Need Help Bleeding Baseboards/Boiler

Reply

  #1  
Old 01-28-12, 07:45 PM
Member
Thread Starter
Join Date: Jan 2012
Location: USA
Posts: 7
Received 0 Votes on 0 Posts
Question Need Help Bleeding Baseboards/Boiler [PICS INSIDE]

I drained my hot water baseboard heating system today to replace a section of pipe and a baseboard. Upon refilling the system, I have heat in 2 out of 3 zones. The way I refilled it was I ran a hose from my outside hose to the boiler drain and ran water into the boiler until the pressure was around 15PSI. I then opened a hose fitting that I have in my attic and let the air out. I also opened the expansion tank and let air out until water flowed. When we discovered the cold zone we attempted to see if any air would come out of the red spigot, but none did. We also set that zone to OPEN to see if that would help, but no. Maybe I did it wrong . . .?

There are no bleeders at the baseboards. Just 90 degree elbows. I have three zones. One for the lower level (left in my picture), one for the middle level(middle in the picture), and one for the upper level (right in my picture). On top of the upper level there is an attic area that was refinished and there is a baseboard up there that has a hose fitting/valve attached to the end (no picture of this). This baseboard must be connected to either the lower or middle level because it was plenty hot, but my upper level just below the attic was not. This is the level where I replaced a section of pipe - about 6 feet with a 90 degree elbow that is above a bathroom I am renovating. Figured to replace it while it's exposed.

My question is how can I properly bleed the air out of the system so that my upper level will be hot? The baseboards and the line near the boiler coming from that level are somewhat warm, but I shouldn't be able to put my hand on it and leave it there. I can hear some water in the pipe returning from this level and the pipe is warm to the touch, but again, not nearly hot enough.

I know pictures help, so here they are. Thanks in advance!

Boiler Drain


Valves

This is really the picture I have that shows a lot. In the center are my three zones. They can be set to AUTO or OPEN. On the left you see the three zones returning to the boiler. They pass by the RED spigot/valve and then past the larger blue valve, through the circulator and into the boiler.

Maid-o-Mist
This is located on the same line that goes from the boiler to the 3 zones.

Expansion Tank

Valves2
Closer picture.

Return Lines
Closer picture. These run to the RED spigot and then to the blue shut off valve and then the ciculator. The one that is closest in the picture is the zone that is not getting hot.
 
Sponsored Links
  #2  
Old 01-28-12, 08:44 PM
NJT's Avatar
NJT
NJT is offline
Member
Join Date: Oct 2006
Location: USA
Posts: 23,539
Received 2 Votes on 2 Posts
For starters, CLOSE TIGHT the cap on that Maid-O-Mist. With your system and that type of expansion tank, you do NOT want to let air out of the system. Just close it and fuggedaboudit.

I also opened the expansion tank and let air out until water flowed.
Huh? Something don't sound right about that.

You do NOT want to let air out... there needs to be air in the expansion tank!

The type of tank that you have should be appx 1/2 full of water in normal operation. The proper method of servicing those tanks is to close a valve on the line leading to the tank and let ALL the WATER out of the tank. When it is COMPLETELY empty of water, then you close the drain and re-open the valve on the line leading to it. The system pressure will then PARTIALLY refill the tank, compressing the air inside the tank.

In the pics I don't see a valve leading to it, so wonder how you did what you said?

Is there a valve on the pipe from the boiler to the expansion tank?

Normally you shouldn't have to use a hose to refill the system, that green valve in the pic of the expansion tank should take care of that... BUT, you usually can't get much flow through them, at least not enough to purge the air anyhow...

So, hopefully you have TWO garden hoses handy.

Shut off the boiler and allow to cool to 100F or less. You don't want to feed cold water into a hot boiler... CRACK!

Connect one hose to the RED spigot and direct it to a floor drain, laundry tub, out a window.

CLOSE THE BLUE VALVE.

MANUALLY OPEN the zone valve that goes to the zone that's not working.

