Losing a ton of water in the boiler

Fred

Yes, Mains get vented fast. Radiators more slowly. If you want to make it easy on yourself, buy the Vent-Rite #1 or Hoffman #1A vents for your radiators. They are adjustable and will allow you to balance the radiators easily, even with the various lengths of the radiator run-outs or the radiator size, unless something is unusually different on one or two radiators (from your picture, that's not the case).

Jamie Hall

Yes. The whole idea of the exercise is to vent the mains -- and the dry returns, although a vent location on each main anywhere beyond the takeoffs to the radiators will do -- as rapidly as reasonably possible. Then all the radiator vents have to do is to allow air out of the radiator and steam in, and you can balance the system and get the heat output on each radiator just where you want it with the individual vents.

BobC

It depends.

If you have a setup where the main circles the basement and you have short feeds up to the rads and almost no horizontal pipes on the radiator feed pipes then you want vents like the Ventrite or Hoffman 1A's.

However if you have a short main that just circles the chimney and then have 10-14 ft horizontal runouts to the rads and risers to the second floor you need more aggressive venting on the rads and in some cases you might want to vent the risers as well as the rads. If your not sure what venting rate you need buy the Maid o mist 5L that comes with 5 different orifices so you can experiment without going broke.

In either case you want a lot of venting on the mains.

Bob

midiman143

Hey guys so I did some measuring and have a few more questions.

1. The vent pipe capacity article uses 3 minutes as a typical time, would you recommend doing that or should I unscrew the vent and time how long it takes to get there?
2. I measured the steam pipes and they "appear" to be uncommon sizes, these are outside diameter 2-1/8 copper coming from boiler, 2-3/8 black iron mains and 1-1/4 return lines. I assume I should use 2", 2.5" and 1.25" for my calcs.
3. So since I have two mains and they are basically the same size and each has a vent I did calcs for one "side" and will assume the other side is the same. So
2" pipe= 2.66'(0.023CF/LF)
2.5" pipe = 21.33'(0.03 CF/LF)
1.25" pipe = 15.83'(0.01 CF/LF)
Assuming 3 minutes to vent I got 0.859CF/ 3 mins = 0.286 CF/M which is over the capacity of the #35 vent right (0.11CFM-0.25CFM depending on Oz of pressure)

-Paige

Fred

The diameter of the pipes is inside demension, so the copper pipe would be 2 " , the black iron is 2 " and the returns are 1". How long are the mains? If they are 20 to 30 ft each, you can put a Gorton #2 on each of them and be fine. On a single pipe system, You really don't have to vent the dry returns, just measure the length of the main from the header to the current vent location or just past the last radiator run-out. Allow a little capacity for the air in the header but you don't have to try and get a perfect calculation. A little more capacity is fine. You can't really over vent a main, just reach a point where there is no real value in spending money adding more venting. The #35 vents too slow for a main unless the main is really, really short.
If you want to take the vents off, the thing you want to try and do is add enough venting to match however long it takes for steam to get to the open tapping so that, with vents, you match the approximate time of an open pipe. That's as good as you will get.

midiman143

@Fred Thank you as always for the reply, I appreciate your advice. I have attached 3 photos which essentially show the run I am talking about (1 out of 2 main lines). The 2" line is 21' and the 1" return is 16 feet roughly. You mentioned not venting the dry returns by if I understand my system correctly, the vent is at the end of my dry return correct, and therefor should be included in the rough calc.

I just did a quick calc using the 2" and 1" line capacities and came up with 0.7103 CF, and again assuming the 3 minutes time frame that gives me 0.2367 CF/m which is just shy of the 0.25 CF/m for the vent rite #35 @ 3oz. Have you found that mainline vents tend to lose alot of their capacity over time ? I am debating between the Gordon #1 vs #2. The #1 seems to be 1/3 the price of the #2 and the #1 would give me almost 3x the capacity as what my theoretical system requires. Should I just go with bigger is better and not worry about why the math doesnt exactly work out.

Fred

@midiman143 , to be perfectly honest, we have always estimated one Gorton #2 for every 20 ft of 2" Main. Again a "Rule of thumb". I think what might be throwing you off is the 3 Minute factor. We always say vent mains as fast as possible. Certainly three minutes is reasonable but, if you have a large enough tapping and vent and can vent in a minute or two, go for it! I wouldn't spend my money on a Gorton #1. Just not enough vent for a 20+ ft Main. Again, from my perspective if I were venting your mains, I'd spend the same amount of money for the Barnes and Jones Big Mouth vent as the Gorton #2 and get double the venting capacity. It's a no brainer. You can Buy the Big Mouth from Amazon or click on the store tab on this site then click on Vents on the right and it will take you to Amazon.

