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Insufficient flow

BillAllen
BillAllen Member Posts: 103
Wondering if you can help. I have a baseboard hot water system where i have 1 zone 60 feet BB not that much bb at all but the 007 seems too small apparently. The BB leaves the boiler new boiler W/M GV90-4 just installed, travels 15 feet then turns up to the attic across attic 15 feet them drops down feeds 30 feet BB then goes back up to the attic then drops down to boiler again. So I have some head pressure. Turning the system on I get no flow from the circ that came with the GV90-4. Any insights? Could I need a bigger pump? I installed an air vent in attic got to be the head pressure.

Comments

  • Paul S_3
    Paul S_3 Member Posts: 1,261
    edited September 2016
    is the zone fully purged? 60 feet of BB a 007 should handle..is this 60 feet of 1/2 inch or 3/4 inch BB?....how long is the total loop? whats your boiler pressure? you say its a new boiler did this work before the new installation......do you have pics of the new boiler and piping surrounding?
    ASM Mechanical Company
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  • Zman
    Zman Member Posts: 7,569
    It would also be helpful to know how high the run in the attic is above the boiler and what the boiler pressure is running.

    You don't have to worry about the 007 overcoming the vertical head once the system is purged and set to the correct pressure.

    Setups like yours can be difficult to purge. If the pressure is too low, the air vent can become an air suction device..
    "If you can't explain it simply, you don't understand it well enough"
    Albert Einstein
  • Steamhead
    Steamhead Member Posts: 16,832
    Zman said:

    If the pressure is too low, the air vent can become an air suction device.

    Especially if you're not Pumping Away.
    All Steamed Up, Inc.
    Towson, MD, USA
    Steam, Vapor & Hot-Water Heating Specialists
    Oil & Gas Burner Service
    Consulting
  • Mad Dog_2
    Mad Dog_2 Member Posts: 6,920
    Sounds air bound. 007 more than enough. That's a lot of ups and downs. Mad Dog
  • hot_rod
    hot_rod Member Posts: 22,121
    Is it piped per the manufacturers drawings? Is this a new version of the GV, or an older model?
    Bob "hot rod" Rohr
    trainer for Caleffi NA
    Living the hydronic dream
  • Gordy
    Gordy Member Posts: 9,546
    I seem to recall another thread with a WM gv, and a flow issue.
  • BillAllen
    BillAllen Member Posts: 103
    Thanks for the feedback guys appreciate. To answer feedback the zone is NOT Bled. What is happening is when I try to purge (forgot to mention) I get constant bubbles/air/surge coming back. I think what is happening is the water is trying to prime but can't I think the water is traveling up the supply and then back feeding up the return reaching a point below the attic and just never purging or priming b/c it might be air locked. The pressure is 15PSI about 60 feet BB total length might be 90 feet including attic book says no more than 92 feet. I may install a purge in attic and not a automatic taco vent for fear of freezing. I think manual purge up in attic might be better than Auto vent????
    Going there noon to day to continue. Its a slab house not basement old boiler was in kitchen did not provide sufficient heat before either however the new owners were not clear on that sometimes they had heat sometimes they did not.

    Thanks for the feedback.
  • BillAllen
    BillAllen Member Posts: 103
    Additionally, the piping is typical 3/4". I've done many heating systems never had a problem purging however this one has the 2 loops going up approx 8 feet over head into the attic and like I said twice up twice down but I think the circ should be able to move the water once primed/purged. I suppose I could cap the relief valve and send street pressure up there (just to purge) then reset everything back to normal.
  • BillAllen
    BillAllen Member Posts: 103
    The Caleffi never used one always the standard Watts S1156F. Why not just plug the relief valve and max out the auto feeder with 30PSI?
  • hot_rod
    hot_rod Member Posts: 22,121
    BillAllen said:

    The Caleffi never used one always the standard Watts S1156F. Why not just plug the relief valve and max out the auto feeder with 30PSI?

    Unique to the Caleffi Autofill is the high flow. At 30 psi inlet pressure it flows over 5 gpm, regardless of the fill pressure you dial in.

    I would not plug the relief, it will still lift open even with the plug, and may not reseal after you unplug, try 27- 28 psi first.

    The highest point is 8 feet above the boiler? Should not need more than 12 psi to purge that if you have a good flow.





    Bob "hot rod" Rohr
    trainer for Caleffi NA
    Living the hydronic dream
  • hot_rod
    hot_rod Member Posts: 22,121
    Maybe I wasn't clear on that. Set the valve to 28 psi if you need to purge a stubborn system. The accurate gauge on the discharge assures you stay below relief valve lift.
    More flow at higher fill and the increased pressure squeezes the bubbles smaller when pressurized.

    Unless they have a fast fill, many brands drop to about 1/2 gpm at 12 psi setpoint.

    There is no fast fill function on the AutoFill, set it and forget it, no need to catch the fast fill before over-pressurzing.

    At 12 psi, 14 psi set, we still flow 2 gpm, plenty for 1/2 radiant loop by loop. flow rate.

    This comparison test is with 30 psi inlet pressure.
    Bob "hot rod" Rohr
    trainer for Caleffi NA
    Living the hydronic dream
  • SWEI
    SWEI Member Posts: 7,356
    Can you valve off the boiler?
  • BillAllen
    BillAllen Member Posts: 103
    I could valve it off but too much work to install BV's. Going to try to fast fill (actually I did) but S1156F was then set for 15psi afterwards. I could set auto feeder for 24psi without purge and then purge with more pressure. Going to job is 20 minutes. Thxz guys
  • BillAllen
    BillAllen Member Posts: 103
    If I can prime the loop up to the attic (8feet from floor) I think the S1156F will then purge...I hope.
  • hot_rod
    hot_rod Member Posts: 22,121
    Those high point air traps can be a bugger to get out, and keep out.

    IF you increase the fill pressure and leave it, you need to adjust the precharge in any diaphram type expansion tank.

    Increasing the pressure in the expansion tank, lowers the expansion capability, watch the pressure as the boiler heats to limit, if you end up running higher pressure.
    Bob "hot rod" Rohr
    trainer for Caleffi NA
    Living the hydronic dream
  • BillAllen
    BillAllen Member Posts: 103
    Oh ya. I just finished I got the zone purged in the attic by installing 2 tees with 2 1/2 BD to bleed once I bled in attic I was able to have circulation. Everything good now. Will return next week for inspection to check everything again. Thanks for that info about expansion tank. Understood. So yes increasing pressure will provide less expansion but more pressure in the system. Thanks man, thank you all probably be back!
  • hot_rod
    hot_rod Member Posts: 22,121
    Is this an existing system? If so ask the owner if this is a re-occurring problem at every start up. Has someone else worked on it? if so, consider plan B to fix it once and for all.


    Does it have a good micro bubble type air purger. Those do the best job of scrubbing tiny bubbles that end up combining into a air lock at high points over the summer or off cycles.
    Bob "hot rod" Rohr
    trainer for Caleffi NA
    Living the hydronic dream
    Solid_Fuel_Man
  • Solid_Fuel_Man
    Solid_Fuel_Man Member Posts: 2,646
    Microbubble purges are worth their weight in gold. I've solved many "chronic air problems" with them, and by pumping away.

    Taylor
    Serving Northern Maine HVAC & Controls. I burn wood, it smells good!