Radiator vents opening and spitting water

bherrick71

I have a single-pipe steam system in a 2 story house. There are 8 radiators throughout the two floors. I'm having issues with the radiator vents on the side of the house closest to the boiler hissing and spitting water at the end of the cycle. Here is the series of events:

• Boiler turns out
  
• Steam starts to move
  
• Steam reaches the radiators one by one and the vents close
  
• All of the vents are closed, but the house isn't at the target temperature yet so the boiler keeps firing
  
• Several vents on the side of the house closese to the burner start hissing and spitting
  
• Eventually the system shuts off
  

A few other notes:

• My pressuretrol is set as low as possible both on the cut-in and the cut-out
  
• I have a google nest, which came with the house
  
• I am pretty certain I have the right vents, and they're Gortons. All vents close at around the same (before a handful then open and make a ton of noise).
  

I am at a total loss as to how this is happening and what to do to stop it. It's waking us up at night. The mains are well-vented.

My theory is that the system is building up pressure after all the vents close and the extra pressure is causing the vents closest to the boiler to open. What can I do? Would a vaporstat with a lower cutoff threshold help? It's driving me nuts.

ethicalpaul

If I were betting I would say your pressure is higher than you think. Do you have a reliable low-pressure gauge on your boiler (in the range of like 0-3psi ?)

(edit) OR

Your venting might be too fast on your radiators (frankly it sounds a little like it--it should take quite a while--maybe 30-45 minutes or more-- for radiator vents to close against steam). In this situation, the steam races to the vent and closes it before the whole radiator is full of steam, then that steam condenses and the vent cools and reopens later in the cycle.

If the radiator venting is slow like it should be, the radiator will be fully steam hot (or nearly) before the radiator vents close.

JUGHNE

Do you have any vents on the steam main in the basement?

Has your pigtail loop been cleaned recently?

bherrick71

@ethicalpaul i think it's option 1--it definitely takes 30-45 minutes for the vents to get filled with steam and close. I don't have a reliable low-pressure gauge--just the pressuretrol. Come to think of it, I have a new pressuretrol installed a few months ago because they thought it was causing a problem. That's when this problem started. I think that's the issue--too much pressure and it's not cutting out due to the pressuretrol. It also seems like the most likely problem to me. Also, the radiators near fully piping hot when they close--I don't think they're closing early and cycling like you say. They're ripping hot when they're spitting.

@JUGHNE yes -- I have one at the end of each long run. I replaced one of them yesterday and they work great. And the pigtail was presumably cleaned in march when they replaced the pressuretrol but I'm thinking none of that works right.

ethicalpaul

It's hard to know if they cleaned the pigtail unless you saw it with your own eyes. Your description does sound like the pressuretrol isn't cutting out when it should...either due to it being messed up (there are a couple ways), or due to the pigtail being blocked.

Can you send a picture of a closeup of the pressuretrol face so we can see the setting?

SteamFTW

bherrick71 said:

...a new pressuretrol installed a few months ago because they thought it was causing a problem. That's when this problem started.

What signs did you have that something was amiss in March, which prompted you to have someone out to take a look? (Or was it just routine maintenance, during which with they brought a problem to your attention?) It might be helpful to know what they thought a new PTrol was going to fix.

bherrick71

@ethicalpaul I'll take a pic, but the pressure is as low as it goes and the cutoff is also dialed all the way down.

@streamftw alas, yes. There is something amiss with our ignition sequence. We spent $1,000 for a deep cleaning and a new pressuretrol which they thought would solve the problem of the boiler not lighting. It did not. (There is still something off--sometimes it doesn't light, but that will get figured out after this. Haven't had the issue yet this fall. I posted about this here a few months ago).

bherrick71

JUGHNE

There more complaints here with NEST thermostats than any other brand.

For steam, for the most part, you want to set the temp and forget it.

The Nest may have a mind of it's own as far as not starting the boiler.

What does the boiler do when it does not light, does it go thru the first steps of ignition and then no fire or does it just sit there quietly.

The problem could very well be the nest.

Show the pressure gauge, sight glass and all boiler piping around boiler.

How many wires are connected to the Nest?

neilc

what does your pressure gage get up to when the hissing and spitting starts?
the Ptrol seems to be set well,

I'm wondering if the Ptrol is wired correctly,
or if the nest wiring is correct?
does the Ptrol shut the boiler off at pressure setting?

If you shut off the boiler at the service switch, while thermostat is calling for heat,
and remove a wire from the Ptrol,
then turn on boiler service switch,
Does the boiler fire?
It should not with the wire removed at the Ptrol,

ethicalpaul

I like @neilc 's testing advice above.

