Steam in wet returns

wildrage

Happy Thanksgiving, everyone!

Of course I have this issue when I have family over!

Those who know me, know my deal, but 1 pipe system, large house. A current known issue is that I need to drain my boiler and get some gunk out of it. Looks like maintenance guys after last season put some sort of detergent in it, and my water isn't clear.

I've been putting it off. I know, I know...it ain't getting any warmer, but things have been working fine.

So tonight I change the temp from 64 to 70 (I'm cheap, but family is over). Everything is working, radiators get hot, etc....however....something didn't seem right. Radiators hissing more than typical. Thermostat was calling for a bigger increase in temp, i get it, but i went down to check the boiler.

Noticed that the wet returns were pretty damn hot, and that a vent on the return was hissing, which I've never heard before. Seems like steam is getting into the wet returns, past the steam traps.

Note that its 12 degrees out tonight, so the call for a 5 degree bump made the system work harder.

Is this an issue? Any thoughts on possible causes?

Here's a pic of the vent that was hissing, on the wet return. This goes over to a condensate pump.

Thanks! Again, Happy Thanksgiving!

Jim

Fred

This is a one pipe system. What traps are you referring to? It sounds to me like the pigtail that your Pressuretrol is mounted on is clogged and the Pressuretrol can't see the system pressure to shut it down at about 1.5 to 2PSI. Take the Pressuretrol off of the pigtail (boiler powered down) and clean that out. Wet returns can get pretty hot from condensate return and especially hot from water backing out of the boiler due to excessive pressure. It is, after all boiling to make steam.

wildrage

@Fred Ugh that would be bad . I just dropped the thermostat so that the boiler cools off a bit to do that. Is there any way to test the Pressuretrol , other than that? It's supposed to be warmer on Saturday and Sunday, so I'd like to commence with the draining and refilling of the water then if possible. Water is getting darker .

Fred

Cleaning that pigtail out is not bad. If you are going to drain the boiler to get the chemicals out, just add that to your list. It only takes 15 minutes to disconnect the two wires on the Pressuretrol, take the Pressuretrol off and clean the pigtail (you can try to blow into it. That may clear it. If not take the pigtail off and use a wire to unclog it). It is a simple problem to fix.

EBEBRATT-Ed

So you may have a 1 pipe system if it is it sure isn't typical. Need some more pictures. The F & T trap in the picture could be the culprit. Are you blowing steam out of your condensate pump? Are the returns downstream from that trap excessively hot?

wildrage

EBEBRATT-Ed said:

So you may have a 1 pipe system if it is it sure isn't typical. Need some more pictures. The F & T trap in the picture could be the culprit. Are you blowing steam out of your condensate pump? Are the returns downstream from that trap excessively hot?

Returns are very hot downstream. About as hot as the mains. I have 2 returns, 1 short and 1 long, both have traps, and both are very hot downstream. Would probably be odd to have them both fail at once, no? Only seems to happen during a cycle that lasts more than say 40 mins of making steam....like when I turn the thermostat up 5 degrees on a day when it's 17 outside (like tonight).

Just watched it do a cycle to maintain temperature (1-2 degrees), and while the downstream returns were still very warm, i didn't have all the steam hissing out of the vents.

wildrage

EBEBRATT-Ed said:

So you may have a 1 pipe system if it is it sure isn't typical. Need some more pictures. The F & T trap in the picture could be the culprit. Are you blowing steam out of your condensate pump? Are the returns downstream from that trap excessively hot?

Hmmm...So I removed the Pressuretrol and blew in...probably not the best idea since the water is about 200 degrees :-P. Anyway, there was a tiny bit of resistance, but then i was able to blow and see the water level glass go up and down without much resistance. Hard to tell if there was a legitimate blockage, but atleast its not totally blocked (now atleast). I had my buddy Steamhead come in and replace the pigtail about 2 years ago, so its not that old, but still could have gotten gunked up. I'll take it completely apart this weekend when the temperature is 50 and not 20. I suppose the Pressuretrol could also be no good...it looks like its from the 70's. Are they known to go bad?

Thanks for your help everyone. Happy Black Friday now lol.

Jim

ethicalpaul

Pressuretrols are known to be inaccurate, seemingly always in the direction of higher pressures. You can add a 0-3 psi gauge somewhere to see what it’s doing, and you should be able to get it close. You can search here to find lots of old posts about them.

nicholas bonham-carter

When the boiler is recovering from such a large setback, it will tend to develop more pressure to raise the temperature.
Since you have a desire for economy, why not replace that main vent with some bigmouth venting, so you don’t have to pay the fuel company to force the air out of the system. That could shave off several minutes of firing time every cycle.—NBC