danfoss valves and radiator issue


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Old 01-12-19, 08:30 AM
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danfoss valves and radiator issue

I have several radiators with danfoss RA2000 valves on them that are not heating up properly. I popped their thermostatic sensors off and confirmed that the pin is out and, can be pushed in. Last year I had this problem and replaced the thermostatic sensors and that seemed to help. But since they are only a year old I was reluctant to replace again. The building's super took a look and emailed me that the life spans for steam traps and valves are five years and they look like it's time to change them.

My questions:

- Do RA2000 valves really need to be replaced every five years even if the pin is not stuck and in the out position seems to let steam in ok (I can hear it hissing)?

- In a regular steam radiator with an RA2000 valve, where is the steam trap? Does it make sense that they need to be replaced every five years? What should I be looking for in determining whether it is ok, and is it something I can replace myself?
 
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Old 01-12-19, 09:03 AM
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More information is needed on the system, radiators and piping to even begin to answer your questions. A few pictures would help.
 
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Old 01-12-19, 10:10 AM
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This sight might give you some info. Do you have 1 or 2 pipe steam. These valves have nothing to do with traps which you will find on the return lines of 2 pipe steam rads.

As far as changing on a regular basis. My thought is why would you if they're working.

https://www.supplyhouse.com/Danfoss-...team-5551000-p

https://www.supplyhouse.com/Danfoss-...-Valves-789000
 
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Old 01-12-19, 11:31 AM
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Thanks. I attach pics of both of the radiators in question.

The first 5 pics show the radiator where I have the danfoss thermostat sensor removed. The last 2 pics show the radiator where I have the danfoss thermostat sensor on (on that radiator, I don't have easy access to the right side of the radiator so I haven't shown that).

These radiators are in the apartment building where I live, but I don't know the details of the system Based on looking at the radiator setup it seems like it is a two pipe system.

Where is the steam trap? Is it that thingie with a hex cap at the bottom of teh 5th pic? Does that require periodic maintenance? Would it be crazy for me to remove the hex cap (on a day when the heat is not on) to take a look?
 
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Old 01-12-19, 01:10 PM
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You do have a 2 pipe system which simply means the steams enters through 1 pipe and the condensate returns by another where as a 1 pipe system the steam and condensate use the same pipe.

That is the trap on the return line at the bottom of the 5th pic and they do fail and are rebuildable.
Below is a sight where you can get info and see your options. Yours looks like 1/2" but if it's 3/4" just put that size in the search bar. Type in steam traps for your options. They also have the rebuild kits, just need your brand. "Hoffman" for example.

https://www.supplyhouse.com/sh/contr...or+steam+traps

https://www.supplyhouse.com/Danfoss-...Radiator-Valve
 
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Old 01-12-19, 01:40 PM
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Thanks! Would you guess that if the danfoss valve pin seems to work (itís in the popped out position when I take the thermostat sensor off and I can depress it by pushing it down), I probably donít need to replace that?

Iím thinking that I should have a plumber replace the trap (especially because the trap in the second radiator isnít very accessible). But Iím curious: what does the trap do/how does it work? I donít see any vent so Iím not sure what it is trapping and/or separating from what. (Sorry if thatís an ignorant question.).
 
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Old 01-12-19, 02:09 PM
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This is just one sight but if you google "steam trap functions" you will get multiple choices. If you are really interested in steam there is a book by Dan Holohan called The Lost Art Of Steam which will tell you everything you need to know.

https://www.brighthubengineering.com...-a-steam-trap/
 
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Old 01-13-19, 04:10 AM
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Are the radiators in an enclosure or covered in any way? If they are in some type of enclosure or hidden in some way post a picture of the enclosure. In the top picture it looks like there are walls on both sides of the rads and on the bottom 2 pictures I see brick walls which are usually not shown as a finished wall.
 
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Old 01-13-19, 06:42 AM
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Yes, both radiators are enclosed and I realize that makes them less efficient. I tried to attach a pic but I am being told that I am over my attachment quota (and I don't see any way to delete my old pics or re-upload smaller versions to make room...I must be missing something simple). Anyway, the enclosures have generous gratings on the top and near the floor there is a decent slot for air to come in/out.

Despite the enclosures, when things are working properly (as they were a number of years ago), there's plenty of excess heat (I tended to need to turn down), and my other radiators seem fine, so I think something has changed.

I'm still stuck on what the building super said: that the danfoss valves (as well as the steam traps) have a five year life and probably need to be replaced. I get that the steam trap may need to be replaced or cleaned out (thanks for that link, spott), but does it make sense that I need to replace the danfoss valves even though their pins seem to work (they are in the popped out position when I take the thermostat sensors off and I can depress them by pushing them down)?
 
 

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