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My fin-pipe radiator heat sucks

Post in 'DIY and General non-hearth advice' started by tiber, Oct 21, 2010.

  1. tiber

    tiber New Member

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    Long story short, I had the furnace cleaned by some jackasses and I suspect there's a lingering problem. Without going into too much detail to the politics of it I'm left to fix it, myself.

    I have an older, oil fired furnace or boiler. As I don't believe it has a tank I don't think it counts as a boiler, but whatever. It's got a bright red old style steel expansion tank. Downstairs, it seems fine. Upstairs the hot water doesn't seem to get to all the rooms. My sons room gets the most heat, when this thing kicks over it'll go from 60F to 80F in a matter of nothing flat. The master bedroom hardly gets any heat at all. I'm pretty sure, especially given the abuses it's suffered from the "technician", that it's got air in the lines. Now, the radiators in my folks house have bleeder valves. Air gets in there, you open the bleeder valve, stuff is once again happy. These are those "fin pipes" on the baseboard, they don't appear to have bleeder valves.

    HOW DO I GET THE AIR OUT?

    I read this: http://homerepair.about.com/od/heatingcoolingrepair/ss/trblsht_boiler_4.htm

    It doesn't particularly describe my problem but it's something to check. I'm really at a loss as to how to get the air out though. I almost read it as "make sure it's at 12PSI and the air will enter the water" but this probably isn't how that works.

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  2. benjamin

    benjamin Minister of Fire

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    If you're talking about a sheet metal baseboard unit that has a copper pipe with aluminum tubes in it, then look at each end, there should be a vent at one end, especially on a two story house.
  3. fdegree

    fdegree Feeling the Heat

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    My experience is at the commercial level...not sure if there is anything all that different at the residential level, except everything is smaller.

    12 psi is not necessarily the pressure you may need. 1 psi = 2.31 feet of water. So, determine how high the highest point is above the pressure gauge...divide that by 2.31...then add 5 psi for the horizontal sections of pipe. This should be the pressure requirement at the gauge. Example...boiler in basement with the pressure gauge you are referencing at 5' above the floor...4' above that pressure gauge is the level of the piping on the 1st floor...9 feet above the 1st floor piping is the level of the piping on the 2nd floor...so, the total distance from the pressure gauge to the 2nd floor piping is 4'+9'=13'...13/2.31=5.6...5.6+5 =10.6...in this example you should fill the system until the pressure gauge reads 10.6 psi. Being a little higher is no big deal as long the pressure relief valve can handle the added pressure...keep in mind, as the water heats up, the pressure will increase. So, if you don't have a basement and 2 floors above that, you will not need that much pressure.

    Now, as for your problem, it does sound like you have air in the system...without bleeders, it is challenging to get the air out. First of all, heat the water up...it is easier to force air out of hot water than cool water. If your pressure relief valve can handle it, temporarily increase the system pressure to help force this air out...be sure to let some water out, after the you get the air out, to get the system pressure back down to the needed operating level.

    Can you close off all the water flow to all of the rooms, except for one? This way the pump can force all it its pressure through that one room...hopefully forcing the air out. Do this for a couple of hours to each room in your house...hopefully forcing all of the air out. This air needs to go someplace...you should have an air separator near the boiler, or at least some way for the air to get to the expansion tank. Make sure your expansion tank is not waterlogged nor completely filled with air...hopefully there is a sight glass on the expansion tank...get that sight glass so it is 1/4 - 1/2 full of water...the rest should be air.

    I hope this makes sense...
  4. fbelec

    fbelec Minister of Fire

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    the majority of baseboard heat that i've seen around here, the baseboards were installed without bleeders. once and while you get a guy that installed it with, but not to many. also if your system is linked one room to the other (one big loop) you can have temperature differentials if they didn't compensate for the heat loss in the last room with more fin. the right way to install heat in monoflow tee's. one big loop from boiler back to the boiler with monoflow tee's at every baseboard or radiator.
    to get the air out you'll have to run a hose outside or to a big sink. run as much pressure thru each heat zone as you can without blowing off the pressure relief valve. about 30 pounds pressure. if you have multi zones shut of all zones but the one your bleeding, it should work. the only time i've seen that not work is when some dummy puts in a large cast iron radiator without bleeders. can't get enough pressure and water flow from a 1/2 in water feed to bleed them
  5. ROBERT F

    ROBERT F Minister of Fire

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    air/water seperators are all my system has, and it just takes time to bleed all the air. of the 3 days I used the boiler last year half the first day was making sure all the air was out.
  6. billb3

    billb3 Minister of Fire

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    I had one of those older style tanks that were suppsoed to be half full of air that would constantly get water-logged and I'd have to bleed the radiators every couple days, one in particular.
    Had a tiny enough leak that it would not drip on the floor.

