Bleeders on forced hot water system

Reply

  #1  
Old 10-13-06, 06:39 AM
B
Member
Thread Starter
Join Date: Feb 2004
Posts: 16
Received 0 Votes on 0 Posts
Bleeders on forced hot water system

Hello folks, I have a vintage 1960's hot water boiler, with Slant fin registers, It is a single loop system in a ranch style home. My question is this. This system had no bleeders on the baseboards, so, last year i installed one bleeder on one of the furthest baseboards from the boiler, should i install more bleeders? The system doesn't seem to be heating the rooms like it should. so this leads me to believe there is air in the loop. Any help or ideas would be appreciated, Thanks
 
Sponsored Links
  #2  
Old 10-13-06, 06:40 PM
Grady's Avatar
Forum Topic Moderator
Join Date: Jan 2005
Location: Delaware, The First State
Posts: 14,247
Received 23 Votes on 21 Posts
Bleeders

To install bleeders or not depends on the piping configuration of your system. If you have a mono-flo or diverter tee system, bleeders (air vents) are needed on each section of baseboard. If the system is a continous loop, you need only a purge station near the boiler. A continous loop is easy to determine. If the main pipe out of the boiler goes only as far as the first piece of basebord, you have a continous loop.
If there is an unbroken pipe which circles the entire basement, or at least down a whole wall & on back to the boiler with two tees going to each section of baseboard, you have a mono-flo tee system.
 
  #3  
Old 10-14-06, 06:22 AM
B
Member
Thread Starter
Join Date: Feb 2004
Posts: 16
Received 0 Votes on 0 Posts
more info

Thanks for the reply grady, some more info on my sysytem, Its a continous loop, one copper pipe going around the perimemeter of the house. I am wondering why i am losing so much of the heat, the pipe coming out of the boiler is too hot to touch, the return pipe is lukewarm, is it possible to lose that much heat? thats what makes me think there is air in the lines, I replaced the circulator pump about a year ago, this may sound stupid but, is there anyway i could have installed it wrong? does it matter which way the pump is pushing the water? Maybe an expansion tank problem? i'm stymied here. Thanks again, Jim in steeler country
 
  #4  
Old 10-14-06, 03:10 PM
Grady's Avatar
Forum Topic Moderator
Join Date: Jan 2005
Location: Delaware, The First State
Posts: 14,247
Received 23 Votes on 21 Posts
Bigguy

Just so I'm sure what type of piping system you have: The pipe leaves the boiler & goes to the first section of baseboard, out of that section, & into the next, & so on around the perimeter of the house. After the last section the pipe goes to the boiler. There is no pipe with a bunch of tees, just elbows. Correct?

Is the circulator on the pipe which comes out of the top of the boiler or on the one going into the bottom?
There is usually an arrow cast into the circulator housing. Which way does the arrow point?
 
  #5  
Old 10-15-06, 06:43 AM
B
Member
Thread Starter
Join Date: Feb 2004
Posts: 16
Received 0 Votes on 0 Posts
continous loop

Grady< thanks again, I have one big loop, no tees at all, just elbows that go up to each baseboard, I looked at the circulator pump, the arrow is pointing down, going into the back of the boiler, this morning i checked my thermostat, it was set on 70, and the house temperature was a chilly 64, my kids are starting to complain!, Any ideas?
 
  #6  
Old 10-15-06, 06:45 AM
B
Member
Thread Starter
Join Date: Feb 2004
Posts: 16
Received 0 Votes on 0 Posts
circulator pump

I forgot to tell you the pump is on the bottom pipe of the boiler, with the arrow pointing down
 
  #7  
Old 10-15-06, 10:57 AM
Grady's Avatar
Forum Topic Moderator
Join Date: Jan 2005
Location: Delaware, The First State
Posts: 14,247
Received 23 Votes on 21 Posts
Air

The easiest thing would be to install a purge station on the return ahead of the circulator. This would allow you to purge the whole system from one place. You need a shut off valve (preferably a ball valve), a tee, & a boiler drain valve. A photo of the return in the area of the circulator would help. Photos can be posted on photobucket or similar web site & a link provided here.
 
  #8  
Old 10-17-06, 04:30 PM
B
Member
Thread Starter
Join Date: Feb 2004
Posts: 16
Received 0 Votes on 0 Posts
purge sytem

I have a puge valve on this sytem, i purged the sytem yesterday, but not much air came out, back to my original question, shouldn't the return pipe be almost as hot as the supply coming out? Is it possible i still have air in one of my baseboards, and should i install more bleeders? i'll have one of my kids try to post some pictures of my boiler, thanks for everything
 
  #9  
Old 10-17-06, 06:04 PM
Grady's Avatar
Forum Topic Moderator
Join Date: Jan 2005
Location: Delaware, The First State
Posts: 14,247
Received 23 Votes on 21 Posts
Return Temp

Yes, after a little while the return temp should be quite hot.
It is possible you still have air. A couple of questions if I may: When you purged the system, did you close the shut off valve between the boiler & the purge valve? If the valve was left open, the water will flow backward thru the boiler rather than thru the loop. About how much water did you purge? It often takes 15-20 gallons.
If it seems you did all of this, I think more bleeders would be in order. I suggest them on the "discharge" end of each piece of baseboard, or wherever the pipe drops back down to below the floor.
 
  #10  
Old 11-02-06, 07:10 AM
B
Member
Thread Starter
Join Date: Feb 2004
Posts: 16
Received 0 Votes on 0 Posts
bleeding baseboard

good morning folks, in reading some of the other posts about bleeding baseboards i came across something, after i installed the one bleeder, should i have bled that baseboard until i had hot water coming out? and should i do this while the circulator pump is running? thanks again, Jim in steeler country
 
  #11  
Old 11-02-06, 08:37 AM
Grady's Avatar
Forum Topic Moderator
Join Date: Jan 2005
Location: Delaware, The First State
Posts: 14,247
Received 23 Votes on 21 Posts
Bleeding

Trying to remove air from a system is often a lot of trial & error. Sometimes it works better with the circulator on, sometimes off. I always start with the system static (circulator off). As to getting hot water out of the bleeder, it would depend upon where the feed water comes into the system. If the feed is on the boiler discharge, the more you purge, the colder the water will get.
 
  #12  
Old 11-02-06, 09:57 AM
X
Member
Join Date: Nov 2005
Location: USA
Posts: 2,459
Received 0 Votes on 0 Posts
Respectfully submit that if you don't hear air noise in a series loop system, but still have a problem heating the space, then the problem lies in one or more of 1) the flow rate is inadequate and all the BTUs are being consumed early in the loop, 2) the BTUs required for the total amount of element exceeds the output of the boiler, or possibly 3) the pumping configuration. Or maybe just 4) the boiler output temperature is too low.

I have run my series loops about 75% full of water, by accident once. The air noise was unbelievable but they still heated the space. I think you've got one or more of the problems listed above.

If you can measure the supply and return temps, that would be a start. The ideal system (rarely if ever achieved in reality) has a 20F difference in supply vs return temps.

Series loops really should not have any other air control beyond that near the boiler. Exceptions would be for bizarre piping configurations that go over/under odd joist arrangements and create physical traps. The normal up/down of piping to/from baseboard elements is easily rid of air with the proper flow velocity (2-4 ft/sec or about 3.2-6.5 gpm in 3/4" copper pipe) and air elimination system (air scoop, spirovent, boiler-provided air vent tapping).

How many feet of straight pipe (including baseboard element), and approx how many elbows in the loop? what kind of pump? how old? How many feet of finned element? what is the boiler output rating?
 
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: