Short, loud hiss from air vents (pressure release?)

Geoff

I have a one pipe steam system with a programmable thermostat. Overnight, the temperature drops and in the morning, it is set to heat up 4 degrees F. This heatup takes about 15 minutes of continuous boiler firing and all radiators in the house get hot all the way across.

After all radiators are hot all the way across, the air valve on certain radiators (faster heating ones) make a short, very loud hiss, almost as though they were acting like a pressure release valve for the steam. This happens every 1-2 minutes and is very annoying and hard to sleep through. I have replaced the air vents in question but it still happens. The boiler pressure cutoff is set at 1 psi. My questions:

a) Is this normal - should radiator air vents release steam if the pressure is too high?

b) Anything I can do to avoid this?

tom_54

Try

using a smaller sized vent for those radiators. I have a similar problem. Instead of hissing when my radiator fills with steam the kind of gurgle. They must be bad. Theoritically the vents should close when steam reaches them.

BTW...I am impressed that you can raise the temperature in you residence 4 degrees in 15 minutes.

Patrick North

Me too!

Having the same problem- though this is with brand spanking new Hoffman A1's. In my case, pressure is maxing out near 4#. Yes, the boiler is oversized, close to 2X. Throttle back the pressure?
Thanks,
Patrick

Steve Garson_2

Patrick:

Lower the pressue to 1 lb if you can.

Steamhead (in transit)

They are cycling on temperature

they cool down enough to open, steam reaches them again and they close. This is normal. If it bothers you, switch to Gorton vents since they operate more quietly.

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Patrick North

That's ok by me- as long as it's not a sign of another problem, the sound is kind of nice.
By the way- from a Christmas party last night, this sight: a group of grown men oggling not the host's new car, big screen tv, ect., but his radiators. Now _that_ is the sign of a problem...
Thanks for the help,
Patrick

Unknown

4 psi!?

Patrick, what are u tryin to heat? 2/3 of Empire State Building? Bring the pressure down, way down! By the way, where are that group of men hanging out at the radiator? Sounds like my common men. Whenever there's a commerical with cutie baby or skimpky clad woman on it, I asked my lady, " Did ya see that radiator in the background?" She head for the phonebook..looking for heanding under "mental"...

Anna Conda

I have the same syndrome. We were watching an episode of "Torchwood" on Saturday. The main character was in a room in an old hotel, and I was staring at the radiator in the background, trying to see if it was one-pipe or two-....

Steamhead (in transit)

The party

was at your house, right?

Looks like we have some people up there who know what "makes" a house!

Regarding the system pressure- we cranked both pressuretrols down when I was there, but this type of control is not that accurate. I like Vaporstats that can't be set higher than 1 pound. If you got Vaporstats now, they could be re-installed on the replacement boilers.

P.S. Did your next-door neighbor get his steam pipes insulated yet?

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Patrick North

No, no parties at our place this year- we're still a bit of a construction zone (getting a little worse before it gets better). I do remember that you cranked back the pressure, but do you mean to say that without a Vaporstat they can't be fine tuned any lower than this 1-4# range, or just that the pressure gage itself isn't that reliable at that low a pressure? Sounds like it could be a worthwhile retrofit, especially if they won't get pitched when we get new boilers. Which, by the way, will be just as long as we can wait- we sold the house and, well- have you seen the market lately?

Steamhead (in transit)

The Vaporstats

would give you much closer control over the pressure. With a standard Pressuretrol it seems to be different on each individual unit. Go for it.

I take it the real-estate market up your way is sliding just as badly as in Baltimore.....

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Patrick North

Sounds good. And yeah- if it's any indication, the folks trying to sell their old place just down the street have now put their new house on the market, and are planning on moving back if it sells first. Ouch.
Thanks,
Patrick