air separator

Reply

  #1  
Old 07-06-12, 09:32 AM
J
Member
Thread Starter
Join Date: May 2009
Location: Canada
Posts: 94
Received 0 Votes on 0 Posts
air separator

Hello

As posted in another thread, I'm about to embark on some piping work on my hot water heating system. Because I'm draining the system down anyways, I want to get some other work done in the meantime. I've been told in the past that there's a pipe for an air separator on my boiler (Weil-McLein CGa Gold) that instead has a vacuum breaker on it. https://www.dropbox.com/s/apz6x8odvr...%2002%20AM.jpg

As you can see, it has some water leakage problems as well. Should I replace this? The system works fairly well as it is, so I don't know what I'm accomplishing by replacing it, but I still feel like I should.
 
Sponsored Links
  #2  
Old 07-06-12, 09:54 AM
J
Member
Thread Starter
Join Date: May 2009
Location: Canada
Posts: 94
Received 0 Votes on 0 Posts
Here's the system. In case that helps. https://www.dropbox.com/s/tqi6a201tc...%20diagram.jpg
 
  #3  
Old 07-06-12, 10:44 AM
lawrosa's Avatar
Super Moderator
Join Date: Dec 2010
Location: Galivants Ferry SC USA
Posts: 18,145
Received 60 Votes on 52 Posts
Take that vacuum breaker and throw it in the garbage.

Install a air vent at the top of that 1/2" nipple.
 
  #4  
Old 07-06-12, 11:29 AM
J
Member
Thread Starter
Join Date: May 2009
Location: Canada
Posts: 94
Received 0 Votes on 0 Posts
Heh, I was kinda looking for an explanation as to why, but honestly I'm definitely gonna do it regardless. Really the fact that it's leaking tells me to get rid of it, obviously.

How do you know it's a 1/2"? I measured the diameter of the pipe coming out of the boiler, it's 1"
 
  #5  
Old 07-06-12, 01:20 PM
lawrosa's Avatar
Super Moderator
Join Date: Dec 2010
Location: Galivants Ferry SC USA
Posts: 18,145
Received 60 Votes on 52 Posts
Well a vacuum breaker lets air into the system. Used for draining purposes. You don't want that.

A air vent lets trapped air out of the system. That pipe leads to a tapping that has a somewhat of a air separator built into the boiler. You can either cap it or install a air separator. But I don't know what other devices you have for air removal.

FV-4 Automatic Vent Valves, Air Vents, Water Safety & Flow Control - Watts
 
  #6  
Old 07-06-12, 01:42 PM
J
Member
Thread Starter
Join Date: May 2009
Location: Canada
Posts: 94
Received 0 Votes on 0 Posts
I have absolutely nothing installed for air removal, so I'm betting an air separator is in order. Thanks for your help. I'm also unclear on what size I should be getting. When you refer to the nipple, do you mean the lowest piece there? Here's a pic of the dimensions. It's actually closer to 3/4" by diameter.

https://www.dropbox.com/s/3zic07y6wo...%2035%20PM.jpg
 
  #7  
Old 07-06-12, 01:54 PM
lawrosa's Avatar
Super Moderator
Join Date: Dec 2010
Location: Galivants Ferry SC USA
Posts: 18,145
Received 60 Votes on 52 Posts
That pipe is 1/2". Air vents come with different size threads. If you can get one in 1/2" it will screw into that coupling. If you get a different size then you will need a reducer for the appropriate dimension.


Here is my tapping. I have a lot of other stuff on mine like water feed, relief valve, expandtion tank...etc. With air vent on top.


Name:  Picture 021.jpg
Views: 3416
Size:  42.3 KB











The reducer would look like this.


