Hoffman Bear Traps

the_donut

Has anyone ever put a big mouth on the high side inlet to increase the venting of these traps?

Two pipe steam. I've got about 200' of 6" per main (2 branches total) and these traps seem to be the bottleneck. Headroom is a little tight along the piping and there is quite a bit of asbestos insulation I don't want to disturb.

Jamie Hall

Where are these traps? Are they crossover traps (ends of mains to dry returns?). If so you don't want venting there, but there would be no harm to piping any steam trap - such as a Big Mouth -- in parallel (that is, side by side) with the existing ones.

Steamhead

What size and model is this Bear Trap? Assuming the branches are evenly split at 100 feet each, you have 20 cubic feet of air to vent from each branch. So the bigger the pipe size of the existing traps, the better.

the_donut

IIRC the traps are FT015H-3. They are placed at the end of the 2x 200' 6" mains. The are connected to a 1-1/2" verticle drop that elbows into a pitched downward return about 20' into the receiver of a bfp. The receiver is vented via 1-1/4 pipe.

System runs on pressure currently. I want to hook up indoor sensor to controller instead. Issue is system vents primarily through radiators and unevenly. I plan on slowing radiators down by installing orifice in shutoff valve, but I would like to increase venting on the steam mains as the traps vent slowly (0.950 cfm @ 3oz).

I was wondering if the FT015H-3 inlets are connected inside trap body. If so then I could simply plumb an elbow up out of top of trap and make an antler to vent instead of removing insulation and tapping (something I wouldnt want to do knowing the history of this building).

Steamhead

They are connected inside, and so are the outlets. So you can actually install a high-capacity thermostatic trap- or a manifold with several such traps- as a bypass to the F&T, directing system air toward the condensate receiver vent.

We've used Nicholson high-capacity traps to do this, but the B&J Big Mouth crossover traps are much easier to get. These are available in 1/2" and 3/4" sizes, and IIRC the throughputs are the same.

the_donut

@Steamhead
Do you plumb inlet of bear trap -> crossover trap -> outlet of bear trap or inlet of bear trap -> crossover trap -> and tie in to line to receiver? Would their be any cons in just venting to atmosphere before the trap by plumbing a couple of big mouths in an antler connected to top of inlet?

I like the prospect of tying into vent line to keep vacuum without having to modify the big mouths.

Steamhead

Either way will work. I prefer discharging the Big Mouths into the return since that will avoid the problem of water spillage in case the system floods. And it would also allow for vacuum operation, as you say.

Sailah

Barnes & Jones will make you a crossover trap designed for normal crossover trap replacement. Same capacity, but the O ring is replaced with a brass seat. Needs to be ordered directly from factory.