHNE

Many use a 90 ell, then a piece of horizontal pipe that might get you to a place of more head room, then of course 90 ell up.
I believe that the off set in piping like this might keep a "shot" of water hammer from killing the vent. (There was a reason that the WW1 trenches zigzagged back and forth, keep them from turning into a "shotgun" row house. )

I also add a wye strainer in the horizontal pipe with a blow down ball valve. A bit more obstruction for dirt and water bullets, and cheap insurance for about only 15% cost of one G2 vent, and one strainer could protect more vents at that point, so the insurance payments drop like a group or fleet rate.

Dave in QCA

I like to use a Gorton 2 if the mains are not insulated, Hoffman 75 if they are insulated.

Abracadabra

Dave in QCA said:

I like to use a Gorton 2 if the mains are not insulated, Hoffman 75 if they are insulated.

@Dave in QCA just curious, why the different vent for uninsulated vs. insulated. I know the 75 will open up sooner vs. the Gorton staying closed longer. I just can't think of why to use one over the other if pipes are uninsulated vs. insulated.

Dave in QCA

What I have found is that when running one cycle per hour, even at 55 minutes off time, insulated pipes may not cool sufficiently to allow the G2 to open. In fact, I just checked some mains at my place today. A long distance from the boiler, in a cool room (65F), 55 minutes after the boiler shut off, the temp of the 2" main under the insulation was 132F, measured with a simple pocket probe analog thermometer. At this temperature, the air in the main will close the G2, even if the G2 itself does cool off more and open up. On the other hand, if the mains were not insulated, they would have cooled much more and the G2 would do a great job of venting the mains. For the insulated mains, the Hoffman may not vent as fast as a cold G2, but it sure vents faster than a warm one.