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(Yet Another) Single Pipe Balance Issue

Similar to another thread posted recently, I have a single pipe system with two mains. One runs along the front side of the house and the other runs along the rear side of the house (in the basement). The front main is pitched down from the boiler to the main vent and there is a wet return off of that. The rear is pitched up slightly from the boiler to the vent (after being flat for a stretch - 6 -8') and there is a wet return off of that as well. The rear side is really slow to heat (the thermostat is often satisfied before the rear heats) and the first floor radiators pant. Also, what seems really strange, is that the rear main seems to heat quickly to where the first radiator is teed from. After that it is much cooler for a long time. That first radiator off the rear main where the joint on the main gets hot is also slow to heat - which I really don't understand. There is no banging. Vents have been checked. I guess I'm down to two questions. Does the slightly rising pitch on the rear main cause a problem? Maybe the rear main has a lot of crap in it because the rear main is flat before the pitch rises?

Comments

  • acwagner
    acwagner Member Posts: 505
    Are you able to get the pitch directly off the pipe, or is it insulated?
    Burnham IN5PVNI Boiler, Single Pipe with 290 EDR
    18 Ounce per Square Inch Gauge
    Time Delay Relay in Series with Thermostat
    Operating Pressure 0.3-0.5 Ounce per Square Inch

  • ChrisJ
    ChrisJ Member Posts: 12,827
    What vents are being used?
    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
  • rexster
    rexster Member Posts: 11
    Pitch is off the pipe. Gorton #1 on both mains. Rear vent is new. It was replaced to fix this issue, which it didn't fix.
  • ChrisJ
    ChrisJ Member Posts: 12,827
    > @rexster said:
    > Pitch is off the pipe. Gorton #1 on both mains. Rear vent is new. It was replaced to fix this issue, which it didn't fix.

    We need far more information than this.
    Pipe sizes, lengths. Radiator sizes, run out size and lengths and radiator vents.
    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
  • rexster
    rexster Member Posts: 11
    Ok. I'll have to put that together. What do you think of the possibility of the rear main being partially blocked that slows down the steam?
  • acwagner
    acwagner Member Posts: 505
    Balancing is more complex than just the volume of air within the pipe. Fittings and different pipe sizes cause friction, which impedes flow to varying degrees.

    I have two mains. One is slightly shorter than the other. One has one Gorton #1 and the other has four Gorton #2s on it. That's what it took to get them balanced.

    Try taking the main vent off the problematic main and leaving the pipe open and see if you can get steam down it. If not, then something else is going on.
    Burnham IN5PVNI Boiler, Single Pipe with 290 EDR
    18 Ounce per Square Inch Gauge
    Time Delay Relay in Series with Thermostat
    Operating Pressure 0.3-0.5 Ounce per Square Inch

  • ChrisJ
    ChrisJ Member Posts: 12,827
    > @rexster said:
    > Ok. I'll have to put that together. What do you think of the possibility of the rear main being partially blocked that slows down the steam?


    No idea right now.
    I have two 2" mains. An 11' long one with a single Gorton 1 and a 29' one with five Gorton 1s.

    Most cases a single Gorton 1 isn't going to cut it in my opinion.
    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
  • Jamie Hall
    Jamie Hall Member Posts: 18,923
    I'd be very very suspicious of the pitch of the rear main. If it goes up from the boiler -- even slightly -- it's counterflow, and it needs much more pitch to drain properly. On the other hand, if it goes down -- or could be made to go down -- to that wet return, it needs less. But level or near level... problems.
    Br. Jamie, osb
    Building superintendent/caretaker, 7200 sq. ft. historic house museum with dependencies in New England
  • rexster
    rexster Member Posts: 11
    The rear main hasn't been touched since I've lived here. It looks like there may have been a wet return near where the rear main pitches up. I have no way of knowing. There is a nut screwed into the bottom of the rear main at that location.

    I'm going to get the rear main vent off and see if the main heats up. I think I've done this test before, but at this point I'm not sure so I'll have to check it out.

    If the pipe won't heat up all the way to the vent with the vent off (it heats up to about a 1/3 of the way now), then I'll have to look at the inside of the rear main (I guess), I don't know what else I could do. I have to find someone to work on this system, I've had a lot of problems finding someone.
  • Fred
    Fred Member Posts: 8,518
    If that main starts at the boiler pitching down and then somewhere along it, it starts to pitch up, there probably was and should be a drip there that drops into a wet return. Otherwise water will pool there and steam will condense before it get to the end of the main.
  • rexster
    rexster Member Posts: 11
    Thanks for all the insights.
  • Jamie Hall
    Jamie Hall Member Posts: 18,923
    edited November 2019
    Fred said:

    If that main starts at the boiler pitching down and then somewhere along it, it starts to pitch up, there probably was and should be a drip there that drops into a wet return. Otherwise water will pool there and steam will condense before it get to the end of the main.

    Not should be -- has to be. No choice in the matter.

    Br. Jamie, osb
    Building superintendent/caretaker, 7200 sq. ft. historic house museum with dependencies in New England