How to drain these lines to A/C unit?


  #1  
Old 06-10-18, 12:14 PM
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How to drain these lines to A/C unit?

Sometimes the AC in here stops cooling. The easiest, and most common fix, is to drain lines that run to/from it until the water is clear again. I've watched a maintenance man do it and I'd like to try. Here is the AC unit (two photos):

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In the second photo, I've circled the nozzle that you have to loosen:

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Here's a close up of the nozzle. He appeared to unscrew this thing counterclockwise with pliers of some sort. What tool do you recommend and where should I unscrew (e.g., on the nut or on the part that protrudes from it)? Also, what kind of tool do you recommend?

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Once the nozzle was loosened, he pulled these two levers to drain the lines. Water came out of the nozzle. He did it until the murky water that came out was clear. He started with the blue one in front. I don't remember in what direction he turned the lever or how much pressure he applied. It didn't seem to be a lot.

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Here's a close-up of the blue lever in the front. It controlled one hose. Again, he did this one first:

https://photos.app.goo.gl/S8K73YBzRbrx57CA7

Here's a close-up of the red lever in the back. This controlled a separate line. Again, he did this one second:

https://photos.app.goo.gl/TGL5jLLqtB58DhyS6

He did not unscrew anything around the levers. That is, after the nozzle displayed above was opened, he just turned the levers to drain the pipes.

I think I've described the procedure pretty well. Could you read what I've said and add any additional information you think I need to know before trying this myself? I have permission to from the owner.

Thanks!!!
 

Last edited by PJmax; 06-10-18 at 12:55 PM. Reason: added some pics from links
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Old 06-10-18, 12:55 PM
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Those are not drain lines, The drain lines are the white PVC pipes. Those things you are messing with are the cold water supply lines from a building chiller.

It sounds like the chilled water supply is getting air bound. That should be handled by a tech.
 
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Old 06-10-18, 01:24 PM
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I don't know what they are. I live in a high-rise building. There is some kind of a problem in the building in which debris is building up in the AC pipes that run from the ceiling all the way down. Evidently, that debris is getting into people's AC units and is stopping them from cooling. The procedure I described is exactly what the maintenance man (who is not an AC tech) did to clear the debris and make it work again.

With this clarification, could you help me now? Thanks.
 

Last edited by TonySexton; 06-10-18 at 02:15 PM.
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Old 06-10-18, 01:51 PM
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did not clear the debris.
If he did it and it didn't help...why are you wanting to?

I'll put it right out there, Pete was being nice. You do not want to be messing with this. Do it even slightly wrong and you could be in for thousands of dollars in repairs...yes, thousands.

If this is affecting the whole building, then they need to either purge and flush the entire system affected or at least install some sort of sediment filters which could be easily bypassed, cleaned and reinstalled.

I ran a building with 100+ rooms with individual coils fed from a central chiller. Every spring my guys would have to go to almost every coil, disconnect lines, blow and vacuum them out, then reconnect and air purge each unit. We tried and tried to get the owners to install filters of some sort...but they figured using our manpower was the cheaper route.

Others may feel differently and offer to help, but I sure recommend against this unless POSSIBLY you have a maintenance man show you the exact procedure.
 
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Old 06-10-18, 02:16 PM
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It DID clear the debris and make it cool again. It was a typo.
 
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Old 06-10-18, 02:19 PM
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Do you guys feel this way because you haven't done it before? Again, I described exactly what he did. All he did was to: (1) turn the unit off; (2) unscrew the nozzle; and (3) pull down on the levers to make water come out of the nozzle. He stopped pulling down on the levers when the water that came out was clear. My main two questions are: (1) how to loosen the nozzle. That is, where exactly do I turn (e.g., the nut or the cube that protrudes past the nut). The second question is: What direction do I pull the levers? Thanks again!!!
 
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Old 06-10-18, 05:03 PM
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I have done it. I'm still not going to recommend that a home owner does this.

My company has a 10 million dollar insurance policy in case it creates an expensive mess.

Since the pipes are not insulated it is more likely that you have a water source heat pump than a chill water air handler but the procedure is the same.

I went behind another AC company that did 2 million dollars worth of damage while trying to work on a chill water air handler in the past.

More recently I went behind another company that did $75,000 worth of damage.
 
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Old 06-10-18, 07:33 PM
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Fair enough, Houston204, but did you read what I said about what the maintenance man did? It looked simple. I watched the whole thing. Could you just tell me if it is as simple as: (1) loosening the nozzle; (2) draining water from the hose with the blue handle until it's clear; and (3) draining water from the hose with the red handle until it's clear? That's all I saw done. In fact, I think the water in one of the hoses was already clear. Also, if this is right, where do you turn the nozzle to loosen it and by how much do you loosen it? Also, in what direction do you pull the levers? Thanks.
 
