Bad Trap...?

RoiiRaz

Dear Pros,



I live in a 1920 house in Providence, RI with a 400k BTU Burnham (likely oversized - the house has ~3200 sq ft). I've been studying the system for the past few years. I've been enjoying "We Got Steam Heat" (which my 12-year-old took from me and started reading as well) and "The lost art..." I'm trying to diagnose some problems and have a few questions:



Question #1: Any recommendations for steam pros in my area?



My system is a one-pipe with two mains and a Barnes & Jones T43 F&T trap at the end of each dry return -- needed because we have a boiler-feed pump with a receiver (probably because of the lack of vertical clearance between the returns and the boiler -- less than 6 ft from the return to the floor).



My most pressing issue started with hammering and water squirting out of the last radiator on one of the mains. It was intermittent at first, but got worse recently. My diagnosis was a clogged trap, because the trap on this main was barely warm while the one on the other main was hot. I figured I'm stuck with a lot of condensate which wasn't moving along. I bought the T43 repair kit and took apart the trap. Indeed, found a LOT of rust chips inside. Cleaned it out, but could not figure out how to remove the float arm and valve even after removing the two bolts which connect the anchor plate of the floar arm to the trap body (and the vent too). I ran the boiler with the trap open to verify that my return is not blocked. I did get condensate and eventually some steam. So, I cleaned it up, sprayed some water up the return with a hose to clean it out (it all drained back fine), and then closed it back with a new gasket.



Question #2: My T43 (see photo) does not look exactly like some of the images I saw online. Are there multiple versions of B&J T43 F&Ts? If not, how do I get that old float arm assembly out of the trap body so I can put in the new one? What about the trap vent? How do I get that out?



Question #3: I see no main vent on either of my mains. Is my trap meant to serve as the main vent in this configuration?



Question #4: I got a digital thermostat a couple of years ago which lets me set the swing value. I set it to 1 degree, figuring that with a slightly higher swing I would prevent short-cycling and save on pickup. The thermostat also shows boiler run-time per day, so I can make a change and measure. I recently dropped the swing to 1/4 degree to prevent strong hammering at night until I fix the trap issue. I found that this change significantly dropped the daily boiler run-time. Make sense? Is my theory about saving on pickup incorrect?





Many thanks in advance for any wisdom.



Best,

-Roii

Jamie Hall

Not sure about the fixing the trap

since I've never tried.



However, you should have main vents anyway.  As it stands most if not all of your venting is being done by the radiators.  The system will probably work better and be more even if you have good main venting; then all the radiator traps have to do is cope with that riser and radiator, and you can get better balance.

RoiiRaz

Where / how to add the main vent?

Thanks, Jamie. Where would I plug in the main vent? Do I have to open up the main somewhere / add a tee in order to fit it in?

Jamie Hall

Main vents

should, ideally, be a foot or two from the far end of the main.  If there never were any there, putting them in is mostly a matter of figuring the easiest possible way to do it!  There are several options...



one of the more popular is to find a handy spot where you can get access to the top of the pipe and drill and tap a hole for the nipple for the vent -- typically half inch pipe thread.  This assumes, however, that you can get access and that you have a drill that do the job and a tap.  Which I certainly don't have!  Of course, if you have a tame and fairly intelligent plumber, he or she might be able to help.



Another possibility is that if there is a T at the end of the main you might be able to extend off that.  If you do, be sure that the vent is, again, on a T -- not on an elbow right at the end.  The purpose of that is to avoid having stray water, if you have hammer again, slamminng into the elbow and bouncing up and damaging the vent.



A third possibility is to attach the vent to a riser or runout which is at the end of the main.  It will still count as a main vent so long as it is before any radiators on the riser of runout.  It is often easier to get into a riser or runout.  You might even find a handy union somewhere, which makes life much simpler.

RoiiRaz

Yes!!!

Hi guys,



Wanted to give you an update on this case which I thought was an interesting finding. I opened up my main F&T trap and found rust chips inside. Thought they were getting in the way of the valve. Cleaned it out and closed it back up. Things seemed better for a while, but the hammering came back. I bought a trap repair kit and took it apart again. Then I realized that the ball float inside the trap is a lot heavier than the one in the repair kit. I took the old one out, and pulled out the old valve, and then realized that the old ball float was breached and full of water, making it ineffective as a float. That explains the whole thing. I put in the new valve and ball float. The system is purring like a kitten now. It's great.



Hope this helps someone...



I do have another question in case someone knows: The repair kit came with a replacement thermostatic vent as well, but I can't figure out how to replace that part of the trap. The good folks at B&J are not returning my calls.

RoiiRaz

Got an answer...

B&J called back. That hex nut at the top is a cap which opens for access to the thermostatic element.