Connect the other hose to the boiler drain as if you were filling the boiler.

OPEN the RED drain.

OPEN the fill hose.

Water will flow through the boiler, out into the bad zone, pushing the air out through the red valve. When you see no more air, close the fill valve, close the red valve, open the blue valve, return the zone valve to auto.

The trick here is to CLOSE that blue valve. If you don't do that, the water won't flow through the zone, you need to force the water through the zone...

How much height is it from the boiler to the very highest radiator? Sounds like a three story? You may need more than 15 PSI in the system due to the height.
 
  #3  
Old 01-28-12, 08:53 PM
Member
Join Date: Dec 2008
Location: Northeastern, MN
Posts: 175
Received 0 Votes on 0 Posts
First thing the pros here will want some picture taken farther away so they can see how the pipes are going.

Second, The expanstion tank is not to be full of water. It needs and air cushion.
 
  #4  
Old 01-28-12, 08:57 PM
Member
Join Date: Dec 2008
Location: Northeastern, MN
Posts: 175
Received 0 Votes on 0 Posts
Trooper sure can type fast!!!
 
  #5  
Old 01-28-12, 09:34 PM
Member
Thread Starter
Join Date: Jan 2012
Location: USA
Posts: 7
Received 0 Votes on 0 Posts
Thanks for the quick reply. I am adding some more pics so you can see the line that runs from the expansion tank to the boiler.

I just closed the cap on the Maid-o-Mist. It was tight before and we wondered why. When I say I let air out of the expansion tank . . . what I did is after I filled the boiler via the drain valve, I closed it and then opened the valve on the expansion tank. Air hissed out, the water was black, then it flowed clear and I turned it off. We did let about a gallon or two out again because we knew the tank had to be half full and did not want it getting overfilled. There is air in it because I did hear it bubbling.

From what I see, there is not a shut off valve from the tank to the expansion tank. (see pics below)

I was just going to let the green valve do the work, but my dad suggested filling it quickly using the drain valve and a hose. Hard to say no to your dad!

So I am reading your method to bleed and want to make sure I got it right:

Shut off the boiler and allow to cool to 100F or less. You don't want to feed cold water into a hot boiler... CRACK!

Yeah, I knew to let it cool.


Connect one hose to the RED spigot and direct it to a floor drain, laundry tub, out a window.

OK

CLOSE THE BLUE VALVE.

OK

MANUALLY OPEN the zone valve that goes to the zone that's not working.

So this is the valve that has the wires to it? Slide it to OPEN? when I do this, the pump starts running. . . At least when I had it slid to OPEN earlier. Is this OK if the Blue valve is closed? It won't run it dry?


Connect the other hose to the boiler drain as if you were filling the boiler.

Do I run water into this one, or just let it flow outside/to a drain?

OPEN the RED drain.

Check

OPEN the fill hose.

Check


Water will flow through the boiler, out into the bad zone, pushing the air out through the red valve. When you see no more air, close the fill valve, close the red valve, open the blue valve, return the zone valve to auto.

Only question I have here is that there are other zones that are also directed to that red valve. Will this put any air into them or am I OK since those valves will be set on AUTO and not on?

The trick here is to CLOSE that blue valve. If you don't do that, the water won't flow through the zone, you need to force the water through the zone...

OK

How much height is it from the boiler to the very highest radiator? Sounds like a three story? You may need more than 15 PSI in the system due to the height.

It's a split level house, so there are a total of 4 levels if you include the attic. How high can I put it? I didn't want to damage anything.


MORE PICS:

Expansion Tank/Line


Tank to Boiler

Pressure Valve

Bleed Valve in Attic

Pressure and Temp (Was at 190 when heat was on. Night now.)
 
  #6  
Old 01-29-12, 08:18 AM
NJT's Avatar
NJT
NJT is offline
Member
Join Date: Oct 2006
Location: USA
Posts: 23,539
Received 2 Votes on 2 Posts
Trooper sure can type fast!!!
You should hear me send Morse Code!

