Can someone help me figure out how to bleed/purge my baseboard heating system?

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Old 01-21-18, 12:18 PM
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Question Can someone help me figure out how to bleed/purge my baseboard heating system?

Just moved into a house with noisy, gurgly baseboard heating. After some research, I've found that this noise can be caused by air in the baseboard piping, and by the system needing to be purged of that air. I've been trying to figure out how to do this via youtube tutorials, but I think there's something I'm missing.

For reference, here's the video that I've been following.

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A. This is where the shut-off valve for the loop is. It's also where the hose attaches.

B. This seems to be the fill valve.

C. Two water supply valves? I don't totally understand why there seems to be two shutoff valves in a row along the same pipe. Both have caps on them near the base of the handle. I'm not sure why. Here's a close-up picture of what they look like.

The video references zone valves (at 1:07) but as far as I can tell, there are none on my set-up and it is only single-zone. I assumed this meant I could skip the step where he switches the zone valves to manual.

At 1:21-1:39 in the video, he opens the valve that has the hose attached. He says that this will allow the fill valve (B on my setup) to fill the piping with water and eventually eliminate air bubbles. For whatever reason, when I first approached my fill valve, the position of both of the water supply valves at (C) was "off," so turning the valve at (A) just resulted in the water already in the pipe leaving without being replaced. I turned on the two water supply valves at (C) to try and get water back in the system.

From there, I've encountered conflicting information regarding how to handle this. I was told by someone that I should try to increase the supply on the two "C" valves until the pressure on the system is above operating level, and then slowly decrease/toggle the the supply of water until the non-operating pressure is at 12.

I've also read that the fill valve (C) is supposed to handle the pressurization on its own. On my setup, it doesn't.

Any ideas? The HVAC guys in my neighborhood have all been super busy this winter, so the wait-times on calling for help are typically a half-month or more. It would be great to be able to resolve this on my own.

P.S. There are no bleeder valves along the baseboard pipes themselves.
 

Last edited by PJmax; 01-21-18 at 12:28 PM. Reason: added pic from link
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Old 01-21-18, 12:30 PM
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Welcome to the forums.

We need a side picture of the B area. That's your air bleed system.
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Old 01-21-18, 12:42 PM
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Old 01-21-18, 01:15 PM
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The pics are a little distorted.

Is the valve marked A a shut off and drain or just a drain.

Could you post better pics of your supply piping and your feed valve.

All this bleeding is done with the boiler and pump turned off.

The basic procedure is to pressurize your system through the manual lever of your feed valve and when it gets to about 25psi open your drain valve and bleed the air out.

Your feed valve has a little lever that looks like a flag. You lift that up to feed your system manually.

When done, lower that lever back to the auto position.

I don't know why you have 2 shutoffs but if they both go to the same place make sure they are open.(turned on).Don't worry about the cap on the bottom, it has nothing to do with what you're doing.

Keep the pressure high being careful not to go over 30psi until all the air is out and the water runs steady.

When you are satisfied the air is out, shut off the drain and then the feed valve.

You then drain off excessive pressure until you get down to 18-20psi.

When desired pressure is reached make sure all valves are open. Turn on boiler and test.


Enlarging your pic I see 2 boilers which is why you have 2 shutoffs. It looks like they have it set up so the boilers can be fed with either one.

Just open the ones that you have marked "C" and leave the others alone.

Hope this helps a little.
 
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Old 01-21-18, 04:52 PM
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Thanks for taking the time to write up that explanation. It helps a lot.

It's night now, so I don't think I'll be able to get a better picture of the piping until tomorrow. For some reason, a low res version of the piping system uploaded to the forum, but if you follow the link, you should see a slightly higher res version. I've also added a version of the photo where it might be easier to see what is going on. https://imgur.com/TzCuAtD

Is the valve marked A a shut off and drain or just a drain.
It's a shutoff and a drain. If you can look at the video at 0:20, the guy in the video shuts his off and attaches a hose to a drain above the shutoff later on. It's the same setup on mine, except there's only one pipe there.

Your feed valve has a little lever that looks like a flag. You lift that up to feed your system manually.

When done, lower that lever back to the auto position.
Is this the valve? https://imgur.com/MqMRrwu

Looks like it was in the "up"/on position when I went to the basement. So when I went down there to mess with it, it was set to manual. But the feed from the water supply (C) was also off.

So, in the end, are you saying that it should be turned to what would normally be the "off" position?

Am I trying to shut it off from the valve up top?

You then drain off excessive pressure until you get down to 18-20psi.

When desired pressure is reached make sure all valves are open. Turn on boiler and test.
Weil McClain seems to recommend a cold psi of 12. http://www.weil-mclain.com/sites/def...4-manual_1.pdf

Is it fine to go that far over it, especially before heating it up again? Just want to be super sure.