Amazon.com: Muellar #521-332HC 1/2x3/8 Black Coupling: Home Improvement
 
  #8  
Old 07-06-12, 02:13 PM
J
Member
Thread Starter
Join Date: May 2009
Location: Canada
Posts: 94
Received 0 Votes on 0 Posts
Awesome. Many thanks, I'll pick up a 1/2"
 
  #9  
Old 07-08-12, 10:34 AM
J
Member
Thread Starter
Join Date: May 2009
Location: Canada
Posts: 94
Received 0 Votes on 0 Posts
Ok, here's another question. My wife was picking this up for me at the local plumbing supply place, and they gave her a Spirotop. From the looks of this http://www.spirotherm.com/docs/brochures/Solar-1.pdf a Spirovent would be more what I'm looking for, wouldn't it? It's for solar systems, but would that really matter?
 
  #10  
Old 07-08-12, 11:04 AM
lawrosa's Avatar
Super Moderator
Join Date: Dec 2010
Location: Galivants Ferry SC USA
Posts: 18,145
Received 60 Votes on 52 Posts
You could put a spirovent but then you need to cut into the main heat line, then cap that vacuum breaker nipple. With the other vent you just need to remove what you have and add the air vent. The old saying "K.I.S.S"

You could really get into a whole repipe if you wanted.

I mean if you have rads and a bupass configuration it may not be piped correctly.

Better pics of your whole layout will help indeed. But how far do you want to take it?
 

Last edited by lawrosa; 07-08-12 at 01:10 PM.
  #11  
Old 07-08-12, 01:02 PM
J
Member
Thread Starter
Join Date: May 2009
Location: Canada
Posts: 94
Received 0 Votes on 0 Posts
Yeah that's always the question isn't it? For the time being I'm going to keep it simple. I'll see how the system performs over the winter and then maybe look at a repipe next summer if necessary. If I understand you correctly and the Spirotop is the simple way to just replace the vacuum breaker with the existing piping, then that's definitely what I'll do.
 
  #12  
Old 07-08-12, 01:13 PM
lawrosa's Avatar
Super Moderator
Join Date: Dec 2010
Location: Galivants Ferry SC USA
Posts: 18,145
Received 60 Votes on 52 Posts
You really need to describe your system better.

What type of heat emitters?

Do you have a boiler bypass? System Bypass?

Take pics and show your layout. The pros here will be more then glad to suggest things for you. But you need to show us and tell us.
 
  #13  
Old 07-08-12, 03:15 PM
J
Member
Thread Starter
Join Date: May 2009
Location: Canada
Posts: 94
Received 0 Votes on 0 Posts
Did you see the diagram I linked? https://www.dropbox.com/s/tqi6a201tc...%20diagram.jpg

IF I remember correctly that's a system bypass? I can take a few pictures later. I don't know about heat emitters though, how would I find that?
 
  #14  
Old 07-08-12, 05:50 PM
lawrosa's Avatar
Super Moderator
Join Date: Dec 2010
Location: Galivants Ferry SC USA
Posts: 18,145
Received 60 Votes on 52 Posts
Heat emitters" Radiators, baseboard....etc.

IF I remember correctly that's a system bypass?
Thats a boiler bypass if your pic is accurate and may not be beneficial in your situation as a residential home.

Pics? What do you want to do. or what are you looking to do?



 

Last edited by lawrosa; 07-08-12 at 07:17 PM.
  #15  
Old 07-08-12, 07:02 PM
NJT's Avatar
NJT
NJT is offline
Member
Join Date: Oct 2006
Location: USA
Posts: 23,539
Received 3 Votes on 2 Posts
Thats a boiler bypass
Look at the position of the circulator relative to the bypass... if the bypass is on the boiler side of the circ, it's a boiler bypass, if it's on the system side of the circ, system bypass. In this case it's a system bypass.

That bypass was installed to keep the return temp to the boiler up higher... to prevent flue gas condensation...
 
  #16  
Old 07-08-12, 08:20 PM
J
Member
Thread Starter
Join Date: May 2009
Location: Canada
Posts: 94
Received 0 Votes on 0 Posts
Yeah, my understanding is that it's not an ideal way to accomplish that goal, but it's 100% necessary. I have big ol' radiators. My only goal right now is to replace that vacuum breaker with the correct piece of equipment to effectively remove air from the system.
 