I was just going to let the green valve do the work, but my dad suggested filling it quickly using the drain valve and a hose. Hard to say no to your dad!
No... Father Knows Best! Some systems have a 'bypass' around the fill regulator for this purpose, and newer fill valves have a 'fast fill' feature built into them. In order to properly purge the air from the zone you need a faster flow rate than your fill valve can provide. The hose hookup is the right thing.

when I do this, the pump starts running
Even with the boiler shut OFF ? (see first step)

If your pumps are wired to a separate circuit from the boiler, you will need to kill that power also. 'Usually' the pumps are on the same circuit. One switch kills all... usually...

there are a total of 4 levels if you include the attic.
But how many FEET? what's the altitude difference from the boiler to the highest piping?

The MINIMUM COLD fill pressure needs to be:

HEIGHT X 0.432 PSI + 4 PSI -or- 12 PSI, whichever is greater.

So, if it's say 30 feet from the boiler to the highest rad, you would need:

30 X 0.432 + 4 = 17 PSI MINIMUM, when the boiler is stone cold.

This would insure that you always have a POSITIVE PRESSURE at the highest point in the system.

How high can I put it? I didn't want to damage anything.
There must be a 30 PSI pressure relief valve on your system. I haven't yet looked at your added pics... but you must have one...

So, the MAXIMUM pressure on your system will be 10% less than 30, or 27 PSI.

The pressure will naturally rise as the water is heated. The function of the expansion tank is to control this pressure increase so that it remains below 27 PSI at all times.

Going to look at pics now...
 
  #7  
Old 01-29-12, 08:31 AM
NJT's Avatar
NJT
NJT is offline
Member
Join Date: Oct 2006
Location: USA
Posts: 23,539
Received 2 Votes on 2 Posts
I just closed the cap on the Maid-o-Mist. It was tight before and we wondered why
I can't say if it was installed for this purpose, but that would come in handy when filling the boiler. By loosening the caps when filling or re-filling the boiler, it would allow the air to escape ahead of the water. Regular drain valves are often used for this purpose... when filling the boiler, open the drain valve... when water comes out, close the valve, you know the boiler is full.

Air hissed out, the water was black, then it flowed clear and I turned it off. We did let about a gallon or two out again because we knew the tank had to be half full and did not want it getting overfilled. There is air in it because I did hear it bubbling.
Sounds like you are 'probably' OK then... if the pressure rises more than say 10 PSI when the boiler goes from COLD to HOT, then you might have to do something with it. As long as the pressure stays under control leave it be for the time being.

Not having a valve kinda makes difficult... there IS a way to use an air compressor though... but we'll talk about that later if need be. Our friend Furd would be the guy to tell you how to do that... I've never done it myself. You would need an adapter to hook the compressor to the drain on the tank.

I'm a little concerned about the proximity of the flue pipe to the combustible materials... is it as close as it looks?
 
  #8  
Old 01-29-12, 08:32 AM
NJT's Avatar
NJT
NJT is offline
Member
Join Date: Oct 2006
Location: USA
Posts: 23,539
Received 2 Votes on 2 Posts
(Was at 190 when heat was on. Night now.)
Did you happen to note the pressure when the temp was at 190?

By the way... those gauges are notoriously inaccurate. Yours looks sorta new... has it been replaced recently? Do you know it to be accurate?
 
  #9  
Old 01-29-12, 01:22 PM
Member
Thread Starter
Join Date: Jan 2012
Location: USA
Posts: 7
Received 0 Votes on 0 Posts
But how many FEET? what's the altitude difference from the boiler to the highest piping?

I'd say about 2 floors up, so 16 feet and then another 12 feet over to where the furthest baseboard is in the attic. So according to the calculation, 12PSI should do it if it is just based on altitude. It was around there to 15PSI prior to draining it.

There must be a 30 PSI pressure relief valve on your system. I haven't yet looked at your added pics... but you must have one...