KC_Jones

I would suggest you reevaluate the way you are looking at the venting chart. Look at the lowest pressure listed and work from that. The reason being is that to get pressure you have to slow or stop the steam flow. Yes at 3oz the vent flows more, but you are slowing the steam down to do that. The boiler doesn't make pressure, system restrictions relative to steam production makes pressure.

I would for sure go with the #2. The #1 is 1/3 the price and roughly 1/3 the capacity.

EBEBRATT-Ed

I would vent the dry return. It's full of air on every shutdown and it's not going to go down into the boiler. When the water slides down the dry return the air displaced has to go somewhere. Pushing it backwards uphill to the end of main vent doesn't seem like the best approach

midiman143

UPDATE: Hello everyone again. I would like to thank everyone who has taking the time to respond, share their experience and help the education process this has become. The PSI guage has been installed and reads about 0.2-0.3 PSI when boiling and 0.4 at its max in operation. So it looks like throughout a cycle I am operating at 3oz-6oz which I think is good? The pig tail was taking off and was not clogged, but was cleaned to a further degree then it was before. All parts were reinstalled with tephlon tape and should be MUCH easier to ever take apart in the future. I know some suggested installing a union on the pigtail but I took the old one off with alot of force and dont see myself having to have that much difficulty the next time I clean due to the tape.

I also have some water data. So there is a 2" water head difference between max capacity and low water cut off. If we are on "away" mode, which the boiler is on only when we are home we are hitting the LWCO in 5 days or so. If we are home all the time, say a weekend, it looks like its about 3 days. Still no signs of any smoke what so ever, and I checked on this 8 degree day morning. I have plans to install the #2 Gordons this weekend.

Any other ideas/comments are welcomed!

Thanks again, Paige

Bob Gagnon plumbing and heating

Have you overfilled the boiler and looked hours later to see if there are any leaks? You shouldn't have to fill it that often...

midiman143

@Bob Gagnon plumbing and heating - Hi Bob, yes about a week and a half ago I filled the boiler up to the pressure release valve above the boiler. Its about 6" or higher above the top of boiler roughly.

MilanD

From the sound of your vent in the video, they are not closing. One of them will release about 8 oz of water per day, give or take. Multiply by number of your rads, and you are plausibly losing the amount of water you are losing. Clean or replace vents, and make sure they close on steam.

midiman143

@MilanD - I think you may be onto something. We have 7 radiators of which, 6 work very consistently well. We bought a new radiator vent last year that does hiss like the rest in the house so we are assuming most of the vents are working properly. We did clean them all in a vinegar bath last year as part of our maintenance. If we were running around the 0.4psi/6.5oz pressure, do you think that would be enough to hold some of these radiator vents open? I do plan to install larger main vents next week which i believe will help lower the pressure in the system.

There is one aspect I am still not understanding is if the main vents and radiator vents are supposed to close when they get warm, if my thermostat is still calling for heat, the boiler will still run and where does that excess steam/pressure go with everything "closed"? Right now its going everywhere, the main vents hiss and the radiators hiss at times. Where I am installing #2 Gordons I would think all the excess will just blow out these instead of the radiators due to the path of least resistance. I could be completely wrong with this one though.

Thanks again, Paige

KC_Jones

Steam should never come out of the vents, at least not a noticeable amount. Once steam hits them they close and that should be it.

Once they are all closed, if the thermostat is still calling the pressure will increase until either the thermostat stops calling or the pressurtrol **** it down.

You should be able to go month(s) without hitting the LWCO. I filled mine in October, haven't touched it yet. All systems are different, but I think everyone would agree your usage is excessive.

MilanD

What @KC_Jones said. Vents close when hit by steam. That's their purpose. If they don't close, they let the steam out, in essence, releasing water out of the system. Your question as to what happens if tstat was not satisfied when vents close is why everyone here advises against overnight setbacks in excess of 1-2 degrees. Steam systems can takes a while to swing temps up, which can cycle the boiler on and off multiple times, which is not as energy-efficient as a constant on cycle.

midiman143

Thank you for the advice @MilanD and @KC_Jones . I do not ever see steam from the radiator vents/main vent but like you say they are performing in a way that is not normal or in an environment they are not meant for, aka the higher pressure.