  #17  
Old 07-08-12, 08:25 PM
J
Member
Thread Starter
Join Date: May 2009
Location: Canada
Posts: 94
Received 0 Votes on 0 Posts
Ps I currently have the system drained from rerouting some pipes for a reno, so that's why I'm looking at doing this right now before I fill the system back up.
 
  #18  
Old 07-08-12, 08:39 PM
lawrosa's Avatar
Super Moderator
Join Date: Dec 2010
Location: Galivants Ferry SC USA
Posts: 18,145
Received 60 Votes on 52 Posts
So take some more pics and let us know what your doing!!!!
 
  #19  
Old 07-09-12, 01:03 PM
J
Member
Thread Starter
Join Date: May 2009
Location: Canada
Posts: 94
Received 0 Votes on 0 Posts
OK, here are some pics of the system. https://www.dropbox.com/sh/ace2qy13ktpemyb/qMlD3fn7Zh

The project I've done is replacing some of the pipes so I could take out a wall. I rerouted them around the wall that will now be open, using PEX.

Here's part of an email response from Spirotherm when I asked them about this. So it seems like I may need to do more significant work than just popping something onto the top of this pipe. The chart they reference is now in the folder I linked above.

"Assuming your drawing color code is red for HW supply, there are a couple reasons you could be having air problems. First it shows no air eliminator anywhere in the system and we’ll get back to that in a moment. Second, and quite often a cause for continuing air problems is the location of the expansion tank. While not always clear to installers, the tank should always be on the suction (inlet) side of the circulating pump. In other words, always “pump away” from the tank, never towards it. This is because of the point of no pressure change, which is a little complex to explain in an e-mail. Better location for the tank would be on the water feed line before the pump or anywhere on the line leading “to” the pump.

It appears the pump is on the return and pumping into and through the boiler. This complicates the ideal location for a Spirovent, so the next best location should be used unless you want to move the pump. Ideally it would be boiler, Spirovent on the outlet, followed by the pump as shown by “Recommended location” in the diagram below. This allows the Spirovent to scrub the air bubbles generated by the boiler temperature increase before they get to the pump. Leaving the pump where it is, the system would look like what is shown as “Acceptable location” in the diagram. In both cases the tank has to be on the inlet side of the pump.

As you will see, the Spirotop is only for a high point, which may not be possible in an older radiator system. Some old radiators have built in manual vents, which may need purged a couple times after filling the system, but after that the Spirovent should prevent any air from collecting in them. But, and we have to say this again, if the tank is left where it is, the system will probably not operate properly."
 
  #20  
Old 07-09-12, 03:28 PM
J
Member
Thread Starter
Join Date: May 2009
Location: Canada
Posts: 94
Received 0 Votes on 0 Posts
I'm gonna try to keep things simple here if at all possible, because if it's not necessary I'd prefer to avoid rerouting the whole system at this point. It works medium well, and I'd be willing to bet that it would work better if it had an air vent where it's supposed to have an air vent. The boiler manual describes having an air vent where that vacuum breaker is. Can anybody recommend an air vent for that purpose? I currently have a Spirotop that the local guys sold me.
 
  #21  
Old 07-09-12, 03:31 PM
NJT's Avatar
NJT
NJT is offline
Member
Join Date: Oct 2006
Location: USA
Posts: 23,539
Received 3 Votes on 2 Posts
I would use a 'Maid-O-Mist' #67 and adapt the pipe to the 1/8" thread with a bushing.
 
  #22  
Old 07-09-12, 03:33 PM
lawrosa's Avatar
Super Moderator
Join Date: Dec 2010
Location: Galivants Ferry SC USA
Posts: 18,145
Received 60 Votes on 52 Posts
Hopefully the pros will chime in and help out here.

That boiler bypass should be piped on the other side of the pump, and I don't know the implications but it may be working more as a system bypass.

I believe you lose more flow and heat through the rads with it like that.
 
