New Hoffman Vents Pop Open

Chuck_14

I recently replaced all of the radiator vents in my home, as well as the two main vents. Now all of the radiators will heat up, but I have noticed a new problem of course.

When my wife or I get home from work, we typically are bringing the house temperature up by about 6°. After the radiators heat up, some of the vents seem to stay stuck open. This is happening with the Hoffman 1A Adjustable Angle Air Valves that I bought, and to a lesser extent some of the leftover Dole 1A valves.

They are not permanently stuck open, however they seem to "pop" open/closed. They seem to be acting like a pressure relief valve. Some of these will stay open for minutes, while others just a few seconds. I have tried to check the pressure on the system, however I have never seen the pressure valve move. It sits at 0, and on a rare occassionaly I have seen it raise just off the needle during a firing cycle. I am worried the gauge is broken and that maybe the system is operating at a high pressure. Could this be the case?

The system seems to be fine when it is maintaining a temperature for the weekend, but not when it is trying to ramp the house up.

As usual, any information is welcome and many thank in advance.

P.S. Why does my steam system have a gauge that reads from 0-30 PSI when it should never operate above ~2 PSI? Why aren't these gauges scaled from 0-5 or 0-10 to give a little more precision?

Steamhead

That's normal

the steam goes into the vents and they pop closed, then it cools down and the vents pop open. The ones that stay open longer may be running a bit cooler than others, or it could be variations in manufacturing tolerances.

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David Efflandt

After the radiator is hot, it is normal for the vent to open momentarily if steam pushes more air into the radiator. But they should only release air (not steam or water).

If they pop open for awhile after the radiator is hot, it could be that the thermostat has turned off the boiler, and air is being sucked in as all the steam changes back to water. Do you have working vents on your steam mains, or only on the radiators?

will smith_2

Chuck- you can pick yourself up a better gage (0-5) and do away with that 0-30 paperweight. I have to guess that the reason that our manufacturers always put in the 0-30s is that they assume the boiler will be used for hot water.

Steamhead

No, the reason for that gauge

is that Code requires a gauge that will read twice the boiler's maximum safe working pressure. This has absolutely nothing to do with the system the boiler is used with. Most steamers are rated for a MWP of 15 pounds, which explains the 30-pound gauge.

To keep your boiler in compliance, install both gauges on a tee.

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