Would you guys say its normal to have a system shut off for pressure reasons to wait for the heat to catch up to the thermostat? Is there an easy indicator is the system has been shut off due to the pressurtrol?

KC_Jones

Steam is invisible, you won't see it. You could be dumping steam and not know it. Put a cold piece of metal in front of vent and if it comes back wet that means steam is coming out.

MilanD

You won't necessarily see the steam. Gurgling like the video is indicative of it not closing.

As to shutting off on pressure: if you sit next to the boiler you will see it turn off against the pressure when your new gauge shows it go above wherever you have it set on the ptrol. In general, appropriately sized and vented systems that are maintaining a temperature (so not coming out of a deep setback), should be able to operate without building more pressure than necessary to overcome pipe friction loss, about 1-2 oz per 100 ft of pipe.

So, I maintain my position that on a gas boiler, it is better to keep pressure low and sufficient to heat radiators across before pressure starts to rise, as in with system that's filled with steam to capacity, and then let it cycle on pressure. Gas valve is designed to cycle hundreds of thousands of times. Pressure usually drops quite quickly from, say 10 oz cut off to 0, that stand-by losses are minimal, and steaming is almost instantaneous after boiler fires back up. In my book it's more wasteful to burn gas to build unnecessary pressure, just to prevent gas valve from cycling. This is all for a system that's set up properly and optimally. And yes, this allows for heat to reach the tstat without making excess steam which, if boiler keeps making steam with ptrol set on a higher cutout, will stay in the system after tstat is switched the boiler off, and overshoot the set temp and overheat the space. And greater differential between outdoor and indoor temp, the greater heat loss. So, why heat the space above the comfortable 70 degrees F? It's wasteful.

For oversized boilers, functionality of operating on low ounces may not be achievable and building pressure may be the only way to heat all the rads.

From your posts, looks like your system is optimal, boiler is not oversized and you fixed main venting. Thus, get the rad vents to close, and you'll be set.

Fred

@midiman143 , What brand vents are you using on those radiators? Did you buy them from the Home Depot or Lowes? If so, they are likely cheap Chinese products and they simply don't work well.
You have small main vents on your system. You can't balance your radiators until you first get good main vents on the system
When your radiator vents continue to hiss, are the radiators hot all the way across? If they are not, then the vents will likely remain open and that is fine. It is usually only on the coldest days that a radiator will get completely hot all the way across and close the vent.
Do you have a 0-3 PSI low pressure gauge on your boiler? You really need to see what pressure your system is running and the old 0-30 PSI gauge just won't let you see what is happening down in the range a steam boiler should operate at. Install one.
Once you install that low pressure gauge, it is completely possible the Pressuretrol needs to be calibrated. Most of them do. We can provide you that procedure, when you are ready for it but it takes a low pressure gauge to properly set it.
As for where the steam/heat goes when all vents are closed, the steam condenses in the system, mostly in the radiators. That process is what creates the heat you feel. Once it condenses and goives up its energy(heat), there is now room for more steam to enter the radiator and repeat the condensation cycle. A properly sized boiler will produce about the same amount of steam as your connected radiators can condense so the would never build enough to cause the Pressuretrol to shut the boiler down. The Pressuretrol is then just a safety device to ensure the boiler pressure never gets out of control. The boiler would only shut down because the Thermostat is satisfied. Unfortunately most boilers are somewhat oversized, meaning they will produce more steam than the connected piping and radiators can condense. That's when you build pressure (more steam in the system than it can process). Then the Pressuretrol becomes a working part of the heating process and it shuts the boiler down when the pressure builds beyond the desired setting, typically about 1.5 PSI. When enough condensation occurs the pressure drops to the cut-in setting and the boiler re-fires.
Adding enough Main vents allows the steam to push all the air out of the mains without back pressure. That gives you a few minutes of extra operating time for steam to get to the radiators before pressure starts to build (on an over-sized boiler).

midiman143

Thanks for the great insight guys. Where the radiator vents are hissing I have to think there is a ton of steam being let out each cycle.

@KC_Jones - My boiler is oil, does that affect anything in your opinion? I wouldnt think so.

