Steam Trap maintenance and repair

Cloud_Pine

I'm slowly coming to grips with the intricacies of a steam system in a 90 year old house.

Heating season has become increasingly noisy here, with tapping, ticking and dripping sounds multiplying in the walls around the radiators. Though thankfully no water hammer sounds. My research indicates that faulty steam traps might be the cause, more specifically traps that have failed open and are allowing steam to escape into the condensate return pipes. Can someone please confirm whether this might indeed be the cause of these sounds?

Also should I be looking to open up every steam trap and replace all the mechanisms? I'm under the impression that these traps haven't been opened or maintained for decades.

Or should I just be focussing on those traps that don't exhibit an appropriate temperature differential between the radiator and the return?

Any tricks for safely removing seized caps? Applying heat with a propane torch perhaps? They all seem jammed tight and I'm worried about breaking them with the application of too much force.

Finally any recommendations for the best (and cheapest) replacement mechanism for these old Dunham Bush thermostatic traps? Picture include below.

Thanks.

JUGHNE

Do all the radiators get heat evenly......from the supply end?

Any traps that get hot with the supply valve off? Those may have failed open.
With the supply off the rad will be air bound and steam in the return may try to push thru the open trap as it compresses the air cushion.

To remove them, an impact driver with the exact 6 point socket will spin them off.

If the socket is just a little too tight, you can file the flats of the cap for a good fit.

I use a back up wrench on the trap body while doing this, perhaps overkill, but best to be cautious.

There are at least 2 companies that make replacements elements....Barnes & Jones and also Tunstall.

Jamie Hall

The best and only reliable way to test the traps is to check the inlet and outlet temperature when the system has been running long enough for the radiators to be mostly hot. A trap which is failed closed will be found by the radiator being much slower to heat than others, if it heats at all. However, there's a "gotch" on this: if there is another trap feeding the return for that radiator, and it is failed open, it may keep a radiator from heating. A trap which is failed open will be found by both the inlet to the trap and the outlet being steam hot -- I use an IR thermometer, but be sure to aim it at a bit of pipe with the same finish condition on both sides. A good trip will have at least a 5 degree temperature difference from inlet to outlet.

There is no "routine" maintenance required. Classic if it ain't broke, don't fix it. If the traps haven't been abused -- overpressured, usually -- they will last many decades If a trap is working, leave it alone.

The tapping and ticking noises are usually expansion of the pipes. It is remotely possible that a new set of such noises, appearing more or less suddenly, might be due to a trap having failed open, getting steam into its return, but that seems a bit of a stretch. A failed trap -- either way -- won't cause a water gurgling noise -- but a change in pitch due to something settling may.

Cloud_Pine

Maybe I'm off base in my thinking that the traps are failing, because apart from all the noises, the radiators seem to work fine.

I've been using an IR thermometer and there also seems to be a 5 degree differential between the radiator corners close to the trap and the return pipes.

I would sure like to figure out a way to quiet down those pipes though. I was hoping that it was something that I could fix.

JUGHNE

What pressure does the boiler run at?

Has the pigtail been cleaned recently and do you have a low pressure gauge, perhaps 0-3 or 5?

Cloud_Pine

The pigtail gauge seems like it might not be getting a reading because it is indicating no steam pressure at all when the boiler is firing and steam is circulating. See the photo.

There are a couple of pressure shutoff switches. But no other gauges.

Jamie Hall

The 0 to 15 psi gauge isn't likely to be very accurate at the low pressures (a few OUNCES per square inch) that your system should be running at. It is likely, in fact, that if steam is getting to your radiators and the radiators are heating your house that the system is working exactly as it should. Pressure is your enemy, not your friend.