The pressure relief valve is at 30 PSIG. So I will make sure it stays at 27.

Sounds like you are 'probably' OK then... if the pressure rises more than say 10 PSI when the boiler goes from COLD to HOT, then you might have to do something with it. As long as the pressure stays under control leave it be for the time being.

I will keep an eye on the pressure.

Did you happen to note the pressure when the temp was at 190?

By the way... those gauges are notoriously inaccurate. Yours looks sorta new... has it been replaced recently? Do you know it to be accurate?


The pressure remained constant at 15PSI when it was 190. I am guessing that it was replaced by the way it looks. We bought the house a year ago and the boiler was serviced/had burners replaced, so maybe they did the valve then.

I have a thread going somewhere else too and someone mentioned that the expansion tank could be isolated and drained if all of the system valves were shut off. Even with the blue valve closed and all of the zones closed, wouldn't water still run into it?
 
  #10  
Old 01-29-12, 03:29 PM
NJT's Avatar
NJT
NJT is offline
Member
Join Date: Oct 2006
Location: USA
Posts: 23,539
Received 2 Votes on 2 Posts
The pressure remained constant at 15PSI when it was 190.
That's very suspicious... I personally would not trust it.

You can verify the gauge fairly easily by making up an adapter to screw a pressure gauge onto the boiler drain. Just screw it on and open the drain...

Please see post #20 in the thread below so I don't have to retype it!

http://www.doityourself.com/forum/bo...ing-water.html

Even with the blue valve closed and all of the zones closed, wouldn't water still run into it?
Possibly... gravity is the main culprit at work here. If you are able to totally isolate all the piping above the boiler to prevent it from draining back into the boiler, and shut the blue feed valve(s) you may be able to drain the tank without the water from above flowing back in. Study the valves and such...

Something else you should know about draining those tanks... I call it the 'drinking straw analogy'.

Place a finger over the drinking straw and lift it from the drink. The drink will stay in the straw. Same effect happens when you drain the expansion tank.

When you hook up a hose to the drain, some water will drain out of course... and then it will stop, causing you to think the tank is empty, and in most cases, it is NOT. There is a vacuum above in the tank that is preventing the rest of the water from draining.

The use of the largest and shortest length of hose helps. If the hose is looped all over the floor, you will never get the tank drained. Air needs to find it's way back into the tank. Often loosening the hose on the fitting will let air in. Sometimes you need to remove the hose and use a bucket under the drain. You will read about people saying to blow into the end of the hose... I don't recommend that. You can use that air compressor though... but whatever you need to do to get it drained is what you would need to do.

We don't know that you need to... but without knowing if the gauge is working or not, you don't want to come home one day to find that the relief valve has spewed all over the basement!
 
  #11  
Old 01-29-12, 03:44 PM
NJT's Avatar
NJT
NJT is offline
Member
Join Date: Oct 2006
Location: USA
Posts: 23,539
Received 2 Votes on 2 Posts
By the way, one of the fellows answering your other thread doesn't understand about keeping your maid-o-mist closed... don't listen to him.

The guy that answered your last post is pretty much on, but I don't believe you need to purge all the zones. The less fresh water you introduce into the system, the better.
 
  #12  
Old 01-29-12, 03:51 PM
Member
Thread Starter
Join Date: Jan 2012
Location: USA
Posts: 7
Received 0 Votes on 0 Posts
Well, I followed directions and bled the boiler. All zones are hot!

The pressure right now reads 24 psi. It only climbed 4 lbs from cold to 190 degrees. I plan to get a gauge to check for sure at the drain. Is 24psi safe if that is the true pressure? If not, what is the best way to decrease the pressure? I really appreciate all the help! Does this forum take donations?
 
  #13  
Old 01-29-12, 04:11 PM
NJT's Avatar
NJT
NJT is offline
Member
Join Date: Oct 2006
Location: USA
Posts: 23,539
Received 2 Votes on 2 Posts
24 is fine if that's accurate. But I thought you were at 12-15 cold?