@Fred - We have 6 adjustable hoffman, and 1 adjustable Watts. I dont believe either brand is considered the cheap crap from HD/Lowes correct? The PSI guage has been installed and reads about 0.2-0.3 PSI when boiling and 0.4 PSI at its max in operation so far. I did see a 0.9 PSI reading just once yesterday but that was once. Thank you for also giving insight as to how the system pressure changes with the water phase shifts. I recall Dan saying steam has a volume of 1700x its liquid state so that does explain quite a bit. As for the radiators, they all tend to get hot all the way across for sure with each cycle by the time the call for heat is off.

Thanks again guys and will give updates as I install the main vents, and check the pressurtrol at some point in the future.

Fred

@midiman143 , the Hoffmans and Watts are good brands of radiator vents but something is wrong if they don't close, especially if none of them close. The Pressure seems good. Are you 100% sure they are not closing? You would see lots of condensation, almost like a spray coming out of them if they are open. I'm thinking what you hear may well be at the end of a heating cycle there may be enough of a vacuum in the system that it pulls the vents open and what you hear is actually air being sucked back into the system. Your new Main vents should help that.

MilanD

@Fred

Look at the earlier video of the vent. Definitely gurgles as if not closing when steam hits them. Why this is on all of them, it's puzzling indeed.

And to @midiman143 , looks like your oil boiler is sized well and is not building pressure. Leave ptrol set at .5 and inside wheel at 1. If you don't see pressure over 0.9 psi, you are pretty much optimal. Increase main venting if you haven't already, and figure out why rad vents are not closing. You can put a glass over the vent and see if it fogs up/steams up at the end of the cycle when the rad is hot all the way, on a cold day. That'll tell you if it's closing. Since you did the flood test and other returns are all dry and the water is still getting out, the only logical place left is the vent. If they all sound like the video you posted, I am 100% certain they are not closing when steam reaches them. Could be a bad batch of vents. Try tapping it when it gurgles like that one on the video, and see if you can stop the gurgle. I have a few older Hoffman #1 and they sometimes do this too.

Fred

@MilanD , I did just look at that video again and I have to say I don't believe steam has gotten to that vent yet. It is hissing as if the pressure is well above what the OP says his gauge indicates but, when a Hoffman 1A fails to close, the spray from condensation is like a mist fountain that sprays about a ft in the air and about a ft. diameter. You don't need to hold a mirror up to it, especially at the velocity that video implies. I'm baffled.

midiman143

Thank you @Fred and @MilanD for the replies. We bought one new radiator vent last year and even that did the gargle so we figured this is either normal, or normal for our current steam set up.

I am going to take a closer look at most of our radiator vents this weekend. Please correct me if I am wrong but I am assuming if the whole radiator is hot, then I shouldn't get that gargle right or any hissing for the matter because its closed? If its say 1/2 hot the gargle and or hissing is normal? Would you guys have any opinion roughly how long it should take a normal radiator to get hot enough to close its vent?

Fred

@midiman143, in reality there should be no gurgle. That is an indication that there is water near the vent or maybe the vent is water logged. In that case, make sure the radiator is pitched back towards the supply valve.
The hissing really shouldn't be there either. You might hear a mild flow of air but the kind of hissing I hear on that video suggests that the system pressure is well over what it should be or that you have the vents open to the max, which should hardly ever be needed, except maybe on a huge radiator where you want a lot of heat. On those Hoffman 1A, setting 3 or 4 should work fine.
There is no defined amount of time for a radiator vent to close. By the time the last section gets mildly warm the vent should be closed.
AGAIN, THE HISSING PROBLEM WILL LIKELY GO AWAY WHEN YOU HAVE YOUR MAINS PROPERLY VENTED. WHAT IS HAPPENING NOW IS THAT THE RADIATOR VENTS ARE TRYING TO PUSH ALL THE AIR OUT OF THE MAINS, THE RADIATOR RUN-OUTS AND THE RADIATORS. THOSE MAIN VENTS YOU HAVE ON THERE NOW JUST DON'T HAVE THE CAPACITY TO DO THE MAIN VENTING AND THE RADIATOR VENTS WEREN'T DESIGNED TO HANDLE ALL THAT AIR.

