moisture in the pneumatics

[mapleman]

So I have been lucky enough to come into a school system that has been neglected for many many years.... Inow have lots of old systems, steam mostly, all run by pneumatics to each classroom. I get a call that there is water dripping out of the thermostat. when I first started the job a month ago, found schools that the air compressors were full of condensation, air dryers unplugged, seperators full..... So whats my best method to get these air lines dried out? I have the compressor empty, air dryer running ect. will the moisture work it's way out in some areas? or do I have a multitude of problems ahead?

when I pulled the tstat, it did clear up at that point.

[lwarren]

When I was still in service I delt with this a number of times. I would go get some large bottles of dry nitrogen and a regulator and tee the nitrogen tank regulator into the main air line past the dryer. Shut off the main air and adjust the nitrogen regulator to deliver the desired control psi to the system.

Depending on how big the pnuematic system is you may get by with two nitrogen tanks or it may take way more. Just make sure when you do get it dry that the dryer is working and has the correct capacity for the system.

[orion242]

Before you even start that I would open up the mains at every control panel one at a time and let them bleed until it's mainly air. That should get the bulk of it out. Then after your all set with whatever measures you decide to do, install filters in all the control panels. The filters that change color when wet are a good idea.


Water coming out of the stats is bad news.

>will the moisture work it's way out in some areas?

Not unless you give it a good reason to move out of all the low spots.

>or do I have a multitude of problems ahead?

Very likely.

[beer30]

Back in the day (I think it was a Wednesday) we would run R11 through the air lines. Dried the lines out real nice. I would not recommend you do this now. This was years and years ago.

I have had success making a low spot in long horizontal runs, tee in a drain valve and blow er down every hour/day/week until the system seems dry. After that, you will likely have many t-stats, receiver controllers and transmitters to replace.

A better solution is a DDC retrofit.

[joey791]

Before you even start that I would open up the mains at every control panel one at a time and let them bleed until it's mainly air. That should get the bulk of it out. Then after your all set with whatever measures you decide to do, install filters in all the control panels. The filters that change color when wet are a good idea.


Water coming out of the stats is bad news.

>will the moisture work it's way out in some areas?

Not unless you give it a good reason to move out of all the low spots.

>or do I have a multitude of problems ahead?

Very likely.

Agreed, I was would like to add if you have any known "low points" in the tubing run outs, cut the tubing and drain from there also.

[simux]

Besides a working air dryer, I recommend a good oil removal and pressure reducing station. The ones that I really liked were the Johnson Controls A-4000 series. It has a coalescing filter, an activated carbon oil removal filter, and condensate filter. Then I would install an automatic tank drain to keep water out of the system.

[mapleman]

Some great Ideas guys thanks.. now to get the Municipality to ok the work... because of the economy our mayor has put a freeze on spending... what he doesnt realize that the "freeze" may FREEZE the schools if all the nessesary things are not done to the systems such as regularly bleeding the water from the bottom of an air comressor and money put into air dryers that will work!

[D'Laine]

I came across this one night and the building was starting to freeze solid. Didn't go home that night!

The other bad news is that oil tends to get pumped out with the compressor air and if it's made it's way down the pneumatic lines, then you'll have oil and water coming through as well. It will soften and rot out gaskets and o-rings in controls and they'll fail, in time. Be prepared for expensive repairs in the future.

D.

[twisted pair]

I would agree with everything already said. If it is really bad, you might consider a product called Pneu-Flush made by Nu-Calgon. It is very $$$$, but does a better job than nitrogen. Nitrogen is good for moisture contamination and reasonable inexpensive, however if you have oil or a combination of moisture and oil, I would spend the extra money, start with nitrogen and then do a flush using the specialty compound.