  #23  
Old 07-09-12, 03:36 PM
lawrosa's Avatar
Super Moderator
Join Date: Dec 2010
Location: Galivants Ferry SC USA
Posts: 18,145
Received 60 Votes on 52 Posts
Troop you ever see a vacuum breaker on a boiler?????
 
  #24  
Old 07-09-12, 03:40 PM
J
Member
Thread Starter
Join Date: May 2009
Location: Canada
Posts: 94
Received 0 Votes on 0 Posts
Here's my theory: an air vent doesn't fit right there, it requires some piping away from the supply line in order to fit. A vacuum breaker, however, does. It seems like everything in this house has been done the cheapest and easiest way possible, regardless of the implications
 
  #25  
Old 07-09-12, 04:02 PM
lawrosa's Avatar
Super Moderator
Join Date: Dec 2010
Location: Galivants Ferry SC USA
Posts: 18,145
Received 60 Votes on 52 Posts
an air vent doesn't fit right there, it requires some piping away from the supply line in order to fit. A vacuum breaker, however, does.
I disagree. If anything the vacuum breaker takes up more room.


 
  #26  
Old 07-09-12, 04:13 PM
NJT's Avatar
NJT
NJT is offline
Member
Join Date: Oct 2006
Location: USA
Posts: 23,539
Received 3 Votes on 2 Posts
Troop you ever see a vacuum breaker on a boiler?????
No, I suspect that a previous homeowner replaced that and just simply didn't understand the difference.

It's hard to gain perspective in the photos, but I'm willing to bet that the MOM will fit there.

J, what's the boiler model again?
 
  #27  
Old 07-09-12, 04:18 PM
J
Member
Thread Starter
Join Date: May 2009
Location: Canada
Posts: 94
Received 0 Votes on 0 Posts
Right, i was gonna edit that, cause the MOM does look like it'll fit, just this Spirotop won't.

It's a Weil-McLain CGA Gold
 
  #28  
Old 07-09-12, 11:11 PM
J
Member
Thread Starter
Join Date: May 2009
Location: Canada
Posts: 94
Received 0 Votes on 0 Posts
OK, I just read the boiler manual carefully and learned a bunch. You're right, lawrosa, it's actually a system bypass, because of the location of the circulator. NJTrooper, I believe the reason your explanation doesn't hold true is because the circulator isn't on the supply side. In my setup it's on the return side. If you're interested in this, check out pages 22-25 of the manual, which I have in the folder linked above or here https://www.dropbox.com/s/mu40k74jrb...r%20manual.pdf

Lawrosa you are also correct about this resulting in lower flow, and higher temperatures. The manual doesn't talk about whether it's less efficient, although I would imagine it is, because of heating the water more. It only mentions a possibility of uneven heat, which we have experienced to a degree, but like I said it's been manageable with extensive bleeding, and I was hoping adding an air vent would help that.

Another problem is, my system is still not piped quite correctly according to page 25. My expansion tank should be on the fresh water supply line. Any idea how big a problem this is? Maybe I should actually look at completely repiping the near boiler stuff, if it's gonna even out my heat AND make it more efficient?
 
  #29  
Old 07-09-12, 11:42 PM
lawrosa's Avatar
Super Moderator
Join Date: Dec 2010
Location: Galivants Ferry SC USA
Posts: 18,145
Received 60 Votes on 52 Posts
Hmm I think I meant to say system bypass...

That is what you have. Look at figure 17 page 25. Shows the circ on the return or supply. Both configurations are a system by pass. The water leaves the boiler and some goes right back into the boiler hence by passing the system.

Figure 14 page 23 shows the boiler bypass.

( That, I believe, is how you want your system piped. ) It will slow the flow through the boiler to keep it hot and increase the flow through the system (rads)
 

Last edited by lawrosa; 07-10-12 at 12:21 AM.
  #30  
Old 07-09-12, 11:50 PM
J
Member
Thread Starter
Join Date: May 2009
Location: Canada
Posts: 94
Received 0 Votes on 0 Posts
Oh my mistake he totally did say system bypass, and the circ can be on return or supply. Oops. Just goes to show what happens when I start thinking I'm getting the hang of this stuff
 
  #31  
Old 07-10-12, 04:51 AM
NJT's Avatar
NJT
NJT is offline
Member
Join Date: Oct 2006
Location: USA
Posts: 23,539
Received 3 Votes on 2 Posts
Right... as far as the bypasses go, it doesn't matter which side the pump is on, the net effect is still the same.

