One Pipe Parallel Flow w/ 2 Mains-No Steam From One Open Ended Main

lincolntaggart

Its a new install. Existing vents were in disrepair with no air being eliminated. I changed the venting in order to maximize using sizing chart.

Skimmed on day of install. And again after 2 weeks. Surging in sight glass. Cycling on lwco.

Ultimately, my issue is ( defeating as it is ) ...ugh:

I have no steam from the 26ft x 2 " open-ended main. It shows 160...180...190 degrees but no steam.

The other main is 62ft x 2 1/2" it gets steam like crazy.

They each had one Hoffman. I installed 4 #75 on a branch on 62ft. I installed 2 #75 on 26ft. It appeared that longer main was venting too rapidly. So, I began moving one Hoffman over to other main in an attempt to balance the mains.

I started at 4 on one and 2 on the other. Then 3 and 3. and Finally 2 and 4.

After, I installed full port ball valves and left open ended. The long main vented in under 2 minutes. While the shorter was open for 20 minutes with no steam. FLIR shows 180+/- degrees on short main. Long has 210.

On short, I can hear water draining. Is the 180 degrees from wet steam. How can it be condensate? There are only 3 runouts on short run and those 3 rads are ice cold.

There is a poor insulation job on long run. There is no insulation on short run. I did not install near boiler insulation.

How can there be no steam from short main?
Where is the water coming from? ( Short wet return is 180, too)
Is my near boiler wrong and creating wet steam?

BobC

You have to make sure condensing steam can drain back to the boiler. Try monitoring the steams progress down the bad main to see if there is a point it seems to stop.

Have you gone over every inch of the non working main to be sure nothing is pitched wrong? Is there any chance someone stuffed a rag into an open pipe and forgot to retrieve it?

Bob

KC_Jones

At 180° that is for sure condensate temperatures. Have you checked the slope of all the pipe on that run to make sure it is all sloping away from the boiler and that it's straight? You say you hear water so it sounds like you have water laying somewhere that is cooling the steam and stopping it in it's tracks. Are any of the rads on that run heating at all? I would also suggest (once you figure out the issue) you are still light on venting. If you stick with the Hoffman's you will probably need 2-3 on the 2" line and probably 8-10 on that long 2 1/2" line.

lincolntaggart

The whole bad main is getting to 180. So its not clogged, and I get some air coming out but not like other main. and no steam. its like all the steam is favoring the larger pipe.

I can see on thermal it starts going up risers but only 1 foot

Jamie Hall

Something is blocking that short main. Step one is to use your FLIR and go along the full length of it; I'll bet that somewhere along there you will find the temperature drops rather abruptly.

It might be a dip in the pipe. It might be something in the pipe (???!! it's happened!). You say you have full port ball valves -- where along the pipe? Because a partly open valve will do that quite happily. Or unhappily, depending on your point of view (don't ask me how I know...). Never mind a reduced port one.

lincolntaggart

@kc-jones I didn't get a level on it. it appears to have slope. ill have to check for sure. it looks like it slopes away though. 0 rads getting hot on that main.

BobC

If it looks good with a level then stretch a string along the n=main and look for any dips in the pipe.

Try to find out where the steam seems to slow down and examine that area very carefully.

Bob

lincolntaggart

@Jamie Hall I removed my vents at the end of each main and temporarily installed ball valves so I could see how long it takes for steam to arrive. ( then I can shut the valve ) The long main gets steam in a few minutes. the short run could probably be open now ( I left there 2 hours ago ) and it still wouldn't have steam.

I had it wide open for 20 minutes and no steam. Some air, sound of water, but that's it

lincolntaggart

and... before I updated the venting. There was a Hoffman 79 on one and and antique Hoffman on other. and neither vented at all.

How is it now...that I made it better....it doesn't work

Danny Scully

For god sakes man strap that expansion tank up, then worry about the heat!

KC_Jones

What kind and size vents do you have on the radiators? You are obviously getting condensate in the 2" main by the temperature. I wonder if it's possible you have so much venting on the rads (too much to make up for the previous lack of main venting) that it is indeed robbing most of the steam. The tiny amount of steam that is getting in is condensing and running to the end? How long does it take for this main to get to 180°? Does it take a long time to get to that temperature? Gerry Gill has a story in his balancing steam book about 2 rads on one pipe and one wouldn't heat. He removed one rad and still couldn't get steam out of the pipe. Anything is possible. I would still do all the checks that have been suggested already. Always start with a long check list and eliminate one thing at a time.

lincolntaggart

@ Danny Scully Already replaced with st-5 and associated piping.lol. can you believe it did not fall like that? that's how it was installed

lincolntaggart

@KC_Jones Ill take a look but... rad vents are dated and in need of updating too. I know the g gill anecdote. wouldn't the rads need to get warm in essence so steam can condense.

it barely goes up the runouts.

