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alphapointe
Don't Touch Me
Premium,MVM
join:2002-02-10
Columbia, MO
kudos:2
Reviews:
·Socket Internet ..

Compressed air dryer ready to make me scream.

I've been working on the pneumatic thermostat system in my apartment building yesterday and today.

We put in a new dryer yesterday (the old one was about six million years old). We leak and pressure tested it and put it in service about 4 PM. At 0800 this morning, we checked on it, and the compressor was tripped out on thermal overload and air pressure was zero. We reset the compressor and let it build pressure back up and it fell off rapidly. After bypassing the dryer, the pressure stopped dropping.

We found a leak in the threaded fitting on top of the dryer, and I fixed it, leak tested it with soap, and it was fine. At 8PM tonight, the desk attendant called me and advised me that the air pressure was dropping off. I went down, shut down and bypassed the dryer, and everything returned to normal. I have not leaktested it yet, as I'm pissed and confused.

What is going on here? It was fine for almost 10 hours, then it starts dropping again? What the hell am I doing wrong here?

I will probably have to call the HVAC guy back, but that's expensive...
--
"When the hammer drops, the bullshit stops"


garys_2k
Premium
join:2004-05-07
Farmington, MI
Reviews:
·Callcentric
·callwithus

If "we" put in the dryer then "we" should be able to find the leaks.

Do the usual, soapy water on all the fittings and check regularly.

Is this a refrigerated dryer or does it use a regenerating desiccant? If it's the regenerating type, is it stuck "blowing down" one of the chambers?



alphapointe
Don't Touch Me
Premium,MVM
join:2002-02-10
Columbia, MO
kudos:2
Reviews:
·Socket Internet ..

Management bought this thing:
»www.harborfreight.com/compressed···211.html

Reading the reviews, it looks like the drain line is a problem... something to check on.
--
"When the hammer drops, the bullshit stops"



54067323

join:2012-09-25
Tuscaloosa, AL

said by alphapointe:

Management bought this thing:
»www.harborfreight.com/compressed···211.html

Reading the reviews, it looks like the drain line is a problem... something to check on.

Beware Harbor Freight Tools = extremely cheap junk.


alphapointe
Don't Touch Me
Premium,MVM
join:2002-02-10
Columbia, MO
kudos:2

Don't I know it... management around here can't understand the concept of buying good stuff for a bit more money vs. buying cheap junk and replacing it all the time...
--
"When the hammer drops, the bullshit stops"


TheMG
Premium
join:2007-09-04
Canada
kudos:2
Reviews:
·NorthWest Tel
reply to alphapointe

Most air dryers I've seen use either a float valve or an electronically timed solenoid valve to dump the accumulated water when required.

Perhaps the dump valve in your air dryer is not functioning correctly and is staying open causing the loss of pressure.

Any leak that you need soap to find, is not going to cause enough loss to cause any problems, unless the compressor is seriously underrated for the task. The leak is most likely quite significant, which is what leads me to believe it's the dump valve.



alphapointe
Don't Touch Me
Premium,MVM
join:2002-02-10
Columbia, MO
kudos:2
Reviews:
·Socket Internet ..
reply to alphapointe

I think I found the problem(s):
1: The air compressor is seriously underrated for the job. It's a little 10gal portable one that (IMO) sucks for the job. I'm recommending that get replaced.

2: I found the joint on the output of the dryer leaking (it was fine yesterday), and when I took the fitting apart, the thread compound was nearly gone and I found oil in the threads. I'm guessing the POS compressor is spitting oil into the lines which is eating the thread compound, causing a leak, and since the compressor is way too small, throwing the whole thing out of whack.

I can't find any problems with the dump valve, it opens and closes like it's supposed to, so I don't think it's a factor.

My ideas for fixing this come Tuesday are: replace the compressor with a bigger one, and putting a coalescing filter between the output of the compressor and the input of the air dryer to catch any oil before it gets into the dryer.

