Why is this bad?

RPK

Condensate comes into header (red arrow). Condensate must rise to top of elbow (blue arrow) before draining into tank. Pressure is set low enough that even though the dry return fills with steam due to a building full of bad traps, the boiler cycles off before building enough pressure push the water through and blast steam out the vent (there’s a vent on the tank and a vent above that elbow (near the blue arrow). Green arrow is normal water line in boiler.

Apparently the system has run this way for quite some time without issue. I would think that blocking the vent with water would cause no heat or slow to heat areas because air can’t escape. I am told this wasn’t the case. We are just getting involved with this building and trying to sell the owner on testing/replacing or rebuilding all the traps. The owner’s “old-school” guys says this works fine if steam pressure is kept below 1psig.

JohnNY

I have to say your picture vs your description is confusing and I don't know what's going on there. However, when people tell me that there are no consequences to something that's obviously going to have consequences, I'm pretty well sure they don't realize what those consequences. Most often it's because they've lived with the conditions for so long they think it's all normal.

RPK

Here’s a sketch to clarify what I was trying to describe. Basically, there’s a water seal between the return and the condensate ate receiver. If steam pressure goes above 1psi, steam in the return pushes the water seal into the receiver and steam rapidly fills the mechanical room. My understanding is that having a water seal here will hinder air from leaving the system on startups and create a vacuum during off-cycles.

Potential issues I see:
Hindering air escape should result in no heat or slow to heat areas.

Vacuum formation may prevent proper condensate drainage.

Steam in return lines may cause water hammer

Slow steam distribution and cycling burner on 1psi increases wear on burner, decreases efficiency and may result in high fuel bill, and may fail to heat some areas.


Am I missing anything? It’s a hard sell rebuilding traps on vague suggestions of potential fuel savings when the owner is convinced everything worked fine last year with this setup. BTW, does anyone have any experience with the Tunstall capsules for Trane B-1 traps?

Full disclosure, we just installed a new boiler at this location. I’m not in charge of bidding jobs or installing boilers, just starting them up and servicing them.

nicholas bonham-carter

Those people would benefit from owning/reading “The Lost Art of Steam Heating”!—NBC

ratio

@RPK, I feel your pain. I too get to start up equipment that is nice and new but doesn't always solve the customer's problems or creates more than it fixes.

<sigh>

RPK

Well, does this sound like a good summary of why you should keep all steam traps in working order and not block the return vent with a water seal? Tunstall capsules are relatively inexpensive, so it’s not quite as hard a sell as I thought, but even so, landlords tend to favor the low bidder option.

RPK said:

Potential issues I see:
Hindering air escape should result in no heat or slow to heat areas.

Vacuum formation may prevent proper condensate drainage.

Steam in return lines may cause water hammer

Slow steam distribution and cycling burner on 1psi increases wear on burner, decreases efficiency and may result in high fuel bill, and may fail to heat some areas.