    There's an awful lot of ways for air to get into a system.
    From a circulator pump gasket to leaks in the boiler that you might not even see in the burner smoke.

    I recall an older house with fin on copper not having bleeders and using a garden hose on each zone , but it's been too long since I did it to remember anything more than water going down the driveway.
  7. tiber

    tiber New Member

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    So I'm still not clear on the procedure here.

    I double checked the master bedroom, it's not no bleeders. It does have a valve which is obviously for proportioning but after pulling out all the furnature there's no bleeder. I opened the proportioning valve a bit more.

    So I have this expansion tank, and I've checked the pressure gauge on the boiler (12PSI). The tank doesn't have a sight glass. From what I can divine, I'm supposed to... turn off the feed to the tank and half fill it with water?
  8. fdegree

    fdegree Feeling the Heat

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    Apparently, residential equipment is a little different than what I'm use to seeing commercially. So, hopefully some of the other folks will help you more than I can.

    Regardless, you have to get the air out...this will involve either bleeding (which you apparently can't do) flushing (perhaps using a garden hose), or forcing the air to an air vent near the boiler or expansion tank.

    Since you don't have bleeders, lets discuss flushing. Find someplace you can hook up a garden hose... preferably on the leaving water side of your radiator. If you do have such a valve, simply hook a garden hose to it...open your fill water valve near your boiler to keep water entering your system, and let the radiator flush until the air is out. Do this to each radiator in the house until they are all air-free.

    But, you may not have such a valve on your radiator. If not, look around your boiler...hopefully there is a place to hook up a garden hose. Depending on where the garden hose hook up is, in relationship to the fill water, you may still be able to flush each radiator individually. Check you piping to determine where the fill water is likely to go if you start flushing...make sure the fill water is not simply going right back out the garden hose. Hopefully, you can close the valve on every radiator in the house except one...open the fill water and let it flush out the radiator that you have open, and through the garden hose until all of the air is out...repeat this for every radiator in the house.

    Perhaps you have already seen this, but here is a link to how you can recharge the expansion tank...if that is needed...it is possible your expansion tank is fine and all you have to do is get the air out:
    Recharge Expansion Tank

    Hope this helps...
  9. tiber

    tiber New Member

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    So I am looking at http://homerepair.about.com/od/heatingcoolingrepair/ss/boier_exp_tank_2.htm

    I'm not sure what the difference is between a combination valve and simply having a valve on the tank. I've got a spigot on this tank but it's to one side.

    If I understand what we're trying to do, I need to turn on the pump (heat), open the water-fill valve, then open the expansion tank and just let the water flow out until it flows smoothly? If I understand the system correctly, the fill feed will push the water around in the pipes, this will push the air down the pipes to the tank, and the tank must be open. While the water is moving air into the tank it will likely be making spurting or burping noises, wait until these stop and then close the tank and fill until the system is at 12PSI. Then magically the air in the tank won't somehow get back into the radiator?
  10. btuser

    btuser Minister of Fire

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    Sounds like you've got a boiler with a tankless coil in it. Have you recently changed your auquastat temps? Because a lower high limit may be leaving your room too cold. You're circulator could also be stuggling and therefore increasing the delta of the loop. What makes you think its air?

    If you've got a valve on the radiator for a hydronic loop its either a monoflow system or a split tee system. If its a monoflow there should be bleeder valves on each radiator, so I guess this is out. A split tee system will split the water in two directions and then come back to a single return, which is handy to even out loop temps on a long run. Does your son's room have a valve as well, and for that matter does every register have a valve? Because this would mean it is a monoflow and explain why its airbound, because monoflow systems are very prone to that.

