Hissing and Spitting Air Valves

Eagle1017

Hi - I've got a single pipe steam heating system. The house was built in 1941. There are 10 radiators on the system. I just moved into the house and when I did I converted from oil heat to gas heat. I've got tenants that live upstairs who are in the house 24/7 so I need to keep the heat on at all times. I've got the thermostat set to increase the heat early in the morning. Whenever the heat comes on (after about 20 minutes into the cycle) there are 4 radiators on the first floor (the floor we live on) on which the air valves (heat timer varivalves) start hissing. This happens as the radiators heat up and get close to the final section. Once and a while the valve spews rusty water all over the hardwood floors. I have all the radiators pitched back towards the pipes and to the best I can tell all the main lines pitch back to the boiler. There are two main air valves in the basement where the main steam line meets the main return lines. I have the pressuretrol set to 2 psi with a 1.5 differential (subtractive). When the system is on the water level drops close to the bottom and when it comes back on the water level is well above half way - there is automatic water feeder. It seems like a large amount of air is coming out of the varivalves - could this be a main valve problem? Why would water be coming out of the one varivalve if I have it pitched back toward the pipe? Do I have a condensate problem? Appreciate any insight.

KC_Jones

Start by lowering the pressure as low as you can get it. 2 psi is on the high side for steam 1.5 or lower if possible. How much temperature setback are you using at night?

David Nadle

I can't see from the pictures how you're supposed to skim that boiler. Was it ever skimmed? I would start there. There's probably a water quality issue causing wet steam.

Eagle1017

Thanks KC_Jones and David. If I lower the pressure won't the boiler kick off when I haven't reached the temperature I want? The issue is the couple renting upstairs are elderly and need it very warm. There is only one zone and the thermostat is on my floor. I have it set at 71 at night and 74 starting at 5AM. I need it to be set that high to get the temperature up on the second floor to 68-70 degrees. If I lower the pressure the boiler will switch off and it won't get warm enough upstairs.

I'm not familiar with skimming the boiler. What is that? What is "wet steam". Water spewing out of varivalve is very rusty.

Thanks again.

Mark N

Could be a couple of things. One thing I notice is all the main pipes are uninsulated. He is using setback, uninsulated pipes makes for a lot of condensate. Pipes go stone cold over night. It looks like he is also using straight shank rad vents as main vents. Are the radiator valves completely open?

KC_Jones

Pressure will not get the steam to the second floor. If you are having trouble with that you have a venting issue. The lower the pressure the better the steam moves. Yes it will kick the burner off, but once the pressure drops it will kick back on again until the thermostat is happy. It sound like you need to address your venting. Also I agree with David if this boiler was not skimmed that could be a problem as well. You are probably surging. Read the attached article tons of good information. There is a section about skimming. This procedure HAS to be done on any new install or you will never get it running correctly.
https://heatinghelp.com/systems-help-center/a-steam-heating-primer/

Abracadabra

Replace those "main vents" They are not true main vents, more like vertical radiator vents. I'm pretty sure they are something like this:

http://www.supplyhouse.com/Gorton-G5S8-Gorton-No-5-1-8-Straight-Vapor-Equalizing-Valve-3530000-p

You need way more main venting. Also, insulate your mains.

If there an aquastat on the return line anywhere that cuts off the boiler or is the cycle only controlled by the thermostat?

Varivents are prone to spitting if there's wet steam and high pressure. Sounds like you have both.

Eagle1017

Thanks Mark N. Yes the main vent valve is a Gorton D. The radiator valves (assume you mean valve where pipe connects to radiator and not varivalve air valve) are open except for one radiator in the room with the thermostat - when the new boiler went in about 2 months ago the plumber also replaced the valve and that one stays shut - otherwise the thermostat would react to quickly to temperature. Should I insulate main lines?

How much is typical to get a plumber to skim the boiler? If its a brand new boiler why would it need to be skimmed?

Eagle1017

KC_Jones - what do you mean by address my venting? Do you mean set varivalves on first floor to closed to push steam upstairs?

KC_Jones

It needs to be skimmed because it's a new boiler. There are oils inside the system from manufacturing and new piping cutting oils from threads etc. That all needs removed and can ONLY be done properly with skimming. We don't talk about pricing on this site so can't comment on what they might charge. Honestly in my opinion it is DIY friendly if you feel so inclined. That is if they installed the skim port, which if they didn't skim they might not have done. A Gorton D is not even close to enough venting that is why you are having trouble getting the steam upstairs as is the insulation. You should insulate every pipe you can get to in the basement. How long and what size mains? The rule of thumb is 1 Gorton #2 vent for every 20' of 2" main.

KC_Jones

Eagle1017 said:

KC_Jones - what do you mean by address my venting? Do you mean set varivalves on first floor to closed to push steam upstairs?

Your mains don't have enough venting for sure. Once you get the mains corrected you can control the individual radiators to balance out the system. You want all the radiators to get steam at the same time. A general rule would be to vent the downstairs a little slower than upstairs. This is because you need to get all the air out of the pipe going to the upstairs radiator in addition to the radiator itself.

David Nadle

A wide open varivalve is one of the fastest vents available. You want to have faster venting in the mains and slower venting on the radiators. You need to be able to skim the boiler, and you should insulate all the near boiler and main pipes. There are some things you can try right away that may help. Turn all the first floor vents down to the minimum, and stop doing the setback. You may ultimately have to choose different vents for both the mains and radiators, but I wouldn't do that until you have the steam quality issues addressed.

Mark N

Steam mains absolutely need to be insulated.

Eagle1017

The main lines are 2" and there is about 40 feet. Will a #2 Gorton fit where the Gorton D is? Or would I have to make cut to the main?

BobC

All of the comments are correct but I'd like to add something about the varivents. they do not have a float so they can spray water. They are also an aggressive vent because people tend to run them towards full open. You might be better off with slower vents like a Gorton 5 on the first floor.

The mains need to be vented fast, the D you have now may not be fast enough. How long is the steam main?

Bob

KC_Jones

if you have 40' of main you are going to want to do 2 Gorton #2 vents. There is a busing in that fitting that the Gorton D vent is in that bushing will need removed and you will have to build a vent "antler" to install 2 Gorton #2 vents. I can't tell from the picture what size the busing it, but it appears to be 3/4" pipe at least.

David Nadle

If you can get those reducers out you can replace with 1/2" and install Gorton #2's.

Eagle1017

Thanks all. I'm going to purchase 2 #2 Gortons. Where is best place to find them? I'm in Queens NY. Not sure I know how to build a vent antler. Anyway I can just buy a screw/bushing that will go into a 1/4" bushing and accept the 1/2" Gorton?

KC_Jones

No you need to remove the bushing that is there. 1/4" is too small of a hole to vent through. If you do a search of the wall you should be able to read a little about vent antlers and see some pics. Here is a link to one someone made recently and some information about how to do it. How you build it depends upon your house and available space, but it looks like you have a decent amount of space.
http://forum.heatinghelp.com/discussion/comment/1351957#Comment_1351957

David Nadle

If those vents are 1/4" and not 1/8", I think it's worth a try to use a 1/4" to 1/2" adapter and a single Gorton #2 on each main. An open 1/4" pipe is faster than a single #2. But if you want to add multiple vents per main you'll need to get those old bushings out.

Eagle1017

Ok thanks KC_Jones. See picture. Can I just get a bushing that has 1/2" opening? If so why would I need to build antler? Where do I get bushing?

Eagle1017

Thanks David. Any idea where I get a 1/4" to 1/2" adapter? Home depot?

KC_Jones

First you need to verify what thread you have. Those vents come in both 1/8" and 1/4" threads. If it's 1/8" you definitely need to take the bushing out. If it's 1/4" you could adapt up to a single Gorton #2 with a reducer coupling (1/2" x 1/4") and a 1/4" nipple. You need to verify what thread is actually in there first that vent is available in 1/8" and 1/4". If it's 1/8" you definitely need to remove the bushing. Judging by the picture it is 1/8" thread, but that is hard to tell in pictures. The reason I mention an antler is because by the general rule of thumb you will need quantity 2 Gorton #2 vents. The only way to mount that many is with an "antler". I attached a couple of links one is to the Gorton website showing the D vent in both threads and one is to a good article about balancing steam systems and is shows a picture of a vent antler.
https://heatinghelp.com/systems-help-center/balancing-one-pipe-steam-systems/
http://www.gorton-valves.com/_d_1_4__vertical

David Nadle

Eagle1017 said:

Thanks David. Any idea where I get a 1/4" to 1/2" adapter? Home depot?

supplyhouse.com/Ward-FBCO1-2x1-4-1-2-x-1-4-Black-Coupling-558000-p

plus as long of a 1/4" nipple as you can fit. You can order the vents from this site too.

Eagle1017

David and KC - the heat just cycled on and again lots and lots of air coming out of all varivalves. I went down to the existing main valves (Gorton D's) during this - not a sound. Why wouldn't I hear air coming out of them? As I mentioned before there is one on the east side of house where main steam valve meats main return line and one on the west side of house where main steam valve meats main return line on that side of house. Why is all the air in the system being pushed to the radiators? Why is there so much air in the system to begin with?

BobC

Were the main vents hot? How long are your steam mains? Do those main vents ever work, could they have failed shut?

How far from the vent is the radiator that is blowing air and what pressure is the boiler working at?

Bob

David Nadle

If the D's are hot they should be closed, and therefore quiet. Why wouldn't there be air in the system?

All the vents compete, until contact with steam causes them to close. If you increase the venting speed of the mains and decrease the venting speed of the radiators you won't hear the radiator vents.

Eagle1017

David - The D's are hot. So the Gorton #2's don't get as hot as fast so they allow more air to vent? Just seems like a lot of air - and I could be crazy but it seems like the air coming out of vents mimics the wind outside.