Also I will say you can set the P-trol TOO low to where its behavior is undefined. Yours is really low (which is generally great, unless it makes your ptrol not work).

When you're firing your boiler for his tests above, also try to manually "help" the pressuretrol activate with your finger:

If you look at the mechanism, you should see how the pressure pushes a lever (that shiny silver part in front of your pic) that makes a microswitch "click" which then should cut off the boiler. You can practice with the boiler off to see if you can make it activate and hear it. Be gentle, at that setting it should take very little "help" to make it "click".

You want it, while firing, to click to cut off, then when you release it, the boiler should kick back on.

I also like @JUGHNE 's healthy distrust of the Nest, but no thermostat should ever be able to make your boiler run at too high a pressure (if yours indeed is...the best way to tell that is a reliable low-pressure gauge)

dabrakeman

Do you know if your boiler was sized correctly in the first place? Are you trying to do a significant recovery when this situation is occurring? If so you could try programming your Nest to break up the recovery into increments of not more than 30 minutes.
The pressuretrol could just be not letting the boiler cut back in when set at it's absolute minimum settings. Just as a test you could increase the set point just a tad and see if the problem goes away as far as not firing.

bherrick71

@JUGHNE i am certain it's not the nest.

@ethicalpaul when I trigger the ptrol with my finger, it shuts off. However, I have no way of know if it's actually calibrated correctly because I have no point of reference (gauge or other ptrol to try to active with my finger)

A plumber came over and said it may be a balancing issue, so we started there. Adjusted a few vents and, unfortunately, the problem persisted. I think the next best step is to install a low-pressure gauge. Is this something I can tackle myself? It seems fairly straightforward. FWIW the plumber didn't think this was necessary, but I think it would be good to have as a point of reference. I still think it has to be the pressure running too high--and this problem started AFTER a new ptrol was installed.

ethicalpaul

I would never have a steam boiler without a nice low pressure gauge. In fact I have a BUNCH of extra Magnahelic ones that are very good. They are easy to install, you just use a Tee fitting after your pigtail.

It's good that you can get your ptrol to trigger with the help of your finger...that indicates at least it is functional.

PS: no balancing issue should make your pressure go above the cutout setting on the ptrol. Only a faulty ptrol or a blocked pigtail could cause that.

neilc

or wiring misadventures,

but I also go with #check your pigtail

bherrick71

Looks like I have a weekend project! I'll report back once I have checked the pigtail and installed a low pressure gauge!

mattmia2

Someone before you could have damaged the vents running much higher pressure as well.

bherrick71

Very exciting weekend

Cleaned the pigtail (it was a little dirty) and installed a new one with some clearance. I also added a pressure gauge. I ran a cycle and at the end, the same thing happened to a lesser degree than before--hissing and steam coming out of a few vents. (It did come out of different vents this time, which is interesting but makes sense as I changed up the vents in an effort to get it more-correct.)

When this happened, the pressure was at just about 1.5. (See picture) My differential is 1 and my ptrol is as low as it goes. From what I've read, this is about as low as I can get on my system without a vaporstat.

I'm going to assume this is just the way it is and that I need to do smaller recoveries, 2 degrees at a time versus anything more substantial than that. And if I want more control, I need a vaporstat.

It is running better than before, though.

In summary, I think the issues were:

1) clogged pigtail
2) System was improperly balanced (and it's better but we're still getting there)

I appreciate everyone's help here. I love this forum. You all are the best.

mattmia2

Did we figure out that the main vents are adequate? Are the vents steam hot when they're spitting?

ethicalpaul

Looks pretty good and you'll get a lot of good info from that gauge.

I would maybe adjust your layout there a bit. I'd put the pigtail first coming out of the boiler. It will give the gunk less area to collect (the gunk after the pigtail is nil--it is all on the boiler side of the pigtail).

I'd also get a longer nipple between the gauge and the ptrol just so you don't have to have your ptrol sideways, and also to give you room to remove your ptrol if you need to. Although you shouldn't have to do that because with a setup like you have now, once a year you can just remove the gauge and then blow forcefully into the boiler to clear the gunky water out of the pigtail (if you do it once every year or two it won't have a chance to build up and solidify).

So maybe: Boiler -> pigtail -> elbow pointing up -> tee -> etc

Can you post a video to youtube showing your vents that are spitting? At that pressure and with decent, correctly-sized vents (Maid O Mist, Gorton, Hoffman), and radiators pitched correctly, you really shouldn't have any hissing or spitting (you might hear air rushing in at the end of a heating cycle as the steam collapses and a vacuum appears)

bherrick71

@ethicalpaul agreed on the room between the gauge and the ptrol - that'll happen when I have time to go buy a longer nipple. The pigtail came straight out of the boiler before but it was so damn close I couldn't rotate the ptrol at all to get it off. (you can see the scrapes on the boiler from it). It was one that was at a 90 degree angle, not 180 degrees (I don't know the name). I did it this way to get it away from the boiler a little so there was room to operate. I'll see if I can adjust this too, but I might leave it this way for now.

