pressure too low w new main vents?

jimmythegreek

after alot of reading and expirementing with great help from you all I have made alot of changes to my 1 pipe steam system.  its a weil mclain EG95 400k plus btus steam, and 40+ rads in a commercial 4 story building.  Anyway I first got a low pressure guage, 1-3 psi and a vapor pressure guage 0-20 oz.  Upon installation I found the pigtail shut by dirt, and replaced all w brass and unions, I have my pressurtrol, vapor, 3 psi, and 30psi on a tree all unioned together.  system initially ran around 1 psi with 10-12 oz as an average.  after finding enormous debris in mud leg and skim tap leg, I cleaned and cleaned and cycled water and drained etc. for days.  Upon arrival of my 4 gorton #2s I put 2 on each end of main where original non working ones were w 1/2" pipe, tap is 1/2" as well.  My real question is I now make no pressure, and no vapor pressure at all, I get the needles bouncing a little but they make the first tic mark in the slight bounce if that.  I have checked numerous times thru the heat cycle and have not found them to read anything.  I removed both new guages(vapor and 3psi max) and cleaned them and blew on them and they do read and work it seems.  Is this a problem, maybe too much venting?  should I put only 1 gorton on each tap and see if I build a little pressure or is this ok?  thanks for your advice

BobC

How is the system performing?

Does the building heat ok? Do the new Gortons close when they get steam?



If your boiler and the radiation is well matched you might well not develop any real pressure unless you were coming off a deep setback or it was extremely cold out.



Bob

jimmythegreek

thanks

the building heated ok before, but I had some rads that got nothing.  I spent the past 2 weeks changing valves, repitching rads, even slightly jacking up a long branch off a main that sagged w building settling and got all 3 floors above working in one fell swoop, im happy.  I actually feel like I have better heat now, but I also just renovated the exterior last 3 months, and blew in cellulose, foam boarded the sheathing, tyvek wrapped w tape, and new windows(new contruction style) and building is super tight now so comparing to last year much better.  weird thing was previous to the 4 gortons I was making pressure on both guages, thats whats buggin me.  And yes I think the vents are closed, after a decent setback I hear or see nothing, I have yet to hear them hiss or puff steam since install. 

Rod

New Main Vents

Hi- It maybe that before the steam was backing up as the air couldn't get out and therefore was blocking the steam. Now the steam is getting to the radiators where it is condensing and doing its job. The added condensing is now using the steam which previously just backed up. You can test the vents with a strip of paper. Hold it near the vent when boiler turns on and when the paper stop fluttering you know the vent has closed and is working. Some vents make an audible "clunk" but if near the boiler sometimes this is hard to hear. I agree with Bob. It's almost impossible to over vent on the mains.

- Rod

BobC

Never have too much main venting

If the old vents were not working or much too small you may have just been seeing the back pressure from the air in the system. You pretty much have to have your war right next to the Gortons to hear them work, the only way I can tell my #1's working is to hold my hand up and feel the air coming out - be careful because the steam coming out just before it closes will burn you. You cannot over vent steam mains.



As long as the building is heating ok just sit back and count the fuel savings from all the work you've done.



Bob

The Steam Whisperer (Formerly Boilerpro)

Cleaning....

Along with the vents you said you cleaned up the boiler.  I put  a boiler in a two flat about 6 years ago for an engineer.  He kept very close tabs on the boiler.  What he found out was that if the boiler started building more pressure on a heating cycle, the boiler needed to be cleaned.  I haven't quite figured out how this works, but it may explain your situation, along with the previous vents being much too small.

Charlie from wmass

Check for white smoke

All that cleaning may have opened up a rust shut hole. Also the vents working will give more room for the steam to fill and as said it will give more area for condensing.

haaljo

I upgraded all my vents installing 3 #2's and 4 #1's on mains

Installed a 3# gauge and had boiler cleaned and tuned up at same time among other things. Had same symptons so I removed all the main vents and put in plugs. There was no difference in pressure.

So give that a try and see if you get pressure. For me it wasn't the vents but rather the firing rate had been set too low. I think it was .75 therms/hours. It was raised to about a therm/hour and pressure has been fine since then.

It's good that you can pinpoint the problem to just after you put in the main vents. Unlike some of us that make a whole bunch of changes and then try to figure out which change caused the problem :-)