System bypass will always shunt flow from the radiators, and this is what can cause the lower flow and imbalance issues in the heat distribution.

It protects the boiler by mixing some hot supply with the returning cool return in effort to keep the delta T across the boiler smaller.

Boiler bypass also protects the boiler but in a different way. By slowing the flow across the boiler the delta T from return to supply is actually GREATER. You still have the cool water returning, but the AVERAGE temperature in the boiler is caused to increase and this protects the boiler in much the same fashion.

A boiler bypass still allows full flow through all the radiators and the net result is that the heating is more balanced.

=====================

There are literally MILLIONS of systems that are not piped 'by the book'. I don't know that I would make extensive changes to the near boiler piping at this point with your system. How long has it been working 'satisfactorily' ? You might opt to wait until a new boiler is on the ticket to make the changes... but without knowing a 'history' of the system performance, it's a tough call to make.

The whole concept of 'pumping away' is fairly recent and many techs have no idea what it even means. Only in the past few years have the 'alternate' locations for the tank and pump been appearing in manufacturer's install documents.
 
  #32  
Old 07-10-12, 10:22 AM
J
Member
Thread Starter
Join Date: May 2009
Location: Canada
Posts: 94
Received 0 Votes on 0 Posts
Thanks NJ, I'd prefer to not have to make the changes so that's a welcome opinion. One thing I'd consider is if I was going to save a lot of money in heating, the extra work could very well be worth it. I'm in Canada, so we use a lot of heat, but natural gas is also pretty cheap.

I've had the house for three winters. 2009-2010 everything was fine except the 2nd floor was pretty warm and the third floor rad at first had no or little heat. Some bleeding helped, and my contractor replaced the expansion tank.

Over the summer I insulated the basement and attic, which helped keep the system from having to work too hard, so the 2nd floor was no longer as hot. In 2010-2011 I bumped up the water pressure from 12 to 18 psi, and then we had heat in the third floor, but it wasn't very warm yet when the weather was medium cold, whereas when it got very cold outside the third floor got SUPER hot. Windows were opened in -30 degrees Celsius weather.

In 2011-2012 we didn't really have that kind of cold weather so I didn't experience the super hot third floor, it heated fairly well overall. On the other hand a couple of radiators on the 2nd and 1st floor stopped working, which is when I drew that diagram with the relative temperatures of the rads displayed. Because of the location of those rads the net effect wasn't that bad, and again, doing some heavy bleeding of the system seemed to help that problem.
 
  #33  
Old 07-11-12, 06:34 PM
rbeck's Avatar
Member
Join Date: Jul 2007
Posts: 2,482
Received 5 Votes on 4 Posts
If the system is drained or will be drained before winter I would change the piping to make it right. I usually am of a different mindset than most here. The reason I would re-pipe is that you are not getting rid of the air which means the pump head changes, flow slows down, less heat from radiation, the make-up water is in the wrong place, bypass is a system not a boiler bypass and no air seperator. The pump by the manufacturers was asked to be moved in 1958 as close as I can tell when the industry introduced the first 1 piece pump. The little one piece pump uses added system pressure to get rid of air. You can only do that when you pump away from the expansion tank connection with the little one piece pumps.
See links
Bypass_Piping_Explaination
Hot water heating systems FAQ
 
Reply
Posting Rules
You may not post new threads
You may not post replies
You may not post attachments
You may not edit your posts

BB code is On
Smilies are On
[IMG] code is On
HTML code is Off
Trackbacks are Off
Pingbacks are Off
Refbacks are Off


Thread Tools
Search this Thread
 
Ask a Question
Question Title:
Description:
Your question will be posted in: