Balancing One Pipe Steam

Rusty2

3 main loops:
Loop 1: (49' x 2" pipe) + (7' x 1.5" pipe) + (22' x 1") pipe, 2 Gorton #2's at end of return
Loop 2: (44' x 2" pipe) + (38' x 1.5" pipe), 2 Gorton #2's at end of return
Loop 3: (50' x 1.5") pipe + (22" x 1") pipe, 1 Gorton #2 at end of return
Pressuretrol set at 0.5 psi to 1.5 psi cut out verified by 0 to 3 PSI gauge on a tee off the pigtail shared with Pressuretrol.
I keep wondering about 2 large Honeywell gate valves ("King Valves") coming off the header with no turn handles on their valve stems. One valve feeds Loop #3 (the smallest loop). Both Loop #1 and Loop #2 (the larger loops) share the other valve. "Obviously" they are both all the way open...right?
Testing the system on a fall day, not too cold, Loop #3 gets hot right away and the Gorton #2 closes.
Loops 1 & 2 take much longer to heat with the boiler cycling frequently. It seems that even with hot main returns and the radiators heating that all 4 of the Gortons never got hot enough to close on Loops 1 & 2. My belief (of them not closing) is based on taping them and they continue to "ring" while the one by itself on Loop #1 does not "ring" (when the system is hot) and reads at a higher reflected temperature than the other 4 valves.
With the system cold I turn the valve stems on the "King Valves" (counter clockwise) and nothing seems to happen. But then I notice one valve stem is slightly longer (with lots and lots of turns) I measure it with a ruler until it is the same length (approx. 1 3/4") as the valve stem for Loop #3. No matter how much I turn them neither valve stem gets any longer, but they continue to turn. They must be fully open, right?
I fire up the boiler. It seems to run for a long time, longer than before I opened up the one King Valve to be the same as the other, fully open. The PSI gauge begins to vibrate barely off of the zero mark (as usual), at just a fraction of an ounce...but then it just stays there vibrating right next to zero. The Loop #3 mains are heating up. PSI gauge still bouncing off zero at a fraction of an ounce (barely noticeable). #3 Loop is now heated and the Gorton #2 is closed. Loop #2 heated, but Gortons not closed. Loop #3 barely warm at the end. The Pressuretrol never cycles. The PSI gauge never reads any higher.
I shut off the boiler believing something must be wrong with the PSI gauge and Pressuretrol. They were both fine a few hours earlier when I tested without opening the other "King Valve". I go upstairs and the radiators connected to Loop #1 feel and smell like they are close to on fire. The big radiator on Loop #1 that is usually hottest first is heated only about 2/3 through.
I take the PSI gauge off and test it. It works. Did not take the Pressuretrol off to check the pigtail (yet), but I just took apart and cleaned the LWCO and the pigtail a week ago, so it's doubtful it would be clogged. Did opening one King Valve more cause a near zero PSI reading? I had the thermostat set high, so this wouldn't be a factor for the test.
Am I approaching Steam Nirvana, heating the system with an almost immeasurable fraction of an ounce of pressure?
There must be something obvious that I'm missing. Does anybody have any thoughts on what might be going on? Thanks

Jamie Hall

All of which is why I dislike -- with considerable intensity -- anything except full port ball valves on steam mains. There are two flavours of gate valves -- rising stem and non-rising stem. As the names imply, in one the stem moves and drags the gate along with it. In the other, the thread is in the gate, and the gate moves when the stem is turned.

Usually both flavours close with clockwise turning of the stem, though I have seen the reverse. So... try this: turn both valves clockwise as far as they will go. That should close both valves. Fire up the boiler; the pressure should rise -- probably quite quickly. If it does, wonderful. Turn off the boiler. If it doesn't, try the other direction. One way or the other, make sure you know which way to turn to close the valves.

Now that you know which way is closed (but there's more below...) turn both valve stems the opposite way and count the turns until they stop. They should both have the same number of turns, give or take a half turn or so. In theory now both valves should be full open. See what happens. If all is well, quit and go do something else...

Gate valves, however, have been known to fail. Sometimes they won't open fully. Sometimes they won't close fully. Sometimes the gate just sits there inside at some intermediate position and won't move at all.

If in the first test -- trying to shut both valves -- you found some evidence that steam was getting by one of the valves (main above warm or hot, pressure not rising as you would expect) that valve is faulty and not closing all the way. On the other hand, if the turns to fully open weren't equal, one valve is faulty and isn't opening all the way. In either case you have a problem. A steam valve on a main which isn't fully open doesn't just reduce the flow a little; because of the somewhat peculiar thermal properties of saturated steam it may reduce the flow of steam to almost zero -- even at, say, three quarters open.

In any event, if the little test of getting both valves fully closed, then equally and fully open, fails...

I don't like gate valves on steam mains. I like globe valves even worse. Full port ball valves are the way to go!

nicholas bonham-carter

I would think the gate valve handles would stop turning when either fully opened or closed.
One way to check would be to remove the bonnet, and see if the gates are moving as designed, as you turn the stem.--NBC

Rusty2

Thanks Hatterasguy - What confuses me is that before I opened one of the King Valves all the way the boiler would short cycle between 0.5 and 1.5psi before the steam mains were filled. Is that because with one of the valves not fully open more pressure was developed in the boiler since it couldn't escape as fast? Now the psi gauge doesn't move, the steam mains fill and the Pressuretrol doesn't cycle the boiler on and off. The boiler just runs full out until the thermostat goes off. Yes, balancing the system is a challenge. I'm considering adding a B & J Bigmouth vent on 2 of the mains to get the air out faster. Right now the smaller mains loop with only one Gorton #2 becomes charged with steam right away. The bigger ones with two #2's on each line take longer to fill with steam.

Rusty2

Thanks NBC - I am afraid the valves may leak if I take them apart to see if the gates are moving. Even though the valve stems have both reached a point where they don't get any longer they continue to turn counter clockwise.

Rusty2

Thanks Jamie Hall - Your test of closing the valves makes sense. I will try this tomorrow.

Jamie Hall

A pressure gauge not moving but the radiators heating is not a problem. In fact, it indicates that the venting is good and the boiler is reasonably sized! Be happy! Fiddling with the vents on the mains is the way to get balance; sounds like you are on the right track.

I gather that you now are reasonably sure that both gate valves really are fully open?

EBEBRATT-Ed

Maybe I am an idiot but those don't looks like gate valves they look like globe valves .

They also look like control valves which would account for stems that keep turning round and round.

Can you read any name or marking on those valves??

Looks like the valve stem pushes in and out

Fred

@EBEBRATT-Ed , looks like it says "Honeywell" on the side of the valve.

Rusty2

Ebebratt-Ed and Fred -
Yes they are both Honeywell. I just tried to close them as Jamie Hall suggested and realized that the stem on one of them just slides in and out without turning it. When I pull it out it's open and when I push it in it's closed.

EBEBRATT-Ed

Yeah, probably had Honeywell pneumatic actuators at some point. Or they could have been electric. Do you see any disconnected wiring or 1/4" pneumatic tubing?? any evidence of an air compressor??Those are control valves.

Rusty2

Hi Ebebratt-Ed - I now believe they are globe valves. No wiring, tubing or anything connected to them or in the area that I can see. Probably on there to blow down the mud leg.

Jamie Hall

My apologies to all and sundry, and thanks to @EBEBRATT-Ed -- I should have recognized that those things weren't gate valves.

EBEBRATT-Ed

@Jamie Hall no apology's necessary. I'm wrong more than I'm right especially the older I get! The "WALL" is proof the more eyes you get on something the better.