Colorado replacing old circ pump - need input

Discussion in 'Maintenance and Troubleshooting' started by JD B, Aug 1, 2019.

  1. waterpirate

    waterpirate Well-Known Member Industry Professional Forum Leader

    Doc could chime in on the dollars as he is a pump design guy to the max. Your system uses 1 26-99 correct? 1 pump running wide open is better than throttling 1 pump to meet specific unit parameters. Early in my life I used to install full port brass throttling valves that no one seemed to care were there, so I stopped. I do my homework on the loop design and try to install as little pumping as needed ( thanx Doc ) and let the rest take care of itself. fluid injection is a non starter for np flow center. Pt ports should be on the unit ideally to measure what the coil is doing, not the flow center.
  2. JD B

    JD B Member

    Good to know - so many big ticket items burned out in the last month, I'm seeing the boogeywoman everywhere. Yes - UP26-99. System was clearly a quality install that's been trouble free forever. So if no worries on chunks in fluid side of evaporator - a flush and new NP flo center should get the old HP online. Compressor and RV new in 2012 and with NP flo center and flush that leaves only the coil - blower - evaporator left of old system. Given age of the blower motor - does a preemptive replacement with an ECM motor make sense? Even if the blower could go another decade or so - are the ECM fan motors energy efficient enough to make the jump prior to failure?
    Noticed I mentioned loop fluid running through the guys are pretty nice to overlook that!
  3. JD B

    JD B Member

    Have not heard back from the Geo folks on installing NP flow and purging loop yet. But the temps to pass the 100s so I'm going to get the old flow center and new pump on line until they are here. Going to put all your advice to work before I croak in the heat.
    Eric - knowing that full out pump pressure from non functioning isolation valves is not a huge problem, will install new UP26-99 and use the fill tool to pressure up the loop after purging air from flow center and pump. Will attach new pump to defective valves and call it good.
    As I intend to get the NP flow and have loop purged/filled with new water/antifreeze - will not worry about using my less than perfect well water for the purge and pressurizing of new pump install. Actually, if age has caused the antifreeze to become acidic - a little of my alkaline water may be a good thing in the short-term.
    waterpirate likes this.
  4. JD B

    JD B Member

    Pump installed and temp from register at the mid 50s. Just in time for the 100 + heat here to keep me alive until new flow center is installed. The Geo gooser is a pretty nifty item - thanks everyone for that tip. Sorry for pushing the edge of needy on my questions - my shop is a 100 yards from the house. Between the basement stairs and the 100 yards - tips to save steps were essential. Never appreciated how great having a go-fer was. I may have a problem with the install of the new flo center that I will put onto a new thread.
  5. waterpirate

    waterpirate Well-Known Member Industry Professional Forum Leader

    I am glad a plan is coming together for you! A solution is always there, some times it is just hiding behind other issues. Keep us posted, we are here to help :)
  6. JD B

    JD B Member

    Thank you all for the help and patience. Regrettable - may have jumped from pan into fire on the non-pressurized flow center.
  7. waterpirate

    waterpirate Well-Known Member Industry Professional Forum Leader

    How so?
  8. JD B

    JD B Member

    New non-pressurized flow center installed but they didn't show up with flush cart, rinky-dink check of antifreeze % and no numbers of flow rate done just set 3 speed pump on high and left. Visible chunks began to collect on bottom of tank after a day. Not why I paid out of state for geo-experts 4 grand to install. I assume the growing volume of gravel, in the flow tank, is washing out of the loop.

    When checking tank level today (unit off) thought the fluid radiating warm. Checked - tank temp was 84 and residual fluid at out Pete's 86.3. Ambient temp of basement mid 60s. Turned unit on and checked later. Tank fluid temp was hovering mid 90s and pump housing temp over 100. So I shut down.

    Outside temp 104 but nights cool to 60s and loops 6' down. HP was keeping the house cool but the temp of incoming loop fluid being that hot scared me. Summer, the fluid is supposed to dump heat gather cool and return to the flow center - right? Only thing I could think of was antifreeze % below the 15-20% level. Do I have trouble?
  9. waterpirate

    waterpirate Well-Known Member Industry Professional Forum Leader

    The good news first.
    Collecting the gravel and debris in the bottom of your np tank keeps it out of your pump. clean tank bottom as needed.
    It is nearing the end of the cooling season, loops should recover.
    Because you have a np flow center now you can do your own adjustments without worry about fluid loss.
    Measure the flow rate through your PT ports using a pressure gauge and compare to unit chart to verify flow rates.
    Turn pump down 1 speed and check again and compare with data from high speed
    hope this helps
  10. JD B

    JD B Member

    Eric - it helped more than I can say. The n-p unit's purchase was intended as preventative maintenance for the aging system. The $ spent is about a third of my retirement income, a reasonable investment IF it works. There lies my concern. Could the compressor (7 years old) or orig. TXV be failing?

    Flow rate Pete 1 = 12 psi /Pete 2 = 5psi for a 7 psi drop. The specs for the unit state the waterflow rate (gpm) as 6.3 and the pressure drop (psi/ft. H2O) as 4.4/10.1 BUT no unit chart related to flow rates. Using the GeoFlo flow rate calculator (Polyproplene @20% and nominal flow rate 6.3 and their chart for nominal pressure rate of 1.9 psi) their calculator with the 7 psi drop gives a flow rate of 12.1 gpm. BUT the highest EWT was only 50 degrees.

    I'll do the next lowest speed tomorrow and see if any of makes sense to me. What change should I be looking for?

    Reviewing orig. install, it shows the glycol @ 20% but doesn't show the use of any inhibitor. Does it make sense to consider adding a quart of Fernox F1 inhibitor at this point? My calculations of loop is it has 78 gallons of fluid in it.
  11. JD B

    JD B Member

    Eric - you've been wonderfully patient sticking with me in my circ. pump quest. The loop temp rise signifies a recent change in the system. 10 degree jump in a couple days and a large jump from July. Nearly same temp in as out. I interpret sudden changes, in mechanical units, as stress created by other linked components weakening or failed. Or caused by incorrect settings. While the high temp may be within operating tolerances, as are very low winter temps, its a recent change. BUT - the system is cooling great. Maybe the ole HP is having hot flashes.
  12. mtrentw

    mtrentw Active Member Industry Professional Forum Leader

    Natural ground temperature at 6 foot depth will typically peak in the first weeks of August (this will vary by location).
    Even though loop wasn't as hot in July, you've been constantly adding to the natural curve above, so there is less ability to reject heat, so it may be possible that mid-90's is not unusual. It is also possible that you introduced an air bubble during pump changes which may be taking a portion of your loop field out of play.

    On another note, antifreeze/coolant is a less efficient heat transfer medium than pure water, so lower glycol wouldn't be a problem for heat transfer. It is really only there for freeze and/or corrosion protection.

    I saw another suggestion to lower pump speed. Obviously good advice to monitor flow and find lowest speed for required water flow, but I might consider keeping pump at higher speed for a while to better flush stuff/debris/entrained air through the system.
    waterpirate likes this.
  13. Comity

    Comity New Member

    JD, just wanted to check and see if your loop temps settled down and if your unit is cooling okay. My system is 26 years old and still running. It is a 4 ton 2 speed Waterfurnace with 4 vertical 200’ loops pressurized and running 2 26-99 grundfos pumps. Over the years I have had to replace multiple pumps because of the loop not being flushed properly in the beginning. Small flakes of black material was actually wearing holes through the cast iron volutes of the pumps! Of course it took me years to finally figure that out. So I have flushed my loop multiple times using a hose hooked up to my flow center. On the outlet side of the loop I installed a valve and pressure gauge and adjust the pressure as needed to maintain a good flow rate and not have too high of loop pressure. Being that we have almost a 100# of water pressure I was able to flush a ton of crud out of the loop. It also flushed any air out of the loop when I kept back pressure on the loop. As far as water from your farm, if you have high alkaline water, you can purchase a pool test kit to test your water and add a small amount of Muriatic acid or dry acid to the loop to balance the alkalinity. Getting all the air out of your loop is very important to make your system work properly. There are no geothermal dealers in my area so I have had to learn geo by the school of hard knocks. Currently I am dealing with a lower delta air temp even after I had my ac guy recover the r22, pull a vacuum, and refill with virgin r22 weighed in . I think I have a bad txv, but having ac guy come back to see what he thinks. About 20% of the evap coil is not sweating and is 10 degrees warmer than the rest of the coil. Txv is also hunting constantly.

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