Thoughts?
--
"When the hammer drops, the bullshit stops"



alphapointe
Don't Touch Me
Premium,MVM
join:2002-02-10
Columbia, MO
kudos:2
Reviews:
·Socket Internet ..
reply to alphapointe

Still leaking from somewhere... I loaded it to 80psi and closed the isolation valves at 5:30, and at 7:45 it was down to 0...

I'll take another shot with the soap on Monday...

Dryer and compressor:




Post-dryer filter and a couple of old, busted gauges:



Air out to main and east wings:


--
"When the hammer drops, the bullshit stops"


Raphion

join:2000-10-14
Samsara

1 recommendation

With so many joints, regulators, valves, and "old busted gauges", you certainly aren't short on leak candidates....



alphapointe
Don't Touch Me
Premium,MVM
join:2002-02-10
Columbia, MO
kudos:2

You got that right...

Doug asked me yesterday what my thoughts were to fix this, and I said plastic explosives would be a good start...
--
"When the hammer drops, the bullshit stops"


garys_2k
Premium
join:2004-05-07
Farmington, MI
Reviews:
·Callcentric
·callwithus
reply to alphapointe

Click for full size
I looked online to see which port was inlet v. outlet (inlet's on the left if you're looking at the front of the dryer) and I found their wiring diagram. Amazing how the Chinese could so screw up a color scheme...

Makes me want to scream, too.

As for the leak, maybe the compressor's the culprit. Assuming you've closed that isolation valve and that's not it, I'd also look hard at those fittings mounted on the wall.


alphapointe
Don't Touch Me
Premium,MVM
join:2002-02-10
Columbia, MO
kudos:2
Reviews:
·Socket Internet ..

There was a long conversation on Thursday when we were installing this concerning "what moron makes green a hot wire?"

Isolation / bypass valves are closed, and the pressure still bled off. I have ordered replacement gauges, as I'm not sure they're not leaking. Both leaks that I have found were between the copper lines and the shitty steel threaded inlet and outlet ports on the dryer... I winder if the different metals have something to do with that? (I've never had to deal with this before)
--
"When the hammer drops, the bullshit stops"



Lurch77
Premium
join:2001-11-22
Oconto, WI
kudos:4
reply to alphapointe

If there is one thing I have learned about pneumatic HVAC components in my relatively short career, it's don't go cheap. If there is anyway to get management to do this right, get rid of the harbor freight compressor and dryer. Harbor freight is great for some things. Building controls is not one of them.



alphapointe
Don't Touch Me
Premium,MVM
join:2002-02-10
Columbia, MO
kudos:2
Reviews:
·Socket Internet ..

I'd love to replace it with an Ingersoll Rand, but knowing Mark, we'll end up with a bigger belt-driven HF compressor...

I was thinking, is the dryer really necessary? I've never had issues with water in the lines before...
--
"When the hammer drops, the bullshit stops"



Lurch77
Premium
join:2001-11-22
Oconto, WI
kudos:4

1 recommendation

You do want to dry the air. Any moisture that gets out to the controls would be a bigger headache than what you're dealing with now.


TheMG
Premium
join:2007-09-04
Canada
kudos:2
Reviews:
·NorthWest Tel
reply to alphapointe

WTF!

That's one seriously hacked setup. It's like someone went shopping and picked up whatever they could get the best price on, with no regards to the specifications/ratings and quality.

That portable compressor does not belong in a pneumatic HVAC system. Ideally you want a low speed 100% duty cycle rated belt driven compressor. Pneumatic systems are prone to leakage as they wear and age. You don't want a small leak in one part of the building to cause your compressor to trip out, taking out the HVAC in the whole building!

A properly spec'd, good quality compressor will also pay for itself eventually (if properly maintained). We have systems with DeVilbiss air compressors that have been going strong for nearly 30 years now.

said by Lurch77:

You do want to dry the air. Any moisture that gets out to the controls would be a bigger headache than what you're dealing with now.

I concur. Once water gets into the systems, things will eventually begin to behave erratically. The pneumatic thermostats, valves, etc, are designed to work with air, not water!


pende_tim
Premium
join:2004-01-04
Andover, NJ
kudos:1
Reviews:
·Comcast
reply to alphapointe

Most installs I have seen that make instrument quality air, have a filter/regulator to remove the heavy impurities BEFORE the final high quality dryer.