I should just cap the vents like it was when I got there. lol.

When I have both mains open ended. wouldn't you think steam would travel path of least resistance?

Isnt 26 feet easier than 62 even though its 2 inch vs. 2 1/2?

Maybe there is bad slope?

KC_Jones

I would lean towards slope, but I am not there looking at it. I had one that "looked" perfect, but when you put a level on it, it was obviously pitched the wrong way. Kind of a head scratcher until I put the level on the joists my eyes were using as reference...then it made sense. Check the pitch AND use a string line to check that they aren't sagging. Also remember if you remove a sag you potentially change a pitch. One side of a sage slopes opposite the other side. Steam is full of subtleties.

JUGHNE

It starts up the risers about a foot? Have you removed the rad vents to see what happens with the risers. I know it doesn't make sense but might tell you something.
Maybe a water pocket above the boiler around the area of those 3 90 ells, all those horizontal pipes should drain away from the boiler, actually the entire main.... but it seems it should hammer though?

This may not fix your steam distribution problem, but if you still have surging this may help with that. I set up a skimming port on that "Dunkirk" side tapping design and as you look in across the top of the sections you can see that the push nipples are only about 1 1/2" inside. If that is your case when you skim out of the 2 1/2" side tee then all the water is coming from the closest section. I added a 2 1/2 X 1 1/4" coupling on a short nipple where your plug is. This raises the skimming water up above all the sections and your water moves up thru the entire boiler.
Maybe yours is not so but worth looking at.

But is a good looking install compared to the old boiler picture.

Fred

That short run, I assume is the one with the 2 Hoffman 75's on it. The antler that those Hoffmans are mounted on looks like it might be slightly piched back towards the vents. If so, that might be holding enough water to block the vents. try tilting that antler up a little more so that it pitches back towards the main.
On the Main with the 4 hoffmans are, I'm trying to figure out what the pipes are coming from opposite directions. I think the insulated one is your long main but where does the un-insulated one come from? Are your new vents at the same location as your old ones were?

lincolntaggart

@JUGHNE Dunkirk 2 x 1 1/4 to bring water higher than sections. Yup. I'll try that. Cause looks just like your saying the plugged tee. Thx!

And I may as well take a rad vent off....just to see

Danny Scully

Simplify the problem, and look at the usual suspects: air, dirt, piping. According to Bryant's installation manual, there should be 15" of horizontal header piping before the system take-offs, which there isn't in your installation. I'm not saying that's causing the problem definitively, but it's something to consider. Also, you said you skimmed it twice - what skimming method are you utilizing? You may have to repeat this process a few times. Finally, what is the pressuretrol set at? I think yours should be set at .5 and 1.5. Keep us posted, and good luck!

lincolntaggart

@Danny Scully in re-reading manual...I knew about the 15 inches. I omitted adding that here as a suspect. I hope thats not the issue...

Set at .5 and 1 diff.

I'm going back tomorrow. I'll keep yall updated

lincolntaggart

Skimmed thru tapping into bucket. Cycling to keep water hot just before boiling. 3 hours on install day. 3 hours 2 weeks later.

Steamhead

If at all possible, pipe that boiler with two risers to the header. This is actually a Dunkirk, which will never make dry steam unless you go above and beyond the minimum specs in the manual.

Abracadabra

Troubleshoot by shutting all radiators attached to long main and cap the vent on the long main. See what you get out of the short main now.

Is boiler properly sized? I'm thinking undersized. Once steam hits radiators on the long main, vacuum caused by condensation there sucks any steam that might have an opportunity to get into the short main and steam is condensing in the main due to lack of insulation before it hits radiators on the short main

lincolntaggart

New information from today:

If I remove plug from where vent on short run "used to" be. At the tee, at the end of main....

And look into pipe, straight down riser...water fills up and overflows and begins to fill main.

Eureka!

It is coming together now.

This is why I have 210 degrees only in first 6 feet of main and 180 degrees in remainder....

But why?

A dimension is good. Much more than 28 inches and same as other main.

I know wet return is not clogged because I can drain it. It's completely empty looking down plugged tee at end of run.

Is it scaled up badly but not completely clogged?

Is this my problem?

2 of three rads on this line were improperly sloped. I resolved this today.

Fred

Your Hartford loop looks like it is just about at the bottom of your boiler block, certainly at the bottom of your sight glass. Being that low, it would seem that it defeats the purpose of the Hartford loop. I'm wondering if, being that low, it is allowing most of the water in the boiler to push back through the wet returns. Try closing the valve you have on that Hartford loop and firing the boiler and see if the short main gets hot. If it does, you need to move that Hartford loop up to a couple inches below the normal water line.

