steam radiators are hissing loudly and spraying hot water/steam

mspsh31415

I have steam radiators.

I have replaced all of the vents but some of them are hissing very loudly and some are letting out so much steam that the room feels like a sauna.

It seems to me that there is too much pressure in the system (based on internet research)

I checked the pressuretrol and the MAIN was at 2PSI and the DIFF (subtract) was at 1.5PSI. I lowered the main to 1.5 but now the whole system will not start. When I turn up the MAIN almost to 2 it starts.

does this mean there is too much pressure in the system even when it is off?

what is my next step? Is there a way to tell the boiler to burn slower/lower? i have Burnham boiler.

thank you for your help

STEAM DOCTOR

We need pictures. In particular of the boiler piping. Try to stand back so we can get an overall view. How does the boiler water behave, when boiler is firing?

ethicalpaul

does this mean there is too much pressure in the system even when it is off?

No. there is no pressure above atmosphere in a residential steam system when it has been off for a few minutes

You can't tell the boiler to boil slower but you can make it boil slower but it is not really a user-modifiable thing usually

Include a closeup picture of your pressure control with the pictures that @STEAM DOCTOR asked for

mspsh31415

Any other pics?

mspsh31415

"How does the boiler water behave, when boiler is firing?"

Where do I see the boiler water? In the pipe in 2nd pic?

mspsh31415

Wheen the main is up and the boiler is on the water in the pipe is going up and down by about 5mm=0.2 inch.

STEAM DOCTOR

Water definitely looks dirty. Can you take pictures of the piping on top of the boiler? Stand back so we can get an overall look

mspsh31415

mspsh31415

https://forum.heatinghelp.com/discussion/comment/1870159#Comment_1870159

There is sediment in the pipe

STEAM DOCTOR

Piping does not look bad. Water might need a good cleaning for starts

ethicalpaul

I've seen worse. The hartford loop is MIA but none of the piping choices would cause steam to hiss

The addition of a low-pressure gauge on the pigtail along with the pressure control would tell the truth about what your pressure is.

As nasty as that water looks the pigtail could be clogged and "hiding" the actual pressure from the pressure control.

Waher

I suspect the pigtail is clogged and the pressuretrol is not seeing pressure beyond what air is trapped behind the clog.

Jamie Hall

On the boiler won't restart. Double check the settings on the pressuretrol. The main scale should be set about 1.7 psi with that control. The differential scale should be set at not more than 0.6 psi

mattmia2

sediment would sink, i'm pretty sure that is oil in the sight glass which will cause surging which will throw liquid water in to the system which can get pushed out the vents. if the water bounces around while it is steaming we can tell you how to skim it to get rid of what i really think is oil.

the hissing may be bad or missing or severely undersized main vents

since it is cycling when you play with the pressuretrol settings I don't think the pigtail is clogged.

109A_5

Some pictures of the problematic vents ?

The actual water looks clean to me, the bottom 1/3 of the sight glass. The other junk upper 2/3 (probably rust) may have been there for a long time and accumulated over time. So when the boiler is boiling the water in the sight glass only deviates about 5mm or 0.2 inch and no other violent level changes.

The pigtail should be verified that it is not blocked.

Does the gauge ever move when " hissing very loudly and some are letting out so much steam that the room feels like a sauna "

Skim port if you choose to do a bit of skimming to see if there is any residual oil is still in the system.

Looks like a Hartford loop to me.

patrykrebisz

radiator vents are notoriously unreliable. i got 4x of 3 major brands and within each batch 1 was not closing when steam would hit it.

"sauna" in your room = vent is not closing as it's suppose when hot steam hits it.

pressuretrols are mechanical devices that suppose to be calibrated but in reality ARE NOT. some, straight out of factory, are so whack that they don't work at all. the only way to make sure it works is test it on a bench (basic Y split with 1-5psi gauge on one end and a small hand pump to intro pressure into the test device), then set it by screwing in or out a screw on the pressuretrol's back. yes, not working pressuretrol will send too much pressure down the pipes and in turn to the vents BUT working vents will shut in that steam in the radiators soon after steam heats those.

introducing steam too quickly into stone cold radiators will cause the steam condense too quickly. you want to insulate as much of your pipes as possible.

ethicalpaul

yep you’re right, Hartford loop is there. I must have been looking at a different thread just before this one

mspsh31415

thank you for all the ideas. in summary here are the possible problems and solutions:

1. There is oil in the system and it may need to be cleaned. (from @mattmia2) and the idea is to skim it. i can see the skim port but not sure what to do about it. however, it is not spraying oil it is steam.
2. There is somethign wrong with the pigtail (im assuming it is the small pipe under the pressuretrol). (from @ethicalpaul and @Waher and @109A_5) However @mattmia2 doesn't think it is the pigtail.
   1. how do i check it? do i need to remove it and manually clean it? can i do it myself or do i need a plumber?
3. Something is wrong with the pressuretrol. (from @patrykrebisz )
   1. how do i check this? it seems i need to disconnect it all and manually check it.
4. maybe the vents are not working properly (from @patrykrebisz )
   1. i will exchange working one with a hissing one and see. this seems like a simplest thing to try first.

asked for more info:

1. does the gauge move when heating. i will be able to check on sunday and let you know

i will have to check on sunday or monday and let you know

thank you all for helping

patrykrebisz

how to check pressuretrol:

https://www.youtube.com/watch?v=3AnN99dfxgY

https://www.youtube.com/watch?v=BLpuWRmwVmY

mspsh31415

just a quick update

1. i replaced vents and as someone pointed out they have high rate of failure. this fixed 3 hissing vents. the other 3 are still hissing even when i replaced them with a "good" one. so it seems that the problem is in the radiator.
2. since the system works well i do not think the problem is with the pigtail or the pressuretrol.
3. the gauge does move when the system works.

thanks to all for help

mattmia2

it won't "spray oil". The oil will cause it to surge, throw liquid water up in to the mains. That liquid water may get pushed out the vents. It will also damage the piping over time.

Jamie Hall

https://forum.heatinghelp.com/discussion/comment/1871905#Comment_1871905

On your comment 1. There is nothing in a radiator, It is a hollow chunk of cast iron — nothing more, nothing less.

If vents are hissing, there are really only two possibilities: they are defective or the pressure is too high. And, I might add, if the pressure is too high the vents will be defective very quickly.

Which goes to your comments 2 and 3. You are presuming that sincee the system works well the problem isn't with the pressuretrol or the pigtail. I beg to differ. Steam is, in some ways, oddly forgiving — and excess pressure is one of those ways. While it creates all manor of problems, what it does not usually do is keep the system from heating. Add to this that "the gauge does move" — if it is the normal 0 to 30 psig gauge, that almost certainly means the pressure is too high.

mspsh31415

https://forum.heatinghelp.com/discussion/comment/1871911#Comment_1871911

thank you for this.

so it seems that there is too much pressure but when i adjust the pressuretrol the system doesn;t even start because the reading is wrong. that means there is a disconnect between the actual pressure and the reading. that would suggest to clean the pigtail, check and re-calibrate the pressuretrol.

on the other hand the fact that the water level is "dancing" suggests that there is impurity in the system and it needs to be cleaned and skimmed.

can any of this be done by amateur?

Waher

@mspsh31415
To clean the pigtail:

Shut off the electricity to the boiler

Remove the clear plastic cover from the pressuretrol, label the wires with tape and take a picture with you phone so you know what wire goes where.

Disconnect the wires and armored cable sleeve from the pressuretrol.

Use a wrench on the brass nut at the base of the pressuretrol to unscrew it from the pigtail.

Stick the handle of the wrench through the loop of the pigtail to unscrew it.

Flush the pigtail with lots of water and make sure it passes water.

Pour boiled water into the elbow fitting on the boiler where the pigtail screwed in and make sure that elbow is freely draining, if it isn’t, use a coat hanger to clean it out.

Put new teflon tape on the pigtail threads clockwise and reassemble following the reverse of these instructions.

Adding a 1/4” brass union and hex nipple above the pigtail will allow you to avoid having to disconnect the wires next time by simply being able to undo the union nut to unscrew the pigtail. Wash all new piping thoroughly with dish detergent and rinse thoroughly before installing to avoid adding new oil (or soap!) to the boiler water. It may be a good time to add a tee for a low pressure gauge as well so you can calibrate your pressuretrol settings to be accurate to the desired operating pressure range. I’ll post a photo here later tonight of an example pigtail assembly.