I don't understand why there is a canister dryer shown in the pictures after the new dryer???? If the new dryer was doing it's job, this is not needed. Could this filter be mis-located and should actually be between the compressor and the new dryer you just installed?
--
The difference between genius and stupidity is that genius has its limits.


shezams
My Other Car Is A Zamboni
Premium
join:2001-08-14
Hyattsville, MD

I work for a large University and I work in Controls. If you have an option you might consider going electronic. Pneumatic can work but it needs to be properly maintained and by someone who really understands pneumatic controls. I don't get the feeling you have someone who really can take care of the pneumatics.
--
Simple rules - no offsides, no intent to maim, everything else is all good!



alphapointe
Don't Touch Me
Premium,MVM
join:2002-02-10
Columbia, MO
kudos:2
Reviews:
·Socket Internet ..

1 edit
reply to alphapointe

The cylinder dryer is installed in the wrong place. That will be moved tomorrow (I wasn't in there when the guy from Air Systems did the piping work, or I would have caught it...)

As for replacing controls with electronic instead of pneumatic... good luck with that. This building is 50 years old, and most of this crap is as old as the building. I have to beat on Mark to spend $1000 on a decent compressor, let alone spending north of half a mil to replace all of this shit... (you should see the chiller, it looks like something out of a nightmare!) At least we got new boilers... the old one was terrifying. The old one was replaced with 5 Munchkins and they don't scare me like the old one did...

Our HVAC guy from Air Systems is pretty good at keeping everything working, but he's been sick lately, and his judgement seems off. Our other two maintenance techs don't know anything about this, and I'm not an expert...
--
"When the hammer drops, the bullshit stops"



alphapointe
Don't Touch Me
Premium,MVM
join:2002-02-10
Columbia, MO
kudos:2
Reviews:
·Socket Internet ..
reply to alphapointe

Click for full size
Current Setup
Click for full size
Proposed Setup
Visio drawings (I can't draw...)

patcat88

join:2002-04-05
Jamaica, NY
kudos:1
reply to alphapointe

»www.dewalt.com/tools/compressors···146.aspx this is one of the most powerful 15 amp plug air compressors around. Belt driven, with universal (brushed) motor. Its unique compared to all the other induction motor compressors.



alphapointe
Don't Touch Me
Premium,MVM
join:2002-02-10
Columbia, MO
kudos:2
Reviews:
·Socket Internet ..

1 recommendation

reply to alphapointe

Problems located and solved.

1: The pressure was dropping through the air dryer because it was freezing up. I put a temperature logger in the mechanical room, and it was getting to about 45 in there... Hot gas bypass valve was readjusted per HF, and I'm shutting the dryer off if it gets really cold. I'll probably put it on a thermostat to keep it off if it's too cold.

2: The old gauges and filter have been replaced.

3: A second oil separation filter was added between the compressor and the dryer.

4: We have a new compressor now... it's not the Ingersol that I wanted, it's a Kobalt, but it's better than that little bitty HF portable one...

5: I put an automatic condensate drain valve on the compressor, as the night clerks were not draining the condensate off each night like they were supposed to...

Thanks for the suggestions and tips, it gave me a place to start looking, and (not insignificantly) helped me convince management to get a better compressor. (Now if I could convince them to lose the pneumatics all together... nice wish!)
--
"When the hammer drops, the bullshit stops"


EDIT: Spelling


TheMG
Premium
join:2007-09-04
Canada
kudos:2
Reviews:
·NorthWest Tel

said by alphapointe:

1: The pressure was dropping through the air dryer because it was freezing up. I put a temperature logger in the mechanical room, and it was getting to about 45 in there...

So the mechanical room is unconditioned space?

They should put a heater in there, or crank up the heat if it's already heated.

Obviously, since the air dryer functions by condensing moisture from the compressed air, it wont work if that air is already very cold.

Oh, and that's kind of a crappy air dryer for it to freeze like that. A good one should have a thermostat to provide better temperature regulation and prevent freezing.

Although, you are operating it probably well below its intended ambient temperature range.