Another "Created Equal" on Radiator Traps

Montana14

I'm replacing old Radiator traps. Without getting deep into the math, can I be free to replace models without degrading performance?

Jamie Hall

Well…are these for radiators or crossovers? In that case, yes, pretty much. There are a few instances, such as very large radiators or very long and large mains, where size matters, but not many. On some old vapour systems the outlets may not be traps at all, but that is another matter entirely and rather rare.

I would ask, though — are you thinking of replacing the whole trap? If so, why? If the trap has failed, and many of them do after years of service, it is much easier (like hours of labour, not to mention cheaper) to accurately identify the existing trap and simply replace the innards. Tunstall or Barnes & Johes make replacement elements for almost everything out there…

EBEBRATT-Ed

For the most part yes. But one mfgs 1/2" trap may not have the same capacity as a different mfg although the difference will be small.

F & T traps also have different size orafices. For instance a 3/4" 15lb rated F & T will probably have more capacity than the same MFGs 3/4" 30lb rated trap

Steamhead

@Montana14 , what kind of traps do you have now?

The Steam Whisperer

You may want to do a search for Orifice plates before replacing radiator traps. They have a proven track record and have worked very well for us since we started using them about 20 years ago.

Montana14

I have a Dunham 2E. I know there is an insert for that. Client wanted the entire unit. My fault for offering. I can go back and pitch her again. Orifice plates? The washer-like insert? Not sure how that would help but now curious. My situation is that the steam is backing up the condensate end of the radiator. This is in one floor of an office building. Not the entire building which I do not control YET. Appreciate the help!

Jamie Hall

Steam is backing up from the condensate end? That's not your trap. That's another one on the same dry return.

Steamhead

Dunham is now MEPCO, and they make repair kits for those traps:

https://www.mepcollc.com/product/steam-repair/

No need to replace the entire trap.

ethicalpaul

https://forum.heatinghelp.com/discussion/comment/1852912#Comment_1852912

this is the insight.

What floor is your floor? Steam can’t back up from your trap—it condenses to water before it gets to the trap. Eventually when the whole radiator is steam hot, steam will get to your trap and close it but I think that’s not what you’re seeing.

Could it also be the trap in the basement @Jamie Hall or @Steamhead ?

The reason I ask is because it seems like it would have to be pretty far along the heating cycle for another radiator to get full of steam and fully heat the dry return before this radiator saw steam

Jamie Hall

"it would have to be pretty far along the heating cycle for another radiator to get full of steam and fully heat the dry return before this radiator saw steam"

You might be surprised…

Steamhead

@ethicalpaul said- "Could it also be the trap in the basement @Jamie Hall or @Steamhead ?"

Quite possibly. @Montana14 , are there any traps at the ends of the steam mains, piped over to the dry returns?

mattmia2

https://forum.heatinghelp.com/discussion/comment/1852979#Comment_1852979

if it is 2 pipe in a commercial building each room or apartment might have its own control and the boiler is always on.

Montana14

Let me catch up here. Looking into F&T downstairs. Original bucket trap there too. Each room has a thermostat so boiler continually runs. Heat is creeping into the last two ribs of radiator. Guessing trap has failed open.

mattmia2

https://forum.heatinghelp.com/discussion/comment/1853120#Comment_1853120

if the return end if the radiator is heating first than there is one or more failed steam traps elsewhere in the system letting steam in to the returns(or potentially some other system issues preventing water seals or equalizing devices from working properly depending on the exact type of system). there should be no steam in the returns and the returns should not be steam hot.

the return being hot while the radiator is cold isn't an issue at the emitter where it is happening.

Jamie Hall

As folks have been implying, you need to step back a bit and find out how steam — any steam at all — is getting into and, from the sound of it, even slightly pressurizing the dry returns.

In a two pipe steam system the dry returns should never see any steam at all, and should never rise above atmospheric pressure. They MUST, however, be adequately vented, and they themselves must NOT be trapped before dropping into a wet return.

There are a number of reasons why any of the above might be violated. Two of the more common are running at excess pressure, which will blow water seals, or having a new boiler installed with a water line which is too low, leading to a wet return no longer being wet. Double trapping is obvious, and needs to be eliminated. Inadequate venting — or venting missing completely — is also pretty obvious and needs fixing. There are other possibilities.

But your problem is not that one misbehaving radiator. It's that you have steam in the dry return, and that you must find and correct.

Steamhead

So, are you actually in Montana, @Montana14 ?

Montana14

Helena Montana

Montana14

This has been great. Big job ahead. Thanks! MT14

Steamhead

https://forum.heatinghelp.com/discussion/comment/1853164#Comment_1853164

If needed, you might be able to talk one of us into coming out there to consult.

JUGHNE

I ended up with upgrading a schoolhouse that has 2 floors and 2 pipe steam.

Main issue was steam coming out of the cond pump vent pipe…..to demonstrate the lack of steam knowledge in the area, someone installed a new pump and was surprised that that did not fix the problem. It probably was due for a new pump as it had "pumped" steam for quite a few years.

There were 3 steam mains with F&T's on each. These were hiding above a suspended ceiling and no one knew where and even what they were.

There were some bucket traps up there, of which I had never seen one in the field before. So upon learning that they are not a good trap for the application and needed to be primed every year I replaced them.

All the replacements were the standard 3/4" F&T's of common design with the double inlets and outlets. All F&T's got a wye strainer, with blow down valve, ahead of them.

On the extra outlet there was added a blow down valve for flushing and to check for steam passing.

On the extra inlet there was added a G2 air vent as it was a long run back to the cond pump and the "dry" piping had water traps. Also added a ball valve below each air vent in case it failed and passed water/steam. I am 150 miles away and could talk the part time maint guy thru shutting off the valve.

All the rad traps were changed, most new elements and some complete new trap.

And dropped the pressure from 8PSI to 3PSI.

Montana14

Bring your lighter tools. Horses get cranky on long, heavy rides.