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