It only climbed 4 lbs from cold to 190 degrees.
What you're saying seems to indicate 20 cold, no?

what is the best way to decrease the pressure?
The pressure INCREASE when the boiler is heated is controlled by the expansion tank. With a correct cold pressure, and a properly sized expansion tank (I'm sure yours is) you shouldn't have to decrease anything. If you are only seeing a 4 PSI increase from cold to hot, I would say you don't need to worry about it...

Now, about the donations... lemmee borrow your Z28 for the weekend... KIDDING!

No donations, we're all volunteers. If we ever meet en persona, you can buy me a bunch of beers.
 
  #14  
Old 01-29-12, 04:42 PM
Member
Thread Starter
Join Date: Jan 2012
Location: USA
Posts: 7
Received 0 Votes on 0 Posts
I was at 12-15 originally the first way I filled it. After following the procedure you outlined it was higher.

Right now the boiler is not running and it reads 20 psi and 180 degrees. The pressure gauge I just screwed onto the drain reads 19 psi. So my gauge is accurate.

The Z28 is in the garage and not running-on it's way to be parted out eventually since I have a new house and another child on the way or else I'd give you a ride. I know what it takes to keep a forum going with bandwidth and all, so if we do meet, beers are on me! Where in Nj are you?
 
  #15  
Old 01-29-12, 04:59 PM
NJT's Avatar
NJT
NJT is offline
Member
Join Date: Oct 2006
Location: USA
Posts: 23,539
Received 2 Votes on 2 Posts
OK, I see... after you were done purging, you could have opened the drain and let a little pressure out of the boiler. I would run with 15 PSI when cold.

Good about the gauge then...

on it's way to be parted out
NOOOOOO! say it ain't so!
I guess you can make more on parts then selling the whole car though.
I help my bud wrench on his when he needs help... 69 Z28 R/S ... really nice... but off topic...

I'm ovah by de shaw.
 
  #16  
Old 01-30-12, 02:57 AM
Member
Thread Starter
Join Date: Jan 2012
Location: USA
Posts: 7
Received 0 Votes on 0 Posts
Well, went to bed last night and still can hear water rushing. All of the baseboards are hot to the point where I can't leave my hand on them, so I know I made progress yesterday. I'm pretty much at the point now where I may just call in a pro to get the rest of the air out. My wife is a light sleeper, so needless to say I am in trouble! What's a reasonable rate for someone to come out and make it right?
 
  #17  
Old 01-30-12, 07:25 AM
Member
Join Date: Feb 2011
Location: US
Posts: 552
Received 0 Votes on 0 Posts
You need a pro with a high head pump to get all the air out.
I could never get the air out of my third floor with the fast fill/purge method.
The oil guy came with a bucket, heater hoses and a small well pump and did each zone.
Took about 45 minutes or so. (8 zones)
The best part about the pump method, is very little new water is added. Mostly existing boiler water is recirculated.
Around here they are getting 130 an hour.

No point to pay someone to do the same thing you did.
Have pump will travel.

Peter
 
  #18  
Old 01-30-12, 02:27 PM
NJT's Avatar
NJT
NJT is offline
Member
Join Date: Oct 2006
Location: USA
Posts: 23,539
Received 2 Votes on 2 Posts
Maybe my recommendation to do just the one loop wasn't good... you probably got some air in the others as well.

When you do the purge, you want to get a good flow going in the zone, don't just let the hose trickle, open wide and say ahhhhhhh.

The thing about adding fresh water, and this goes along with what Peter sed, is that it contains LOTS of dissolved gases... and when that fresh water is heated, those gases separate from the water. It's a vicious circle. That's why the idea of using a pump to recirculate the water is a pretty good idea.

The thing is though, if you give it some time, the air that's in the pipes might find it's way back to the boiler and into the expansion tank where it belongs... but maybe the spousal pressure is too great to wait?
 
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
Display Modes
 
Ask a Question
Question Title:
Description:
Your question will be posted in: