GEO Testing kit

Discussion in 'Maintenance and Troubleshooting' started by GoHuskers, Feb 14, 2014.

  1. GoHuskers

    GoHuskers New Member

    Hello all,

    I want to have a testing kit so I can test my unit WITHOUT calling the tech over. I saw they use a pointy pressure gauge and thermometer and pushed it through the P/T plugs to test the water temp and pressure. They also test the Air supply and air return temps.

    Is there something I can buy for novice use (name/brand/Sold on Amazon)? Not to expensive as the pro use.

  2. josephparris

    josephparris Member

  3. AMI Contracting

    AMI Contracting A nice Van Morrison song Industry Professional Forum Leader

    just a thermometer tells you a lot about your geo performance. You also want a pressure gauge. which can be as simple as a gauge attached to a basketball inflation needle.
  4. GoHuskers

    GoHuskers New Member

  5. Palace GeoThermal

    Palace GeoThermal Well-Known Member Industry Professional Forum Leader

  6. mtrentw

    mtrentw Active Member Industry Professional Forum Leader

    Palace GeoThermal likes this.
  7. dgbair

    dgbair Just a hobby Forum Leader

  8. tommytx

    tommytx Member

    GoHuskers.. did you order and find any of these perfect for what you need.. I am a non pro and would love to have the pt pressure and temp gages and like you dont want to spend 2-300 bucks.. but 75 or 80 would be ok.... any experince you had with this order would be appreciated.
  9. arkie6

    arkie6 Active Member Forum Leader

    You can find pre-made geothermal test port pressure gauges on ebay for around $35. Search for [geothermal test port gauge]. For temperature all you need is a digital meat thermometer with the small diameter probe. You can find these on ebay or at Wal-Mart or Amazon for less than $20.
  10. Jonas Baltrusaitis

    Jonas Baltrusaitis New Member

    I was just wondering (if the post is still active) how to measure the delta T between the ground loop in my Geothermal unit. I am afraid that once I stick something into those PT ports, everything will start leaking. Can anybody suggest how to safely do that and perhaps a digital thermometer that would somehow transmit into the computer or record the values? I am also planning to measure delta T in my attic unit for the internal loop and I can;t climb there to monitor every time. Thank you in advance
    I had the unit recently installed and I want to do the reality check that it works properly
  11. tommytx

    tommytx Member

    Hey don't worry about it leaking.. its made for that... delta T is fine for ballpark but for setting the water flow most mfgrs do it via the pressure drop across PT1 and PT2..
  12. Jonas Baltrusaitis

    Jonas Baltrusaitis New Member

    Stupid question: is it possible to measure both? PT2 and PT1 are ports on the downstairs unit for the external loop?
  13. tommytx

    tommytx Member

    Not only can you read both PT1 and PT2 but its required that you do so.. There is two trains of thought I is to be looking good and buy two sets of gages.. one for PT1 and one for PT2... so you can read the difference between them more easily... however these will not be precision gages and that means that its possible that one gage may be off by one psi high and one could be off by 1 psi low... so when they read with 2 gages a 2 psi diff would show as zero.. since one is in error one way and the other the other way and worse if they are off by 1 psi the same way then a true 2 psi differential would actually show as 4psi.. so instead of reading 2 psi different it would actually show 4 psi difference.. Make sense.. so the smart guys will read on port and write it down.. then read the other port and subtract them for the difference.. that way if they are not perfectly calibrated (and they won't be) you will be 100% accurate... no matte what the gage error is...
    For example if you had a damaged gage and instead of reading 0 when no pressure it might read 10psi for Zero.. matters not the difference will still be accurate since both readings are in error by 10 the difference is right on.... 12 Psi on PT1.. and 14 psi on PT2 = diff of 2 psi which will on the chart equate to maybe 6 GPM. Again do not try to use Delta T to set flow.. its a quick check but highly inaccurate and when you see the tech do that kick him in the but and say "Can you show me that Delta T is approved for flow setting in the manual." most mfgrs say NEVER do that.. only the Press diff between pt1 and pt2 can be used.
    Ok.. where should you see the highest pressure PT1, or PT2? Well let't think about what we are doing.. measurning the pressure drop across the cooling coil.. and normaly PT1 is inlet water and PT2 is outlet water.. So PT2 should be the lowest.. Like PT1=14 and PT2=12 so see my error above.. where it says PT1 says 12 which can never be true unless the water is running thru backwards.. So PT1 ON INLET will never be the lowest.. but read carefully.. trust me if your gage is very hard to read 2 psi accurately on a 100 psi gage..
  14. Jonas Baltrusaitis