Waher

The pressuretrol settings are an example of why one needs a low pressure gauge to get the settings correct because the Honeywell’s factory calibration is a joke. There’s no way I would have ever achieved .5psi cut in and 1.5psi cut out relying on the markings alone without a gauge to witness the real operating pressure.

mattmia2

others can describe skimming better, but essentially you heat the boiler to almost steaming then turn it off, remove the cap on the skim port or open the valve, put a bucket under it, turn on the manual fill just very slightly until a stream of water about the size of a pencil starts running out of the skim port and let that go in to the bucket for maybe an hour or 2. you can turn the boiler on and off to keep the water near steam hot, that will make it more effective. if it was throwing all that stuff up into the mains you will have to do it a couple times over a couple weeks as the steam and condensate brings that oil that the surging threw in to the mains back to the boiler. You are trying to float the oil on the surface out the skim port.

mspsh31415

https://forum.heatinghelp.com/discussion/comment/1871936#Comment_1871936

Where is the manual fill?

Is it where the water tube is?

Jamie Hall

Actually the OP's pressuretrol is the other type — not the one with the clear cover. But the principle is the same. Odds are it's the pigtail is clogged. they do that.

The only real caution is to mark — and possibly photograph — how the wires are connected!

The reason yours doesn't reset when you try too set it too low is just that — when you go to, never mind below, the bottom marking on the scale, that often happens.

mattmia2

this is the manual fill valve

HeatingHelp.com

Here are some troubleshooting tips: https://heatinghelp.com/systems-help-center/spitting-or-hissing-air-vents/

mspsh31415

new update:

First, thank you to all for your fantastic help.

1. I checked the pigtal - clean as a whistle. Also the elbow bellow is clean and water runs through it easily. When is stick a wire in it has a bit of goo on it.
2. skimming: I couldn't unscrew the skimming port so i opened the valve below and black water came out. When the flow slowed (stopped) I opened the manual fill valve. I kept it open until clear water was coming out. Closed both in and out valves and restarted the system to get it hot. Then repeat. I plan to do this a few more times. I assume that the water should be clean. Is there some chemical to use to clean it better/faster?

STEAM DOCTOR

8-way boiler cleaner

Steamhead

@mspsh31415 , what brand of air vents are you using?

mspsh31415

https://forum.heatinghelp.com/discussion/comment/1872547#Comment_1872547

PLUMBERS EDGE

https://www.homedepot.com/p/PLUMBERS-EDGE-1-8-in-IPS-Angled-Vent-Valve-PE884/300198967

Waher

Those Plumber's Edge vents are probably the worst quality vents on the market and they may simply not be working due to poor manufacturing standards.

Maybe try Maid O'Mist which used to be available at Home Depot (boxes still sometimes mixed in with the plumber's edge ones) and still are available from some Ace Hardware locations.

https://www.acehardware.com/departments/heating-and-cooling/thermostats-and-heating-supplies/radiator-vents/4065801

https://www.amazon.com/OMIST-0220-5L-Angle-Steam-Valve/dp/B003DV3AGE/ref%3Dsr_1_1?sr=8-1

https://www.supplyhouse.com/Jacobus-Maid-O-Mist-0220-5L-1-8-Adjustable-Angle-Steam-Vent-Valve-6-Piece

Otherwise Gorton or Vent-rite make good vents,

Steamhead

As did Hoffman, until they moved production to China.

ChrisJ

https://forum.heatinghelp.com/discussion/comment/1872551#Comment_1872551

I feel the caps on the Hoffman 1As were an embarrassment. The fit was so sloppy the numbers were completely useless.

gfrbrookline

Am I reading this wrong, I have a Pressuretrol subtractive I had it set at 2psi with a 1.5 cut out and I lowered it to 1.5PSI with a 1.5 cut out. So you set the pressuretrol to cut out at 0psi. You will never see steam at that setting. try 1psi with a .5 cut out. Your pressuretrol is likely malfunctioning based on your settings.

Jamie Hall

https://forum.heatinghelp.com/discussion/comment/1874107#Comment_1874107

Ah … close, but no. A subtractive pressuretrol has two scales. The main scale sets the cutout pressure — in this case, apparently originally 2 psig but rest to 1.5 psig. The differential, left hand scale, is subtractive, and subtracting its setting from the main scle gives you the cutin pressure. In this instance, apparently the differential was set a 1.5 psi, which gave a 0.5 psig cutin . However, the main scale was reset to 1.5 psig and the differential left at 1.5, which gave a cutin pressure of 0.

And that is the problem. A cutin pressure of 0 psig is, at best, unreliable, and with even slight errors in setting may not work at all. This, however, is not a problem with the pressuretrol, but is operator error. Sorry.

As a general rule, I would never set the differential pressure to more than half the main scale cutout pressure on a subtractive pressuretrol.