Rhode Island Adding fluid to GT Flow Center

Discussion in 'Maintenance and Troubleshooting' started by gorilla121, Nov 11, 2018.

  1. gorilla121

    gorilla121 New Member

    Hello. I believe I have a very small leak in the loop. I have a GT Flow center. Its supposed to be very easy to add fluid as it automatically removes any air in the system. Is it as simple as opening up the top cap and filling it with antifreeze/water? Not sure what the steps are as its one of the few things you can't look up on youtube.
     
  2. docjenser

    docjenser Well-Known Member Industry Professional Forum Leader

    Yep, just unscrew the cap and add some water.

    It is possible that some air has been purged out, not every drop is a leak.
     
  3. gorilla121

    gorilla121 New Member

    After 6 years of trouble free service the unit just stopped working. Called someone out to service it and they told me the fluid was low. Since the entire system is closed either the pipes expanded or you have to assume a leak right? If its really as easy as unscrewing the cap and filling it i'm not too worried. I would need to shut the system down first right? And thank you so much for your help!
     
    Last edited: Nov 13, 2018
  4. urthbuoy

    urthbuoy Well-Known Member Industry Professional Forum Leader

    If they diagnosed the system as low without just adding some fluid themselves, I'd be suspect on their experience. They may have measured the low pressure on a non-pressurized system and come up with that diagnosis?
     
  5. gorilla121

    gorilla121 New Member

    No they purged the system and added more fluid. Although im not sure why a purge would be necessary with the gt flow center. I was just interested in checking the levels and keeping the unit operational. Once it shuts down I end up needing to call the guys in and takes a few days. Kind of a pain.
     
  6. nc73

    nc73 Member

    If it's a flowcenter why aren't you checking the level yourself?
     
  7. gorilla121

    gorilla121 New Member

    The unit doesnt have any instructional manuals and I didnt even know the cap on top was something that could be removed. But sounds pretty basic. Whats the fluid that needs to be added? Straight water? Distilled water? Propelyne glycol? Im worried that when I open the cap that liquid will just gush out. Ill tell you how it goes.
     
  8. nc73

    nc73 Member

    Twist the cap off slowly. If you see the water level change when the unit shuts on or off, more than a half inch i think, there is air in the loops. If you smell methanol than it's obviously a methanol mix (20%). Not sure how to identify the other possibilities.
     
  9. gorilla121

    gorilla121 New Member

    They left a bottle of boiler fluid so i'm assuming it's a propelyne glycol mix. I guess I can use my radiator fluid gauge to check the mix. Sounds like the cap can be opened while the unit is still operating?
     
  10. nc73

    nc73 Member

    Yeah you can open it while it's operating.
     
  11. gorilla121

    gorilla121 New Member

    Is there a line that says "fill to here" or do you just eye it? Thank you for the help!
     
  12. nc73

    nc73 Member

    Yeah there will be a line, might be hard to see.
     
  13. Jamesck

    Jamesck Member

    Great topic and I am glad I found you. I think I am in a similar situation on loop pressure. This system has been in operation now for almost 9 years. I have not checked the pressure on the loop in 5-6 years. I can hear a very slight noise coming from the flow center while it’s running and suspect it’s low. I wish I had the reservoir style set up with the removable cap now, but at least I have a juicer set up for a garden hose. This system has methanol in it too and this is all new to me...hint hint.
     
  14. docjenser

    docjenser Well-Known Member Industry Professional Forum Leader

    You can just use tab water, adding a gallon is not going to make much difference to the antifreeze concentration. On top there is an elbow where the fluid comes into the flow center, as a rule we fill it to about 2" above the top of the elbow. Depending on the loop, fluid volume and kind of pipe used, you see a 1/2 - 1" drop in fluid when the pump turns on. If you see more drop, or rise when the system shuts off), there is a likelihood that there is air in.

    Air (or gases) in the system is not unusual after a few years of operation, after all H2O is made up by 2 gases (hydrogen and oxygen). That is why none pressurized flow centers were invented, since gases dissolved in the water can participate out over time.

    The cap is not air tight, so you can unscrew it with out water gushing out.
     
    Jamesck likes this.
  15. Jamesck

    Jamesck Member

    Thanks for the response. I don’t have a reservoir style flow center though and will need to just feed in tap water with the needle valve. I assume I put it into the intake port on the unit until I reach 20-25 PSI. The flow center used to be totally quiet and I am barely starting to hear noise now, which makes me believe it’s low pressure. Could I just tap on to the ball valve on the bottom of the water heater, or should I use another tap for my source?
     

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