    Verify the temperatures of the supply and return for that zone. If the difference is more than 20 degrees it may be the circulator, or too great a differential for the boiler. If that proves negative, it sounds/looks like a monoflow heater that's airbound. You can try purging the zone, but you're just going to introduce more air to the sytem again so I'd cut in a bleeder valve/elbow.
  11. fdegree

    fdegree Feeling the Heat

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    btuser has a point, especially if you think this will become a problem again in the future...install a bleeder valve elbow. This is a copper elbow with a hole on top of the elbow that has female threads...you can screw a bleeder port into those female threads...providing a place to bleed the air.

    I'm not sure it would be a good idea to flush from the expansion tank...maybe someone else has some thoughts on that.

    Do you have a spigot someplace else?

    If you have the style of expansion tank as shown in the picture from your last link, you may be able to get the air out without using a garden hose. Try the same procedure...close all radiators, except one...turn on the pump...over pressurize the system a little by opening the fill valve (maybe 20 - 25 psi, don't exceed the pressure relief valve rating). Allow the water to force itself through the radiator that is open...forcing the air out, hopefully making its way to the expansion tank, instead of out a garden hose. Repeat this with each of the radiators in the house. After you feel all of the air is out, you may have to go through the re-charging procedure of the expansion tank, as described in your last link.

    A few hints:
    you may be able to hear the air is it is moving through the pipes
    you may be able to tell how how much water is going through your radiator by throttling and opening the valve on the radiator and listening for moving water sounds...this may give you an idea if all the air has been forced out.
    if you can open and close the valve on the radiator quickly, you may be able to create a surging sensation...helping to break the air loose and get it moving out of the radiator.
  12. tiber

    tiber New Member

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    Yes his room has a valve. I haven't verified the rest of the fin pipes but I believe they all have the proportioning valve (and no bleeder nipple).

    I guess the question is "why do you think it's air?" When the hamfisted idiot came in to clean the burner, etc for it's yearly service, he tripped in the crawlspace and (among other things) broke one of the hot water lines which I eventually came to believe went to the radiator. He left my wife and kid (I wasn't home) with this thing dripping all over the floor and while it didn't put out buckets of water, there was a significant mess me left me with to clean up in the crawlspace. (No I didn't pay them). I ended up resoldering the joint and managed to get enough solder on there to seal it. After that it had an overpressure condition, which eventually corrected itself. Also the feed from the watermains was leaking and I redid the joints on that. In short, there was a lot of chance to get air into the system, but I've got no idea how to get it back out. The pipes bang now too and I have nitemares about them moving around and their solder joints giving up.

    I'll look around for another spigot when I get home, thanks for sticking with me on this.
  13. vvvv

    vvvv New Member

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    i built a 1cheeked system once & ended up covering sections of the fintubes with towels to get the hot water further down the line
  14. benjamin

    benjamin Minister of Fire

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    You might be able to loosen the packing on the valve to bleed the air out, at least enough to get the water circulating with the other valves closed, then it will flush itself out.

    I've seen baseboards with "icemaker valves", the self piercing thingies that clamp onto copper pipes, can't recommend it, but I can see the advantages.
  15. btuser

    btuser Minister of Fire

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    This is an awesome idea, and may be why the original installer didn't install them in the first place. The water psi should push enough air out to get water circulating through the monoflow tees.

    Just don't try too hard and snap off the valve.......Done it!
  16. fdegree

    fdegree Feeling the Heat

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    That's an interesting idea...never crossed my mind. Most certainly worth a try.

    as btuser said, be careful...you don't want to break anything.