BobC - the mains are about 15 feet long and 25 feet long. The radiators that are blowing the most air are about 8 feet from one of the main valves. The pressuretrol is set to 1.5 main and 1.25 differential (subtractive). All air vents on the first floor at some point make lots of noise releasing air. I've never heard the D's on the main vent make a noise.

Mark N

I never hear any of my Gorton's vent any air. If you can hear the vents you don't have enough venting. Slide the adjustment on the varivents all the way closed. All the piping, all the rads, and the boiler above the water line is filled with air in between cycles. The vents are open to the atmosphere, so the air vented on each cycle reenters when the boiler shuts down. Hold up a piece of tissue to the vent port on the Gorton's, if they are working the tissue will flap around by the air being vented.

KC_Jones

For the sake of argument if you hear any vent making noise you have a lack of venting capacity in your system somewhere. And to correct my previous post on your mains I misunderstood what you said. 1 Gorton on each main should be sufficient. The way I read your previous post was you had 1 main that was 40' apologies for that.

Eagle1017

Ok thanks KC_Jones. I've ordered two Gorton #2's and am going to buy the bushings locally. Hopefully this helps! Thanks for help.

BobC

I suspect your pressure is higher than you think, pressuretrols are not always accurate. I would start by doubling the amount of main venting and turn those varivents down low. Does the water level bounce around a lot when the boiler is making steam?

You should have a low pressure (0-3 PSI) so you know what pressure your operating at

Eagle1017

Thanks BobC. Yes, the water does bounce around alot and when the heat cycle stops the water level raises a good amount - so when heat on its below half way and when heat cycles off it is well above half way. Its a brand new boiler and new pressuretrol so I hope it is working correctly. Is there a way to see the actual pressure or do you just use pressuretrol to keep you in a range. See my first post for picture of boiler and controls. When you say turn the varivents down do you mean to closed?

BobC

Has that boiler ever been skimmed? New boilers installations usually introduce oils into the system and that oil causes your waterline to become unstable. It takes a nice slow skimming session to get that oil out of the system. That boiler should have a skimming port on it, if it doesn't I'd call the installer and ask why one was not installed.

The 0-30 gauge that comes with the boiler is pretty lame when it comes to reading a pressure level of one or two PSI. A 0-3 PSI gauge should be installed beside the pressuretrol so you can see the pressure accurately.

Turn the varivents down till they are almost off and consider adding more main vents - I think you need more venting capacity.

Bob.

Eagle1017

BobC, KC_Jones, and David - my plan is to install the Gorton #2's on the mains, lower the pressure and potentially skim. In the meantime (before the #2's arrive) I've got an additional question. Last night the system cycled on about 3-4 times an hour. The air hissing out of the air vents was loud as usual and hopefully the new venting plan will work. But, when the system cycled off the radiator and radiator line in the basement (the line from main to that radiator) had some serious water/steam hammer. Very loud bangs every 2-3 minutes while the heat was cycled off. Yesterday I raised that radiator to create more overall pitch on the radiator line to the main while also making sure the radiator itself was pitched back towards the valve/pipe. Any ideas on how I can stop this water/steam hammer? Could I have raised the line too much?

Mark N

What kind of thermostat are you using? Also is it properly set up for steam. If it is a Honeywell should be set to 1CPH(cycle per hour). What was causing the system to cycle last night? Was it the pressuretrol? Check the pitch of the runout to that radiator. Don't over pitch the rad toward the valve.

KC_Jones

One general tip to the OP. When addressing pitch and water hammer issues, make the changes subtle. Don't make a whole bunch of changes at once because it makes it difficult to diagnose. Make one change give it a day or 2 then if that doesn't work try something else. Tuning these systems can take some time, but as long as you are patient they can be made to run very nicely. Your water hammer issue could be related to wet steam or pressure being too high not necessarily a pitch issue. Careful raising a radiator like you did, you want the main pipe pitched towards the end were your main vent is. It's fine to get the pitch correct on the radiator pipe, just make sure you didn't disturb the pitch on the main.

David Nadle

I don't think you're understanding the importance of clean water in the boiler. You can't "potentially" skim. It's an absolute must. And you should do it before anything else. Until you have good steam quality you will never eliminate the hissing and spitting vents.

Eagle1017

I'm using a Honeywell. I don't think it has a cycle setting - it goes on/off with 0.5 degree changes. The temperature made it cycle last night. I bought a lux thermostat which is coming in the mail. I bought it because it has a swing setting which will reduce the cycles.

I don't know how to skim the boiler. I will call plumber. If I completely drain the boiler will that do the trick? If so how do I do that? There are two spigots on both sides to drain boiler not sure the difference.

David Nadle

Honeywells have a cycle per hour setting. It should be set to 1 CPH for steam. You don't need to replace the thermostat.

Draining the boiler will not work. You need to skim the oils off the surface. There's lots of information on this site showing how to do that and why it's important.

Mark N

What model is your Honeywell thermostat? Do you have the manual for it? Most thermostats come set up out the box for forced hot air heat, which is 6CPH.