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Old 06-10-18, 10:00 PM
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Those are just regular ball valves. Turn them 1/4 turn up to close them.

I would also try to flush out the unit heat exchanger.

That blue handle Nibco ball valve is a good product that I trust.
It probably says 400psi cw on the side of the valve.

That red handle valve probably doesn't say 400 psi on the side.

The pressure in those pipes is related to the amount of floors above you.

The 34 story building that I work in most has 12 psi on the top floor and 266 psi at the chiller in the basement.

Yes, it is easy to flush the unit but accidents happen.
1/4 turn valves act fully open until the last bit of the valve is off.

Introducing Air in the pipes can cause high pressure lockout for you or your neighbors.
 
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Old 06-10-18, 11:06 PM
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The item circled orange looks like a check valve.

I would try to flush it before trying to take it apart.

I have only seen them require cleaning when installed above a sump pump.

It is common to see a check valve by a water source heat pump.
 
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Old 06-11-18, 05:31 AM
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Hi

The device the technician cleaned is a strainer. It simply has a screen in it that can be flushed. Procedure is to shut both ball valves( perpendicular to pipe ) Take out the square plug after putting a bucket under it. There will be some pressure at first so loosen and wiggle plug before you take it all the way out. Once it is out you will open one of the ball valves ( parallel to the pipe ) and catch the stuff in a bucket. You want to back flush the opposite direction of normal flow. Should be an arrow on strainer indicating direction of normal flow. Once it is flushed, put plug back in with some thread dope or teflon tape and open both valves again. Whether it is a water source heat pump or chilled water coil, this will work. The bigger question is how is so much stuff getting in the lines to plug the strainer so often? Is pipe deteriorating? Should be looked at by a pro.
 
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Old 06-11-18, 11:09 PM
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Jeffrey:

Thanks. Two questions:

(1) To take out the square plug, do you turn the plug itself or the nut above it? Also, are you sure you need to take it all the way out? I don't recall the maintenance man having done that.

(2) I don't understand the part about "you want to flush the opposite direction of normal flow. Should be an arrow on strainer indicating direction of normal flow." First, I don't know what the strainer is. Is there one pictured here? Second, what is back flushing the opposite direction of the normal flow? If I recall correctly, the maintenance man simply turned the ball valve (the lever) to make water come out of the plug. Once the water was clear, he stopped. I don't recall him doing anything in terms of "opposite direction of normal flow"? Thus, could you please explain what this means in greater detail? Thanks.
 
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Old 06-12-18, 04:39 AM
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The item circled orange is your Y strainer. It looked like a check valve but it could very well be a strainer. There are a ton of utube videos showing the cleaning procedure.

Just shut off both valves, unscrew the cap, remove and clean the filter in the strainer. It looks like a brass cup with no bottom made of a window screen.

If you shut off the suppy water and open the return water valve it will back flush the heat pump. This will help remove trash from the heat exchanger.

Be careful. The potential water damage can far exceed the cost of a service call.
If that cap has 50 psi behind it, it can put out an eye if you don't release pressure after shutting off the valves.
 
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Old 06-12-18, 05:45 PM
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Thanks. Can you find a video on how to do the exact procedure I've described above and post the link here? I didn't have any luck.
 
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Old 06-12-18, 06:30 PM
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A do-over of sorts

Is there any way we could sort of start this thread over. What I witnessed was a basic procedure. It seems like, for one reason or another, it has been overcomplicated. Perhaps I have not been as clear as I ought to have been.

1. The first step, presumably, is to turn these levers to close valves. What direction do I turn them in?

https://photos.app.goo.gl/ed2A5yzgRnazMihS8

2. The second step, presumably, is to loosen the nozzle, or cap, as another poster put it. But, again, I don't know which part to unscrew. Is it the nozzle/cap or the nut under it? Please see photo.

https://photos.app.goo.gl/2C8x4TCN2vUgZtVEA

3. The third step is to turn the levers to flush the unit. The maintenance man did the blue lever pictured above first and the red lever (the one in the back) second. As far as turning it, he seemed to just turn it down kind of fast, which made water come out of the nozzle/cap, which he collected in a jug. Correct me if I'm missing something here.

4. The fourth step, presumably, is to screw the nozzle/cap back on. Correct me here if I'm wrong.

5. The fifth step, presumably, is to turn the levers back to the position that they were originally in, and which is illustrated in the first picture above. Again, correct me if I'm wrong.

These are the only steps I recall the maintenance man having done. Please let me know if these directions are correct.

Again, it would be helpful if you could post a video of someone doing this procedure.

Thank you again for your consideration.
 
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Old 06-14-18, 09:43 PM
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I could REALLY use your help here, guys. The AC is out again and its hot outside.
 
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Old 06-15-18, 01:21 AM
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Ok, I said I wouldn't, but you are determined and its your money at stake, so...