    As for the "ice maker" valves...we have always called them saddle valves. I have only seen them used on refrigerators...in this application they tend to leak quite frequently. They are OK to use for temporary purposes, but after the problem has been diagnosed and repaired, they should be removed and the hole they leave behind should be repaired. I have no idea how reliable they might be in this heating situation.
  17. btuser

    btuser Minister of Fire

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    Saddle valves stink. However, that's when used on a 60 psi water line. A copper line with 12-15 psi shouldn't be much of a challenge for one of these "vampire valves", plus your going to close it and not leave it open like it used for an ice maker. Worth a shot if its a pain in the A**. Just don't try it on black pipe.
  18. tiber

    tiber New Member

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    Wait so walk the nut out the entire way down the stem, and see if it'll bleed out the air?
  19. btuser

    btuser Minister of Fire

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    I'd try backing out the valve first. if push come to shove try the saddle valve. Put a 3/8" hose on it and then you can bleed into a bucket.
  20. fishingpol

    fishingpol Minister of Fire

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    Tiber
    I have a forced hot water system, gas-fired boiler. I do get air in some of the time and I do bleed the air out on occassion. Just a few questions.

    1.) Do you have a drain spigot at the end of the zone before it returns to the boiler?
    2.) If so, is there a shut-off valve after it before the return header pipe?
    3.) Do you have a hi-vent valve either on top of your boiler, or over your expansion tank? (It is a brass canister about 4 inches high.)
    4.) Do you have a fast-fill valve on the copper feed line to your boiler? It is usually gray with a flat flippy called a vane.
    5.) Do you have a zone valve that opens the loop for each zone?

    If you have some of these, I can give you some pointers. I had a plumber friend of mine show me a good way to purge air out of the lines.
  21. Don2222

    Don2222 Minister of Fire

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    Hello

    Here are some pics of my Oil boiler (Boiler is heated water to make room heat by hydronic thermal conduction - 180 degrees, so not quite the H2O boiling temp. LOL)

    1st pic
    Auto or Fast Fill Valve - Red arrow points to lever. When lever is push so it is straight up, more water will be added to the heating zones faster.

    2nd pic
    Zone bleeder next to Boiler.
    To Bleed
    Shut off Boiler
    Shut off Zone Valve - Yellow Handle
    Unscrew cap and Connect Garden Hose to Faucet and open Spigot

    Air should come out of hose with water.
    When there is no more air in water exiting hose, zone has been bleeded!

    Close Spigot
    Disconnect hose and screw cap back on.
    Open zone valve
    Turn Boiler back on!

    Note: I have separate circulators for each zone
    If you have zone valves then you must open the zone you are bleeding by turning up the thermostat for that zone to open the zone valve

    That is it. Hope this helps!

    Attached Files:

  22. fdegree

    fdegree Feeling the Heat

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    I'm not exactly sure what type of valve you have...pics might help

    Depending upon what you have, you may just need to loosen the nut until you hear air and/or see water coming out from around the nut. Try to have something under the valve to catch the water.
  23. fbelec

    fbelec Minister of Fire

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    just to add to don2222 post. when you have the hose stuck out the door to drain and you can't see the air you can hold the hose in one hand bent but not kinked to restrict the flow. if a air bubble go's thru the bend in the hose you feel a kind of snap in the hose. keep in mind that you need to make water go from one end of the pipe to the other and depending on the length of the zone loop it could take 2 or 3 minutes of full blast water thru the zone to move a air bubble. the air moves slower thru the pipe than the water does. when you think it's ok and no air shut the valves (drain and fill ) at the same time or fill slightly last to keep pressure in the system. if you don't have one in the system you should have one of these installed. it's known by the trade name AIR SCOOP. it's installed on the large pipe that the hot water from the boiler feeds to the zone or zones. it's installed just before the the pipes branch off to there zones. this air scoop will pick up air bubbles so small you won't here them running thru the pipe.
    this is the best residential air bleed.
  24. heating8

    heating8 Member

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    Excellent job with the photos.

    Just watch that as you're trying to fast fill that you keep an eye on the relief valve that's on the boiler. If it's piped down to within 6" of the floor, you're fine. If the water would do damage to anything around it, just keep an eye on it. Since this is new to you, you won't be quick enough to do it probably without the relief valve popping. One you start fast filling, the pressure will rise if you don't keep an eye on the pressure guage on the boiler.
  25. btuser

    btuser Minister of Fire

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    If he's got a monoflow system its going to be next to impossible to purge the individual radiators from downstairs. I think the problem he's having is one of the radiators is completely airbound. You may get it going again by purging from donwstairs but you're just re-introducing air that will eventually settle into this radiator again.

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