I'm also not sure how to drain off the pressure with the other valves off. So far, the only way I've been able to get it up or down is by adding or removing water.

Enlarging your pic I see 2 boilers which is why you have 2 shutoffs. It looks like they have it set up so the boilers can be fed with either one.
Each boiler has two shutoff valves for a total of 4. I still don't think I totally understand why there are 4 of them, since it seems like the same thing could be achieved with two. I'm not the smartest person, and I suspect the number of valves isn't entirely relevant to the process of purging the air out, but if someone can help me understand this, I'd appreciate it...
 
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Old 01-21-18, 05:48 PM
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Ok, so you have the same bleeding setup. You shut the valve off to stop the water from coming back up the return pipe when you bleed the air out.

Each boiler does have 2 shutoffs because that's just the way they did it. They fed the boilers from the middle line then split into each boiler. My guess is they just fed the boilers and put the first valve in to isolate each one until they were ready to pipe permanently.

You are right, they could have used just 2 but that doesn't matter. What does matter is that they are open.

The 12lbs is standard pressure and are what your feed valves come factory set at but you are better off running 18-20 for cavitation reasons in the pump. If you are uncomfortable with that pressure at least run 15psi.

To pressurize your system:
1) Shut off your shutoff valve on the return line
2) Open both blue valves on your supply and then leave them open. Your boiler should be at about 12psi if nobody has lifted the lever.
3) Lift the manual lever, you should hear water entering the system(pressurizing) fill to about 25psi.
4) At 25psi open your drain on your return line.
Maintaining that 25psi keep bleeding the system until all the air is out and the water runs clear. DO NOT be in a hurry. This could take a few minutes to make sure all the air is out. Your patients will be rewarded.
5) After you are satisfied all the air is out close the drain and put the lever back to auto on the feed valve.

At this point you will probably have about 25 psi in the boiler.

Open up your shutoff on the return line.

Open up your drain and let out enough water, a little at a time until you get to the pressure you want to run at. (I run mine at 20 and it's fine. It's what Taco pump Co. recommends), but it's up to you, but no less than 15psi cold pressure.

When all through make sure all valves are open except the drain and turn on the boiler to test.

I think I've answered everything, if not just ask.
 
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Old 01-21-18, 06:36 PM
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Thanks for the detailed instructions. I will try this tomorrow when I get off of work and I'll post to let you know how it goes.
 
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Old 01-22-18, 07:36 AM
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In the picture there is an air separator, and a air valve which removes air as it circulates. It looks like it has leaked water in the past. Itmay not be working. It should be replaced. Several brands available, I have goood luck with Taco. Lower the boiler pressure to near 0 psi, replace the air valve. Read the directions on the package. It is important to adjust the cap on the top [it looks like a tire valve cap] so that is open about a 1/4 of a turn, so as the air gets relieved, it won't drag along any bite of junk that might be around. Open the supply, and start it up.
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Old 01-22-18, 08:04 AM
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If you did need to change that vent on the air scoop there is no need to drain the boiler because it looks like you have a shutoff between the vent and the scoop.

Close the ball valve and unscrew the vent and replace, leaving the cap loose so the vent will self bleed.
 
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Old 01-22-18, 06:20 PM
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Based off what you're saying, I suspect it probably does need to be replaced. It doesn't even have the cap.

Looking at the air separator, it looks like that might have been leaking at some point too.


I haven't had any luck finding how-to videos on how to replace either one of these, but looking I'm guessing that they're both basically threaded, and plug in that way.
 
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Old 01-22-18, 10:03 PM
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That air separator looks fine. That rust is from the vent up top leaking. A very common issue. The vent just unscrews for replacement.


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Old 01-23-18, 11:36 AM
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To replace your air vent, shut off the ball valve and you just unscrew it as PJ said.

You may be able to do it with your hands but if not gently use pump pliers or a small pipe wrench being careful not to snap it off. That vent you have is cheaply made.

I would not use that kind again. Taco makes a good quality vent.

If you go to the sight below and type in TACO AIR VENTS in the search bar you will see what's available. (1/8" high vent)

Use a little pipe dope or tape being careful to stay away from the end with the tape so it doesn't break off and block the vent.

Just screw it back in hand tight and if it leaks just a slight turn with the wrench until it stops. Doesn't have to be super tight.

Leave cap loose for self venting. Open ball valve and put back on line. No need to bleed anything.

http://www.supplyhouse.com/
 
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Old 01-23-18, 09:55 PM
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Alright. Working on getting a replacement vent. Hopefully that part will be resolved by the end of the week. To be continued.

I tried doing some reading, and from what I gathered, the "auto" setting on the fill valve won't work correctly unless the air vent is functioning properly. Is that correct?

I ask because-- At some point, I had the two water supply valves open and the fill valve set to auto. I was expecting the pressure to maintain, but it went from 12 psi to 18. I'm guessing it's not supposed to do that, but I don't know .
 
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Old 01-24-18, 11:28 AM
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The vent has nothing to do with the feed valve working properly. You can leave the vent as is for now and then just replace it when you get one.

Your feed valve comes factory set at12 psi but that doesn't mean that someone hasn't adjusted it to 18 where is a good working pressure.

If it maintains 18 your good to go. If it keeps climbing you may have a defective feed valve which is why they may have had the valves shut off.
 
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Old 01-24-18, 02:19 PM
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Alright.

Assuming the supply valve is defective and assuming I only repalce the vent, what should I do?

- Leave the water supply closed
- Set the valve to auto anyway, so that it can still vent?

Can I leave it as is at that point, or would I need to set it to off/manual?

Is that wrong?
 
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Old 01-24-18, 02:45 PM
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Don't assume anything unless you want to be know as a parts changer. We are happy to help , put in the work and find your problem.

Follow post #14 and troubleshoot your system to locate the problem and fix it.

Since you have a ball valve to isolate the vent, change it at your leisure, it's no big deal as long as it's not leaking.

The rising pressure is your main problem right now.
1) shut off manual feed valve and leave your PRV in the auto position
2) Let the boiler cool and get your real cold pressure.
3) Start boiler and get up to temp and check pressure
4) If pressure is within a couple of pounds of cold pressure, leave manual valve off for a couple days for a good test.
5) You can now check your expansion tank as explained in #14. If your pressure is normal then chances are your tank is good but check anyway.

If after a couple of days things remain normal you can open up your MANUAL valve and see if water starts to feed in.

You can put the metal end of a screwdriver on the feeder and the other to your ear like a stethoscope to listen if you hear water entering, and also the pipe after the feeder will begin to feel cold from the fresh water feeding in.

If this happens either someone adjusted that valve to increase pressure or it is defective.

If the pressure continues to rise because of the feeder, shut off your MANUAL valve until you can replace it or as long as you know what's going on you can just leave the manual valve off and check it periodically.

As long as you locate the problem, other than the tank, neither one will not stop the world from turning.
 
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Old 01-24-18, 04:27 PM
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I appreciate your help. I'm posting these questions because I like to know what to do in a contingency and because I don't have a complete understanding of how all this stuff works together. I'm definitely not trying to replace the entire heater or avoid troubleshooting.

I assumed it was malfunctioning was because I did what you were suggesting in 14 when I got the boiler to 18psi. 18 was a figure I rounded down. I shut off the water supply when it was somewhere between 18 and 20 because it didn't seem like it was stopping and I wasn't sure how far I could push it or needed to. After seeing the comment about the climbing PSI, I wanted to try it again maybe up to 25, but I wasn't sure if there was a logical reason for it to be that high ( since the house + basement is 2 stories) or what the upper limit on the auto PSI would be.

But then I saw #12, and it seemed to imply that it would be possible to replace the vent and eliminate the need for bleeding. But I wasn't sure if this would be true even if the fill valve wasn't working.

But I was of the thought-- if changing the valve would take care of the noise, and work on a potentially broken valve, I could troubleshoot the valve at a slower pace, and maybe borrow a book about them from a library or something.

The heat works without the "auto" functioning, but the noise is the main problem. Is the auto totally necessary?

Currently, the pressure is ~16 psi cold and ~22 psi hot. Valve is set to auto but the water supply is off.

If after a couple of days things remain normal you can open up your MANUAL valve and see if water starts to feed in.
From past experience, manual with water supply on always gives water no matter the pressure of the system. 40psi at one point. Are you saying the valve should mitigate pressure even when it's set to manual? We're talking about this one, right?

 
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Old 01-24-18, 05:14 PM
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All I'm seeing in the pic is your air scoop with the ball valve between the air vent and scoop. That ball valve is what you close to change the vent and that is all it's there for. Once the vent is changed you open the ball valve and leave it open so the air can vent if needed.

End of story about that part of the system. Put it out of your mind for now.

I don't know what you are calling your feeder but I don't see a pic of it.

Go to the sight below and type in BOILER FILL VALVES and see what they should look like.

16 psi cold and 22 hot is fine but it should stay right there with all valves open. If the only way you can maintain that 16 psi cold is with the manual valve off then your feed valve either needs adjusting or is defective.

As I said, once everything is up tp temp open the manual valve, before the feed valve and see if water enters the system by feeling the pipe and watching the pressure. If it goes up or the pipe gets cold, close the manual valve until you can replace the auto water feeder.

http://www.supplyhouse.com/

Click on HEATING and then click on PRESSURE VALVES to see what is available.
Yours should look like one of those.
 
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