The levers will only turn one way and they have a built in stop to limit how far they can be turned...thats why they are called 1/4 turn valves! In line with the pipe and hose means they are open. When they are 90 degrees to the pipe/hose...they are closed. You can open and close them to your hearts content while the system is sealed, so you can see exactly which way they move.

Can you not see the obvious tool marks on the plug in the center of the cap? The larger portion behind it would be if you actually needed to replace the internal strainer or the plug was completely blocked. Use an adjustable wrench or box wrench and make sure it fits tightly. It will take a bit of force to break it free, do not stress the pipe or any connections. Hold them steady. Ideally you would use a wrench on the large flats of the cap to hold it as you remove the plug from the center.

Perform the procedure as you describe/remember it. It appears there is teflon tape or paste on the plug threads to help it seal...you need to replace that after you take it out. Any corner hardware store should have it.

I hope it goes well, but if it doesn't...well, you were warned.
 
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Old 06-15-18, 01:55 AM
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AFTER closing the valves (handles perpendicular to the piping) remove the outer cap of the Y-strainer and remove the internal screen. Clean the screen thoroughly using an old toothbrush and running water, removing ALL the crap and corruption. Reinsert the screen and replace the cap making sure the gasket on the cap has not been lost or damaged. A SMALL amount of non-hardening thread sealant (Teflon past) may be used on the threads and gasket. Once the cap is tight re-open the valves.

Any statements that the screen can be cleaned by removing the pipe plug in the center of the cap are mostly wishful thinking. While it is SOMETIMES true that the screen can be partially cleaned in this manner the truth that I discovered was that unless the screen was removed and scrubbed it would soon plug up again. I worked in the field for over thirty years and found that MOST Y-strainers that had plugged screens would not clear by simply blowing through the body and out the (drain/blow out) plug.
 
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Old 06-15-18, 04:21 AM
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Thanks guys, but I can't figure it out. It would be great if I could get clearer instructions on (1) where EXACTLY to position the wrench and (2) which direction to turn in. Diagrams would be helpful. No, I don't see obvious tool marks and, quite honestly, I'm not even fully clear on what the "plug" is. I'm presuming that that's the cubical brass thing that projects out and that I've circled above. That is the thing that I am turning COUNTER-CLOCKWISE. But it won't budge, and I don't want to use any more force.

Really drowning here, guys. Need SALVATION.
 

Last edited by TonySexton; 06-15-18 at 04:59 AM.
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Old 06-15-18, 12:03 PM
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The square plug in the center of the cap? You can't see that? Or obvious tool marks where the brass is scratched up some? Then the flats on the cap below the plug, where you would use a wrench to remove the entire cap and clean the strainer?

As Furd said...the strainer should be removed and cleaned as that's why it's probably happening over and over. Obviously the maintenance guy knows absolutely nothing, as most of them don't. He'd rather just keep doing over and over what the guy before him taught him, because they're lazy or just stupid or both.

You are turning the correct way...CCW loosens, CW tightens (in most cases!). Sometimes it needs a sharp rap to break it loose, then it will spin right out. Sometimes old corroded fittings require more force or heat. That is neither old or corroded.

I seriously don't know WHY you are dead set on doing this yourself. You obviously have very limited knowledge in this area (that's not a slam...just a fact) and you are gambling that everything will go smoothly. Spending $200 or so for 15 min of someones time who KNOWS what they are doing would seem to be money well spent to me. Ideally it would be a plumber or tech who works for a company that has proper tools, insurance, and such. Not knowing your actual location since your IP is all over the place...$200 may be low...I dunno. Far cheaper than finding a new place to live or paying for thousands in repairs though.
 
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Old 06-15-18, 02:28 PM
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Thanks. I had to call the maintenance man. I wanted to do it myself because I don't like having to deal with the maintenance man every month--it's a hassle. Also, there is usually at least one day a month when I don't have AC because I have to wait on him to show up.

Could you please take on of my images and identify: (1) the square plug in the center of the cap with the obvious tool marks?; and (2) the flats on the cap below the plug; and (3) the cap.

I simply can't be sure what you referring to. I'm not being a wise guy either. I'm telling you straight up that I need an image to be sure. I might have to do this one day, including to clean the strainer.
 
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Old 06-15-18, 04:39 PM
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OK. I just watched him do it. He unscrewed the nut this time and cleaned the strainer. But he also showed me that you can unscrew the cubical brass piece to get it to open up. He had an adjustable wrench that clamped down by pressing a lever at the bottom of it. He was also willing to use more force than I was. Do you have any wrench recommendations? Thanks.
 