    Jonas Baltrusaitis New Member

    Very useful. I am actually trying to find tridicator gauges and connect them to PT port via valve. Now if only there were lower T tridicator gauges since most I find start at 70 F
  15. wing

    wing Member

    In my new build install, I included 1/2 or 1/4 inch ports to accommodate temperature and pressure monitoring on both sides of the supply and load loops. Two ports per each side, 8 total. Ports are most easily accommodated at elbow junctions although other configurations are possible.

    Four ports for temperature sensors. I am using a ProSense temperature probe with 4 to 20 mA analog output.


    Four ports to connect a differential pressure sensor (pseudo flow meter based on pressure drop across the heat pump supply and load). Connection is via 1/4 inch flexible copper tubing). Output from the sensor is 4 to 20 mA analog current.


    The six sensors (four temperatures plus two differential pressures) report to an analog input module, in my case the ControlByWeb X 418. This will allow remote monitoring of the heat pump and performance logging. As the X 418 allows a total of eight analog inputs, I also added current sensors to the heat pump power input and my hot water heater backup.


    It is possible to pick up sensors on the cheap from E bay.

    Key point is that it is infinitely easier to provide ports for temperature and pressure monitoring in the installation phase rather than adding them later and going through the hassle of draining , filling and flushing the supply and load loops.

    Good luck with your geo journey.

    Attached Files:

  16. Jonas Baltrusaitis

    Jonas Baltrusaitis New Member

    Dear all, since I am on this post already, I ordered P and T gauges for my external loop. However, one thing bothers me in the current setup. Once it kicks in for heating, temperature drops. I can monitor it with my ecobee, see below. Anybody has any suggestions why this might be happening? It is with the stage 2 heating fully running.
  17. ChrisJ

    ChrisJ Active Member Forum Leader

    I'm guessing it has to do with the location of the thermostat relative to the return air intake. The cooler air is drawn to the return grill passing the thermostat, takes a while for the warm air from the supply ducts to reach the tstat.

    I would not want my heat pump always going to stage 2 every time heat is called for. You may have to increase the number of degrees of drop before the stage 2 kicks in. For example it looks like at 3 degrees below set point it stages up from stage 1 to stage 2, if you increase that difference to 4 degrees it may let stage 1 run longer to satisfy the call for heat.
  18. Jonas Baltrusaitis

    Jonas Baltrusaitis New Member

    Yes, this stage 2 running continuously has been my headache for a while. While I am about to monitor loop temps, here are my controller settings. Please let me know what you think:

    Heat/Cool min delta 5F
    Aux Heat Max Outdoor 10F
    Compressor min Cycle off time 300 seconds
    Heat Differential Temperature 1F
    Aux min on time 5 min
    Compressor min on time 5 min
    Compressor stage 2 temperature delta 3F
    Compressor stage 1 max runtime 20 min
    Compressor to Aux temperature delta 4F
    Compressor to Aux runtime 90 min
  19. SShaw

    SShaw Active Member Forum Leader

    "Compressor stage 1 max runtime 20 min" -- could defeat the purpose of having a 2-stage heat pump by forcing second stage when it's not needed. It's better to have the thermostat control staging based on inside temperature rather than run time.

    "Compressor to Aux runtime 90 min" -- same issue. This setting could cause AUX to kick on when not needed. Your setting of "Compressor to Aux temperature delta 4F" will turn on AUX when the inside temp drops 4 deg below the set point, so the time setting is not needed.

    Based on the image you posted above, something doesn't look right with your overall system. It looks like your heat pump runs on stage 2 for four hours straight just to keep the set point at 62 degrees. A temp of 70 would be a more typical design temp that the system should be able to maintain if properly sized. That would indicate either the unit is undersized or there is a problem with the heat pump, or ductwork.

Share This Page