BobC

Why isn't that water draining from the main? If it's overflowing something ain't sloped right.

Bob

Jamie Hall

EEK. Bob's right. Something is sloped all wrong -- or... what does that riser drain into? Whatever it is, it isn't draining much (it must be draining a little). Trace that line all the way back to the boiler and see if you can figure out what's happening.

Also... I presume there is an equalizer on the boiler? From the header to the top of the Hartford Loop (never mind the elevation of the loop -- at the moment that doesn't matter)? And that it is open and free?

nicholas bonham-carter

My guess is over-pressure forcing up the water level in the wet return, (1.75 inches per ounce of pressure), and blocking the path to the vent.
Put a temporary ball valve where the main vent was, then fire the boiler long enough to make some pressure. Cut off the boiler, and periodically open the valve. If the water rapidly stops overflowing, then it is a pressure issue.
You could also get a 10 ft length of clear plastic tubing, and use appropriate fittings to attach it to the boiler drain. Drape over some pipe on the ceiling, and as the boiler fires, the water in the tube will elevate. That height may be above the vent.--NBC

lincolntaggart

Dirty water is rising from wet return...it's not coming from header.

Maybe I got it figured...[ Ganesh ;-) ] Bryant manual calls for 6 inches on Hartford tee.

Can't wait to try tomorrow.

You would think my boss would be happy if I get it working... but...

lincolntaggart

Also, it always goes out on low water. It's never yet gone off on pressure.

BobC

With an open 2" main the pressure must be pretty low, have you tried putting a low pressure on the boiler to see what is going on?

Bob

lincolntaggart

@Hatterasguy I have mine at 6 inches. Like @fred. Water is pushing thru Hartford loop because it's too low. Too much water going into return and flooding main. Then goes off on low water.

It appears sensible on paper because it resolves all symptoms. Low water, dirty return water rising up wet return, no steam

Gotta try. Chalk it up. Update tomorrow

Abracadabra

Has the boiler been properly skimmed. How steady is the waterline while steaming?

lincolntaggart

Skimmed 2x. 3 hrs on install. 3 hours 2 weeks later.

Upon cold start, water level drops completely in first minute after steaming and goes off on low water. Then it goes off on low water intermittently after that. Never on pressure.

BobC

Might be time to use a wand to wash that boiler out good

Bob

Fred

Most people, trying to solve a problem won't ignore any possibility, especially on the advice of those who chose to critic almost everyone elses comments but offer no potential solution that might be even a remote fix. Something is causing water to back up out of his wet return and into the main. It seems logical to look at where that might be (somewhere between the boiler and the top of that drop from the main, even if it is not typical.

Jamie Hall

lincolntaggart said:

Skimmed 2x. 3 hrs on install. 3 hours 2 weeks later.



Upon cold start, water level drops completely in first minute after steaming and goes off on low water. Then it goes off on low water intermittently after that. Never on pressure.

Eh? As others have said, ignore the Hartford Loop issue. It's not relevant here. But your comment above may be. The water level shouldn't drop like that. In fact, it shouldn't drop more than an inch or so.

Let's take a deep breath here, and go back and look at the system. The whole system. All the pipes. The loss of that much water, that fast, suggests strongly to me that somewhere in there there may be a pipe which is just barely above the normal water line -- which should have been a wet return, but isn't. Even a small increase in pressure could back water into that line. Another thing to look at is the equalizer, which I mentioned above. If that isn't doing its job, then a small increase in boiler pressure will back water right out into the returns and from them into the risers.

But I urge you -- examine the whole system.

Fred

I tried to inch through his pictures, above. His header, riser to the header/mains,equalizer all look good. Wet returns are at or very near the floor. The only thing that looked dubious to me was how low the Hartford loop is to the bottom of the boiler. Not something that we would typically suspect but with a single side tap riser to the header, it's all I can find to question. I guess we'll know tomorrow???

lincolntaggart

Btw. This was original. I can't wait for my install to work...comparitively

hvacfreak2

Man , crank that pressuretrol to the max and shoot that obstruction out like a freaking cannon ball man , BLAM !!! nasty old black oil soaked rag and a gallon of tar right out of the pipe !!!

Little comedy relief , carry on , please.

lincolntaggart

I mean. There is too much wrong with this. right..but it worked

KC_Jones

Did I read correctly that you take off the vent at the end of the main and suddenly water is coming up from the return? Is that correct? That indicates pressure on the return side, but no pressure on the supply side.