Rad Vent size advice?

John MacGregor

I have a one pipe steam system with only 1 main and a random assortment of rad vents that i'd like to replace. I rent the place and have figured out that the boiler is oversized, but my landlord will not replace it just because its too big so I thought that I could help out my system by getting bigger and better rad vents. I figure the faster all the rads heat up, the shorter my boiler cycles can become. At the very least, its a step in the right direction I hope.

I've read alot of good things on the board about Gorton and although I've checked out their web site, I'd still like to hear from the experts. Given that I am on the second floor, and the boiler that used to heat both floors now only heats mine (the 1st floor has forced air) can you recommend vents to try?

I also want to say thanks to Dan for writing such a great book. We Got Steam Heat proved to me that my landlord was slacking off on the boiler maintenance and I was able to make some easy fixes myself (insulating the pipes for starters!) that have helped me dramatically.

Al Letellier_4

rad vents

Use any good adjustable steam vent. A quality vent will last longer, so if you're going to be there a while, spend the extra money for some good quality vents. Vent Rite, Dole, Gorton and others make good ones. The adjustable feature will allow you to balance the heat a little better, especially if you don't have control of the thermostat.

John MacGregor

Problems venting too fast?

Just a thought...Is there such a thing as venting a radiator too fast? For example, if I put Gorton D's on all my radiators except the one in the room that the thermostat is located, would that cause problems?

Perhaps a water hammer resulting from steam rushing up the cold pipes? I know the system wouldn't be balanced but I wasn't sure if there would be any other problems as a result of venting radiators as quickly as possible.

DanHolohan

Yes,

that can be a problem, and for the reason that you named. Good thinking!

jesse the great

rad size vents

dan what if you tap a large air vent like a gordon D in the front and a smaller vent on at the end of the radiator would you still get w.h.

DanHolohan

The steam would arrive at the radiator

faster and leave the radiator slower. Interesting idea.

Steamhead

Jennifer, is there a vent

at the end of the steam main? If so, what make and model? And how long is the main, and what pipe size?

The answers will tell us what size main vent is needed, and whether you have the right one. With a big enough main vent, you won't need to use large vents on the radiators and risk banging.

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John MacGregor

Measurements to follow!

Thanks for the tip Steamhead - I'll measure tomorrow evening and post the results.

I hope it is as simple as replacing the main vent with a bigger one (and by simple I mean, something that I can do myself). The rads sound like they are going to pop their vents off when releasing air bursts!

Mark Eatherton1

Turn it down!!

Jen what pressure are you running. You shouldn't need more than 1-1/2 PSI.

ME

John MacGregor

Pressuretrol cuts out at 3 PSI

That is another problem that I'm asking my landlord to look at. Even though the dial is set to 1.5, and the cut in is at .5, the system's pressure gauge says that it builds itself up to 3PSI before shutting off. There is definately short cycleing happening but my landlord will not replace the oversized boiler just because of this.

What is worse, letting the pressuretrol kick in less often but allow more steam to build or fix the pressuretrol, possibly making the cut in and cut out happen more frequently? I'm trying to find workarounds for an oversized boiler that used to heat 2 floors of a house, and now only heats mine...

Fred Harwood

Short cycles

Since you're measuring radiators anyway, why not get the EDR of each, add them up, and compare the sum to the boiler's EDR rating? That way you would know just how oversized the boiler is, and if it could be downfired for better efficiency.

John MacGregor

Pig Tail cleaning?

I've been reading other posts about making sure that the pig tail is clear when concerned about short cycleing. About a month ago my landlord "cleaned" the pig tail because a blockage had caused the system to keep firing until the relief valve set off at 15PSI. Ever since then, the system has been short cycleing...I had attributed it to the fact that its gotten colder and the system has to work harder but I wonder if it is clogged again. Last night I found water in the pigtail - is that a cause for concern? I'd think that would indicate that as the steam cooled in the pigtail, some obstruction is in the way to prevent the water from running back down the pipe...

Fred Harwood

Short cycling

Perhaps now that the pig tail has been cleaned, your oversized boiler is short cycling due to fast pressure build. Check the radiation load to the boiler supply, and downsize the firing rate if possible.