Here's the hissing. This is quite loud and comes out of a few rads. And again--this happens after all the vents close, the pressure builds up and forces a few to open again.

https://imgur.com/zjCU9fP

ethicalpaul

Thanks, that's a good video. It's hard to tell from here, but that sure sounds like more than 1.5 psi

I would say that vent has failed (is it a home depot or lowe's one?). Regardless replace it with a #4 Maid o Mist or Gorton (I get mine from supplyhouse, a proud sponsor of this very site). They shouldn't have any trouble holding back 1.5 psi

I get exactly what you mean about distance from the boiler, but you should be OK now with that straight-through pigtail you have now. I don't blame you for leaving for now but for now becomes 5 years real fast LOL

bherrick71

@ethicalpaul they're all fairly new gortons.

Would you recommend I replace all the ones making noise? I really don't think it's the vent's integrity but it might be the vent size. If they're screaming, should I go bigger or smaller?

ethicalpaul

The size shouldn't be related to the leaking. I would keep the size that works to give you the balance that you find appropriate for that room.

The size is determined by that little hole in the top...it is separate from the mechanism that closes to steam.

It would be very strange for gortons to fail at that rate. Maybe they got fouled by water/gunk either from overfilling the radiator or from surging?

KC_Jones

@bherrick71 could you elaborate on this?

"The mains are well-vented."

What brand and model main vent?
What size and length of main?

I only ask so we can make sure the radiator vents aren't venting for the main vents, which could cause excess noise in the right circumstance.

neilc

mattmia2 said:

Someone before you could have damaged the vents running much higher pressure as well.

Matt's quote is worth rereading,
you didn't answer what you were seeing as a high pressure prior to this weekends work,

it's possible that high pressure damaged the vents that are troubling you,
It might be worth picking up another (few) and trying a new one where your issues are, especially now that you have control of your pressure.

bherrick71

So much good information here! You guys are the best.

1) I don't actually know how high the pressure was running because I had no gauge. I will check it out next time it kicks on and observe when it happens and at what pressure.
2) I have a Gorton 1, brand new, and another one that I can't access in the walls (but I can sort of see it). It looks like a hoffman 76. I'm pretty certain these are adequate and a plumber confirmed it. I will go and measure and provide that info in my next update.

I live in NJ and it's going to be warm for a few days. I will let everyone know how it goes next time it kicks on and runs for a whole cycle. I may get impatient and crank the heat for diagnosis reasons before then, though.

ethicalpaul

Having disassembled Gorton vents, and having seen several more of them in Gordo's videos, I am at a loss as to how pressure at the level allowed by any residential pressuretrol could actually damage one.

But if that video is showing around 1-2psi with that steam leaking then something is definitely wrong with that vent.

RTW

I had the pigtail checked out the other day and was told while there were no obstructions, it should have water inside that connects to the pressure troll instead of just steam. Not sure if that is your issue but wanted to through it out there

Regards,
Bob

SteamFTW

Anti-PITA Tip: Put a union on the pigtail. Everything you see here, above the union, you can just move aside, check the pigtail, and then reattach the union. Cake. You no longer have to disconnect the wiring and spin the Ptrol off, which sometimes is impossible anyway, if it was installed too close to the boiler.

bherrick71

Update: Looks like it's bad vents. They're both Gortons and they're both a year or two old, tops. Very disappointing--especially because it's not like I've been running super high pressure. I have confirmed the boiler cuts out at 1.5 PSI. I have regular boiler maintenance, so I don't think my system is super dirty and gunking up the vents. However, the problem is solved. We'll see how long it lasts.

However, I now have a nice new low pressure gauge on my pigtail, everything works, and I know how to clean it myself!

ethicalpaul

Is there any chance that boiler water could have been pushed up into your mains and then into the radiators, fouling the vents? I also wouldn't expect gortons to spontaneously fail, especially in a group like that.

bherrick71

I suppose it's possible, but it seems unlikely to me. The water level in my boiler is right where it needs to be, per the plumbers who come and service my boiler. They also do all the regular maintenance, and the company is one that is recommended right here on this website. Doesn't mean they didn't make a mistake but seems unlikely to me. But maybe I'm wrong!

FWIW the two that failed failed in exactly the same way on different radiators and swapping them out for older ones solved the problem. As in the hissing was happening, then I put that vent on a different rad for the next heating cycle and had the exact same problem.