How does a Danfoss automatic vent work for one pipe steam system

Glen_5

I have several in my home (one pipe steam system). They work well, but I've found that in several rooms that don't need heat at all, turning them all the way down doesn't prevent the radiator from heating. There may be some adjustment somewhere, but the directions don't indicate any. If I remember correctly, the directions were minimal. On some rads with enclosures, I bought the valves with the remote sensor. They work well too.

Chris_102

How does a Danfoss automatic vent work for one pipe steam system

A customer of mine has a one pipe reverse flow steam system, and when he bought this house, he has a huge radiator in his kitchen (which is too large for the kitchen) so guys at my supply house told me to install a Danfoss 1 pipe steam valve RA2000 -1PS and I want to know how it works. I cannot find any directions online, and no directions came in the box. So if you can explain to me how it works that would be great! Thanks,
-Chris

Mark Eatherton

Soitanly...

Steam and air cannot occupy the same space. If you can't vent the air out of the radiator, you can't get steam IN to the radiator. The RA 2000 basically shuts off the air vent , disallowing the steam to enter the radiator and OVER heat the room.

As the room temp cools down, the vent is opened and steam enters the radiator, increasing radiator temperature. It is totally proportional. If you need just a little heat, it opens just a little bit. If you need a LOT of heat, it opens a LOT.

Personally, I think they should be MANDATORY on ALL one pipe steam systems.

Anyone want to argue the point?

ME

bob young

no bad reviews

they never really caught on in the new york area [ as far as i have seen ] but any one i know that has used them swears by them.

Brad White_198

Some Points

It is occasionally true that if you shut off the path to the air vent (which these valves do as their main function, intercepting the venting process based on room temperature), the radiator may still get partially hot or on average, tepid.

This is because air is compressible, as is steam. The steam will get into the radiator regardless, to the extent that it can compress the now-captive air. When the room cools and the valve opens, the vent is free to go! Of course, the vent is always open when the vent valve is closed for any length of time, you know that.

The other feature to look for is an integral vacuum breaker. When the room is satisfied, the thermostatic valve is closed and the vent can no longer serve to break the vacuum. It will be open but the radiator does not know that.

The integral vacuum breaker knows this and releases the condensate. Danfoss, Macon and Amaark (I can never get the right spelling down for that one), have this feature. Other brands I am not certain but they may be catching on.

Glen_5

Brad,

Your explanation solved that mystery. The compression of the air makes sense, allowing for partial warming. Other than that, I have to say that the valves work well.

Glen