Steam coming out of radiator vent

bwroga

Hello,
I set our thermostat at 65 during the day and 60 at night. When I turn the thermostat up in the morning on very cold days, the vent on one of my radiators will shoot out steam towards the end of the heating cycle after the whole radiator warms up. I'm assuming I should replace the vent.

It is a Vent Rite adjustable vent. This is the only replacement I could find, but it says it has a 1/8 inch connection. The little tube on my vent that screws into the radiator is more like 3/8 inch in diameter. Is this the wrong replacement, or am I missing something?

Grallert

Yes the 1/8 is the correct fitting. If I'm not mistaken and I really should know this, The inside diameter of the vent nipple is 1/8.

Jamie Hall

Check the cutoff pressure on your boiler -- it may be high enough at the end of a cycle to overwhelm a less than perfect vent.

bwroga

Thank you @Grallert and @Jamie Hall
The pressuretrol is set to between 0.5 and 1.5

bwroga

The pressure gauge on the boiler stays bottomed out at 0, which I posted about in a new discussion.

bwroga

I know the original post was from a year ago, but I finally replaced the vent

It seems to work, except the new vent now makes a whistling noise when the system starts up. Does this indicate a faulty vent?

When the system has been running for awhile some of the radiator vents that have been closed suddenly open and make a loud hissing sound and then after a few seconds close again. Does that indicate any problems, or is that normal?

ethicalpaul

Actual "whistling" is usually a sign of too-high pressure or lack of main venting (which forces more air than necessary through the small radiator vents instead of through the large main vents)

It is normal for vents to open and close during a long heating cycle. Some vents are more noticeable than others. But again if there's loud hissing, that points to too much pressure.

SteamingatMohawk

The outside diameter of 1/8" pipe is 0.405".