MilanD

@Fred that's quite interesting. I have 1a vent like that in my office on a small rad. I hear it gurgle just like that only when the whole rad is hot, and I run 4 oz for the most part of heating cycle... Whacking it with something firm like a key chain or my ring finger would then stop the gurgle and the vent would stay closed. I'm 100% positive my vent does this very thing from time to time. I did have a shooting Hoffman 40 on a waterlogged rad with a stream shooting 5 feet in the air, but never 1a so I can't say what it looks like if water shoots out of it. But, when steam hits it and it doesn't close, not being waterlogged just failing to close on otherwise functioning and pitched rad, sounds like the video. Air coming out before steam gets to it is inaudible. Once steam gets to it, it gurgles like what's in the video. I call that a gurgle: kind of a wet sputtering.

At any rate...

Fred

@MilanD I have Hoffman 1A's on all 15 of my rads and not one of them ever gurgles. A few did at one time and it was always remedied by re-pitching the rad. They hissed once upon a time when the pressure was out of control and when I only had one Hoffman 75 on each main.

midiman143

@Fred , maybe I will try and pitch one as an experiment where i have two that gurgle. I will try the pitch where it is "cracking the bubble" as I read on this forum on the topic. Stayed tuned and we will see if the pitching affects this issue along with the main vents.

@MilanD - thank you for sharing your experience which is remarkably similar to mine.

BobC

It must be something in the way the system is laid out. My 2" steam main circles the chimney so it's only about 12 ft long. As a result the runouts to radiator risers are 12 to 15 ft long.

About 7 years ago I bought a 6 pack of Hoffman 1a's and put them on all the radiators but the bathroom which had an ond Ventrite on it. All the hoffmans spit and would only seal if I rapped them with something. I went over all the pipes and checked the pipes for slope, the boiler is set to cut out at 12 oz and back on at 4 oz. The boiler is oversized so it does cycle some before the thermostat trips.

I tried a Maid O Mist on the bedroom rad and that solved the problem, I then replaced all the Hoffman's with MOM's and everything is happy. So now I have a bunch of hoffman's sitting in a box along with one spare MOM.

Bob

midiman143

Update #2
Hello Everyone,

Again I want to thank everyone for their insights and shared experience. So it does appear as though 90% + of our issue seems to have been due to the main line vents. We replaced the vents on the 31st, had to refill the boiler on the 5th, but since the 5th we haven't had to replace the water at all and the water level seems to be staying steady. The running PSI is normally low like before and I have seem only 2 spikes of pressure, one above 1 PSI and one about 2.75 PSI. Both were after a long run time of 20+ minutes . As anyone knows in the north east we had a hell of a cold steak about 2 weeks ago and those long run times were mostly due I think to the outside temperature being in the single digits. The vents do still "hiss" but not as gurgling as before and they tend to close now which is really nice. I did not adjust the pitch of the radiator vents yet or check for other leaks as I wanted to see how this worked out first. I do plan to buy a blood pressure gauge and check the pressurtrol to see how calibrated it is and if it working correctly. I dont think it is due to the boiler seemingly never being shut off due to pressure but it would have to get up to 1.5 PSI if the pressurtrol is accurate. Any feedback is always welcomed. Thank you again for everything

-Paige

MilanD

That's great on stopping water loss - I am also surprised how much water a boiler can lose from the main vent or the rad vent. We have some 30 radiators and 3 mains, a total of 5 main vents (3 big mouths and 2 Hoffman 75). I walk the premises every few days to see if any of the vents is hissing/leaking. They are not, but, on these cold days when boiler is on a lot, I easily go through about a gallon every 2-4 days... I've discovered since my last post here, that my Big Mouths tend to puff a bit before they close, but I'm for now will not ask for a replacement disk... they do close eventually. At any rate ...

To your pressuretrol calibration: All you need is a good 3 psi gauge on your boiler controls arm, and then watch the boiler run when the pressure is building. Once it gets to the pressure you want cutout to happen and it ptrol does not cut-off, you can use the set screw inside the ptrol's pressure push arm at the bottom of the inside of the trol, to calibrate cut-out pressure... There is a blue lock-tite you'll have to scrape off, and you'll need a small allen wrench - i believe it's 1/64 or 1/32... it's really a small one. You do righty-thighty to screw it in and this should lower the cut-out pressure. Be careful not to push the screw all the way through as it can fall out.

If you want to run even lower pressures, getting a 16 oz vaporstat might be the way to go, but how well that works will depend if the boiler is properly sized and if you in fact can get rads hot properly for the given outside temperature without building the pressure first. You have an oil boiler, right? I have no experience with oil so can't comment on benefits of running on slightly higher pressure vs. cycling on lower pressure on oil fuel.