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Old 06-15-18, 05:12 PM
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The "plug" is the square-headed part that you circled in orange. Note the white paste or tape at the bottom of the square head, that is Teflon paste or tape. It is to prevent leakage, and in my opinion the paste is better than the tape although messier. Many semi-skilled "maintenance" people think that the strainer can be cleaned by removing the plug and then opening the upstream valve to blow water through the center of the screen, even to the point of sometimes installing a valve in place of the plug. Only rarely does this REALLY clean the screen, it merely blows a small amount of the obstruction material (dirt) away from the screen allowing a small amount of area for the fluid to go through the screen. While this is often enough to get temporary flow it will NOT last long if the circulating water has a high amount of crap in it, which yours may very well have.

The "cap" is the hexagon part that you have circled in blue and if you look closely you will see that the hexagon continues out to the outer edge of the circular piece and that there is a seam between this flat area and the body of the strainer. This is where the strainer comes apart to remove the screen which is cylindrical and fits into the body of the strainer about an inch or two, depending on the size of the strainer.

Note well that the cap will most likely be very tight and that you really need to have a close-fitting wrench on the hexagon portion while also using a second wrench to restrain the body of the strainer from moving. If you do not use the "back-up" wrench you could possibly break something and then you would be in a world of hurt. Sometimes the only way to get the cap loose is to have a helper smartly rap on the end of the wrench on the hexagon portion while you hold the body from turning with the back-up wrench. I've seen them that took several raps on the end of a foot-long wrench.

I have to agree with Vic (Gunguy) that this is probably not a DIY job for someone that has no experience working with piping systems.
 
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Old 06-15-18, 08:42 PM
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Very helpful. Thanks. I agree. MUCH care has to be taken to avoid breaking those pipes. I don't know if I am every going to do this on my own. But now at least I know what to do in case of emergency.
 
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Old 06-15-18, 11:24 PM
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Do you have any wrench recommendations?
I would probably use my 12 inch aluminum Rigid pipe wrench for the backup wrench and use my rigid spud wrench for the hex nut on that strainer.

It sounds like your building needs a bypass filter in the water loop.

I take care of a house in River Oaks that has a 30 ton chiller on the main house. The strainer by the chiller would regularly become restricted until we added a bypass filter.
 
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Old 06-16-18, 07:35 AM
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Where the does the bypass filter go, exactly? Remember, this is a 30-story high-rise with over 400 units.
 
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Old 06-16-18, 08:11 AM
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It is in one of the basement floors with the 34 story building that I work in most .

We added one on the basement of the house with a chiller that service .

This is not something to add at your end. The building engineering needs to have it installed near their equipment.
 
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Old 08-08-18, 06:54 PM
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Update. Still Need Guidance

Okay. Just went out again after tech had cleaned the filter.

Needed AC ASAP due to summer heat. Did easiest repair where you unscrew the plug, open the valves a little, and let the water come out.

But I didn't know how much water to let out. I probably ended up draining about half of a large bucket's worth. It was about the some amount from each line. The started to come out pretty clear after several squirts, but not pristine or anything. This leads to first question:

1. How much water should I let out?

AC wasn't working very well, if at all, after I did this. So I turned it off and opened it. This is what I saw:

https://photos.app.goo.gl/44kE5URsqkmNvAqR8

I poured some water in this tray:

https://photos.app.goo.gl/UoVWtfmLgNjnYGwaA

The idea was to see how fast it would drain. The maintenance man had told me previously that, if it's not draining fast, there could be a clogged line on the inside.

Didn't drain that fast. I couldn't even tell where the drain was. This leads to second question. Was this the drain in the tray (it was at the back near the wall)?:

https://photos.app.goo.gl/SmhYtM5DfTX4sGiK7

This is the end of the tray closest to the front of the AC. I didn't see a drain here:

https://photos.app.goo.gl/hqJAtkhmrz4dRpn86

Either way, my last question is:

3. Why hasn't the compressor kicked on yet? I left the AC running. It eventually cooled from 78 degrees to 72, but it took 45 minutes to get there. Does the fact that it took so long, coupled with the fact that the compressor has not kicked on yet, mean that:

(a) A tube on the inside is clogged?
(b) The filter should have been cleaned (note that I could not get the nut off because I don't have the right wrench)? and/or
(c) I let too much water out of the lines.

Please, any guidance would be helpful. You guys have helped me get this far.
 
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Old 08-08-18, 07:08 PM
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I don't understand. Is this a "tech" you are paying or a house tech ?
If he just repaired it..... call him back.

We can't see the drain in your condensate tray. Which way does the water flow ?
It should be pitched so the water runs toward the drain.

There is a sensor with yellow wire that sits over the tray. If it senses water the compressor won't start.
 
  #30  
Old 08-08-18, 07:50 PM
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Maintenance man.

The water appears to flow toward the back. I can't be certain though.

The compressor is kicking on some now. The basic repair that I did actually worked!!! (At least for the time being as we know).

Still need to know how much water to drain out. Or if it even matters. I just don't want to damage AC by draining too much water.
 
 

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