One pipe system has gone out of whack

panick007

About a year ago, with help, advice and encouragement from many on this forum, I installed a new Peerless boiler. (Pre insulation pics here on page 2

https://forum.heatinghelp.com/discussion/189734/new-drop-header-disappearing-water

I have 2 mains, one short that services 6 radiators on 3 floors and the other long in comparison that services 8 radiators across 3 floors. Originally there were no vents on the mains but I added them when I installed the boiler. The short main has a single Gorton #1 air eliminator and the long main, which takes quite a bit longer to fill with steam, has an antler with four #1’s. I also added air eliminators before the last radiator on each main. The system ran great, quiet even heat throughout the season, no complaints from anyone that it was too hot or too cold, pressure was pleasingly low.

At the start of this week ago I started noticing something was off. The thermostat indicated the house was at the set temp yet certain areas of the house felt cold. Today I’ve finally had a chance to look at it. First I noticed the pressure was high, I have 3 gauges, the useless 30#, a magnehelic -5 - 0 - 5 (usually my pressure is between 4 and 5 on this gauge) and a winters p301 (0 - 32 inches water). The pressure was building to the top end of the winters gauge and occasionally burying the needle. When a felt the main, the short main was only very warm, not hot and the radiator runouts were cold. I closed the king valve to the long main and then the short main filled with steam and the radiators all filled, but when I went back to the basement I saw that return water had been pushed backwards into the long main and spurted out the main vents. Not a lot of water, looks like a single pulse probably. I’ve been trying like heck to “think like steam” and understand what is going on here but not coming up with anything. Water level is correct, using 8way so water is purple. Where should I start with the troubleshooting?

Jamie Hall

First off, not a bit surprised that closing a king valve to a main resulted in water being pushed out of the boiler into that main and out of the vents. Exactly what I would expect to happen.

However, you don't mention whether there are king valves on both mains — and if both of them are completely open at all times. King valves must be either one or the other — not halfway — and if they are closed there must either be a closed valve on the corresponding wet and dry returns (if any) and there must be a provision for condensate return on both sides of the valve.

If the short main is "only warm" it isn't getting steam, or at least not much steam. So… you need to find out what's blocking the steam.

dabrakeman

If nothing has changed since last year I might first double check the functionality of the main vent on the short main and the eliminator at the top on that side. Either that or the king valve on the short main if you have one.

panick007

@Jamie Hall Yes, there is a king valve on each of the 2 mains. They are both always open all the way, I do close them and reopen them occasionally so they don’t seize up. I did put a valve on the return side, but it’s after the 2 separate returns come together before the Hartford loop so I can’t shut them off independently.

@dabrakeman I can definitely hear the short main vent huffing so it definitely is working. I’ll check the eliminator at the top on the short main side.

Before I installed this boiler there were no main vents/air eliminators anywhere on the system, just the vents on the rads (and no obvious place where they might once have been, I had to add fittings to the mains in order to install them).

Jamie Hall

If the vent is "huffing" there may be condensate pooling somewhere in that short main — perhaps right at the valve. What kind of valve is it? Plug? Ball?, Gate? Please don't say globe… and is it full port?

panick007

@Jamie Hall They are 2” full port gate valves, installed on each main as it rises out of the drop header. The mains rise up and are physically touching the basement ceiling then slope down around the basement until they drop into dry returns, which slope down to near the boiler then drop into a combined wet return.

panick007

i will add there is no sagging or low spots on the mains, there is one section of the long main, after the last radiator runout, that has a less pronounced slope but it is definitely sloped down toward the boiler when I put the level on it.

delcrossv

Is the cold main the one withthe king valve mounted on the 45 angle?

mattmia2

Is the boiler water line stable? is there additive in the boiler water? it may be priming and throwing water in to the mains. it could have had more oil work its way back to the boiler and be surging. Are the vents on risers on the main that isn't heating or could water in the main get to the vent?

Jamie Hall

https://forum.heatinghelp.com/discussion/comment/1825480#Comment_1825480

Oops. You have "returns" directly connected to the steam mains at the far ends of the mains which come back around and join before they drop to a wet return? That is a no-no. Follow the steam around the mains and these "returns" and see if you have a problem with steam in one of them getting far enough to block air removal in the other.

RTW

panick007 sounds very knowledgeable along with these pros who commented

My advice:

The quote "When you have eliminated all which is impossible, then whatever remains, however improbable, must be the truth" 

Regards,

RTW

panick007

@delcrossv Yes, the cold main is the vertical riser and the hot one is at a 45° angle. Historically, that short main was the quickest to fill with steam.

@mattmia2 The boiler water line is not really stable. I should have mentioned this symptom. As pressure builds the water line moves lower in the sight glass and will go below the sight glass when the pressure gets high enough. It doesn’t seem to be bouncing however. There is 8-way in the water. It is possible that oil has worked its way into the boiler, I installed a drop header so in theory water shouldn’t be getting into the main. Not much room to raise the vent so I added a long nipple running in reverse to out the vent on. Here’s a pic.

