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capacity of 1 1/4 pipe to displace air in a radiator

misterheat
misterheat Member Posts: 156
Good morning all, recently i have added a radiator to the end of a run that feeds 3 radiators . The first 2 rads are fed by 1 1/2 pipe and after the second tee it reduces to 1 1/4 (why they did it this way is beyond me .Its very old piping ) The last radiator is big for a big room and it replaced a smaller one which was not quite heating the room properly . Since the change to the new bigger rad ,it is only heating the first 3 sections of the rad during the long calls for heat in the morning after a 3 degree set back . I m still under my sq ft (386) for my IN5 boiler . The new rad is 5 tube 25 high 16 sections its a big rad for a big big drafty room . Have i exceded my capacity to displace the air in this new rad ?? It has a heat timer vari valve open all the way on it . Because this is basically the end of the run (main ) . * This is a branch and not the official main . The main that runs directly off the boiler is 2 inch . I will get some pictures up soon to help .Thanks

Comments

  • Abracadabra
    Abracadabra Member Posts: 1,948
    It has nothing to do with "ability to displace air". All that was changed was the radiator? No changes to the runout ? Is that runout pitched correctly? Is the upfeed from the main to the runout branch piped using a 45 or a 90? Does that 1-1/4" to the last radiator feed anything else? That new radiator looks to be about 65sq.ft EDR if it's a column type and not a tube type. Is the 1-1/4" pipe a "main"? Is so, that's a problem. Mains shouldn't be less than 2". Pics will help.
    misterheat
  • KC_Jones
    KC_Jones Member Posts: 4,713
    Another thing to keep in mind with a bigger rad. A bigger rad has the capacity to heat more, but it won't heat more than the amount of steam getting to it. If you had say a 10 section rad there before and the first 3 sections got hot when the thermostat called for heat and you replace that with a 16 section rad it will still only heat the first 3 sections. This is with all things being equal, same vent same pipe etc. Also each pipe size has an EDR capacity it is capable of delivering. I suspect as was already eluded to the piping may not be adequate for what you are trying to do.
    2014 Weil Mclain EG-40
    EcoSteam ES-20 Advanced Boiler Control
    Boiler pictures updated 2/21/15
    misterheat
  • Abracadabra
    Abracadabra Member Posts: 1,948
    if the 1-1/4" is simply the runout and riser the EDR is limited to 55 sq.ft. EDR, if the riser isn't dripped, that's assuming the Deadmen piped and pitched it correctly and it's still pitched correctly. If it's not, then that capacity drops.
    misterheat
  • misterheat
    misterheat Member Posts: 156
    SO the pipes in question are the one that goes toward the back wall . the one with the drip pipe it goes around the corner . the first 2 rads are 1 1/2 than i included a picture of the 2nd rad tee and as u see reduces to 1 1/4 and then goes to the last rad. SO starting at the 1 1/4 tee it runs straight 7 feet 90s into 5 feet of 1/14 and then turns 90 up thru floor to valve
  • misterheat
    misterheat Member Posts: 156
    its a tube style rad .pitches look good.i guess its considered a main but it end in a radiator
  • ChrisJ
    ChrisJ Member Posts: 11,862
    We could use a picture or two of the new radiator showing it's valve and vent.

    Also, how was that boiler skimmed? I don't see a skim port?
    Single pipe quasi-vapor system. Typical operating pressure 0.14 - 0.43 oz. EcoSteam ES-20 Advanced Control for Residential Steam boilers. Rectorseal Steamaster water treatment
  • Danny Scully
    Danny Scully Member Posts: 1,329
    The radiator is actually 48 sqft. The runout to it should be 1-1/2, and the "main" itself should be 2", or dripped somehow. Hopefully we can accomplish heating this radiator with a better venting approach (for now).
  • ChrisJ
    ChrisJ Member Posts: 11,862
    edited March 2015
    I have a 60sqft radiator on a 1 1/4" runout and it works perfectly fine. I also have another 50sqft on a separate 1 1/4" runout that is around 10 feet long and it also works fine.

    Why should this specific one be 1 1/2" and not 1 1/4 for a 48sqft rad? Not able to get proper pitch?
    Single pipe quasi-vapor system. Typical operating pressure 0.14 - 0.43 oz. EcoSteam ES-20 Advanced Control for Residential Steam boilers. Rectorseal Steamaster water treatment
  • Danny Scully
    Danny Scully Member Posts: 1,329
    Any runout over 8 feet should be up sized. Im suggesting that on paper, it should be 1-1/2, but as you've exemplified, sometimes things can still work perfectly fine when they're wrong on paper. That's why our 1st approach will be venting.
  • ChrisJ
    ChrisJ Member Posts: 11,862

    Any runout over 8 feet should be up sized. Im suggesting that on paper, it should be 1-1/2, but as you've exemplified, sometimes things can still work perfectly fine when they're wrong on paper. That's why our 1st approach will be venting.

    Ah.
    I was remembering what Abracadabra had also mentioned, and that was TLAOSH stated 55sqft was the limit. I didn't realize that was only for up to 8 feet.

    One of mine is only 2 feet long, but the other is at least 10. It has good pitch and I keep my pressure really low so maybe that's why it works.
    Single pipe quasi-vapor system. Typical operating pressure 0.14 - 0.43 oz. EcoSteam ES-20 Advanced Control for Residential Steam boilers. Rectorseal Steamaster water treatment
  • Paul48
    Paul48 Member Posts: 4,470
    Try reducing the venting on the first 2 radiators.
  • EBEBRATT-Ed
    EBEBRATT-Ed Member Posts: 9,761
    Steam will take the path of least resistance, simple as that
  • Steamhead
    Steamhead Member Posts: 14,771
    In the picture "boiler3", does that horizontal pipe slope back toward the boiler, or the other way?
    All Steamed Up, Inc.
    Steam, Vapor & Hot-Water Heating Specialists
    Oil & Gas Burner Service
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  • Fred
    Fred Member Posts: 8,518
    Steamhead said:

    In the picture "boiler3", does that horizontal pipe slope back toward the boiler, or the other way?

    That's the pipe I suggested a couple months ago needed to be pitched. It's a return. He says it is pretty much level. I think he said he would address that when the weather breaks.