@Jamie Hall I think I did a poor job of describing the returns. They join below the water line.

panick007

@RTW As my father liked to say, I have just enough knowledge to be dangerous.

ethicalpaul

I wouldn’t close a king valve during normal operation. Open it then see if your water level stabilizes. If it still drops then suspect water quality

panick007

@ethicalpaul I only closed the king valve long enough to see if that would send more steam into the main that isn’t filling. Those valves are always open 100% while the boiler is operating. By the way I just happen to be watching your “Squick” video and it has me thinking that maybe my definition of a bouncing water line is wrong. In your video there is a lot of water being carried up into your risers but your water line is barely moving in the sight glass. It’s probably safe to say I need to skim the boiler today, but I wonder how that could be effecting just the one main and not both. It seems like there must be more than dirty boiler water?

neilc

https://forum.heatinghelp.com/discussion/comment/1825554#Comment_1825554

in your reply to @Mattmia2 you mention as "pressure builds",

to what pressure are you building?

have you serviced the pigtail ?

ethicalpaul

https://forum.heatinghelp.com/discussion/comment/1825569#Comment_1825569

trust me. Surging can drain your boiler. Pressure is not the issue most likely in a 1-pipe system.

Skim your boiler, that’s all I’d be doing

Watch this short video see if it looks familiar

https://youtu.be/WSRvvNQ5WLc?si=Stjkw_HHoD7jixNL

panick007

@neilc I have one gauge that reads from zero to 32” h2O and after the main vents close the needle on that gauge will max out. I’ll check out the pigtail.

@ethicalpaul Thanks for the video. I guess I know what I’m doing today.

pedmec

Flush the 8-way. Then refill the boiler and add fresh 8-way if you want to leave it in. Water chemistry is extremely important and the 8 way cleaned the boiler very well you are going to have very **** water composition. its very easy to do and don't cost anything but time. you might be surprised.

panick007

@pedmec That’s exactly what I decided to do. I flushed the returns and they were very dirty. That got me to thinking about how the new boiler might have helped dislodge some rust & scale and that would all wind up back in the boiler. I drained some water off the bottom and it was really dark so I drained it all. Waiting for it to cool a bit more and then I’ll flush it and refill.

panick007

i flushed the boiler until the water ran clear(ish) then refilled. Added about 1/3 qt. Of 8-way and fired it up. Pressure is remaining steady at just under 1 inch h2O even after the main vents close and it’s been running about 20 minutes. Water is pulsing in the sight glass so next weekend I’ll skim it.

ethicalpaul

it’s good to skim first since after the skim you have to drain extra water anyway

109A_5

When you are all done skimming and flushing, getting the junk out, I would only add just enough 8-way to get the PH where you want it.

As far as the higher than normal (for you) pressure, with water or foam being thrown up into the main(s) restricting the flow of the main(s) that very quickly makes the boiler oversized, since you have blocked off the path to the load, so the pressure will rise rapidly.

panick007

@ethicalpaul I agree, skimming first would have been ideal, but I really started thinking that the issue was more than just oil on the surface of the water, the water was just so brown. I have a busy week ahead and hopefully I won’t be getting complaints from the ladies of the house about the temperature. Next weekend I’ll skim it for a few hours.

panick007

@109A_5 That’s good info. I have to admit that, although I’m pleased that the system seems to be functioning well now, I really have/had no idea what the problem is/was. I ordered some PH test strips, next weekend I’ll try to get the ph right.

panick007

Does it make sense to add a temperature gauge of some sort for skimming, to help maintain the temperature below the boiling point? Has anyone done that?

ethicalpaul

https://forum.heatinghelp.com/discussion/comment/1825696#Comment_1825696

no. I have a temp gauge on mine but I never look at it. Just skim it when it’s still warm from an earlier call for heat. You don’t have to do it for hours.

ChrisJ

https://forum.heatinghelp.com/discussion/comment/1825444#Comment_1825444

Why would that happen if the equalizer did it's job?

Jamie Hall

With the king valve closed, there is no pressure in the main beyond it. There is still pressure in any wet returns, since they are not disconnected from the boiler.

Now if there are no drips or other return connections beyond the king valve, no the water would not be pushed out. Even one connection for condensate return beyond the king valve and splurk.

ethicalpaul

https://forum.heatinghelp.com/discussion/comment/1825694#Comment_1825694

It was dirty water surging, seems like to me

panick007

indeed it was dirty!

mattmia2

It is more likely that the water will get dirty than it will suddenly find some more oil after a year unless it was in the feed and was added slowly or something. Maybe oil that was in mostly cold parts of the returns could move very slowly. The hotter you keep it while skimming the more easily the oil will flow out. If you heat it to get it to near boiling after you raise the level that should help it happen faster. It will still be hot with you add a few gallons of water but not as hot as it could be. You didn't add more additive in the spring or fall did you? It is easy to go too far and make it prime.

panick007

I did add some new pipe and fittings when I installed the main vents and the riser vents, but that was the beginning of last heating season. I suppose it’s possible some oil worked its way down but there were no issues last season and this season the issues only developed about 1 week ago. Yes I did add 8-way in the fall when I started the boiler. Maybe that loosened up some scale and made the water dirty. It really only got below freezing here in the last 2 weeks so I may not have noticed so much the cold radiators.

ethicalpaul

Maybe that loosened up some scale and made the water dirty.

Yes that can happen. But once you get the water clean and get a little maintenance dose of 8-way you will be in good shape.

mattmia2

was there already additive in the water and you added more? some is ok and perhaps slows corrosion. more isn't better, if you get too much it will prime (foam) and throw water in to the mains. at what concentration it starts priming has a lot to do with the chemistry of your fill water.

panick007

I was not adding to water that already had 8-way, however it’s entirely possible I added too much because I didn’t measure at the time, just poured from the container and guesstimated. Now it’s actually a measured amount.