South Carolina Correct Valve for FHP

Discussion in 'Maintenance and Troubleshooting' started by avidphotog, Jan 4, 2016.

  1. avidphotog

    avidphotog New Member

    Hello all.

    Let me preface all of this by saying that I am a layman and I know very little about plumbing, let alone heat pumps. As I result, I will need both your help and your patience.

    I bought a home that has three heating units, one (2-ton) Trane heat pump, and two Florida Heat Pump (FHP) Geothermal systems. I have one 1/2 HP well (with a new pump) that serves both FHP units, and just last week I installed a second well in order to return the water back to the aquifer. The FHP’s were installed at least a decade before I purchased the house, and were most likely installed by the homeowner himself. That is to say that he did not follow protocol with the installation (likewise for the many other electrical and plumbing messes that I’ve been left to clean up). In any event, here is what brings me to the forum:

    The installer used irrigation valves to control the water flow to the two FHP units. His configuration does not make any sense to me. Water enters one valve, and then enters two valves in parallel, and finally returns to a single line before it enters the FHP unit. Here's a photo:

    IMG_4710.JPG

    There are at least 3 problems with this set up:

    1. One valve is leaking and now needs to be replaced.

    2. I was told by at least one HVAC repair guy that the valve(s) should be on pvc pipes that leave the unit, not the ones that enter. Having it set up as he recommends would allow for water to always be in the system. As it is currently configured, the system is dry between cycles. So the first question is, is this correct? Do the valves need to be switched to the other side?

    3. Given the current set up, I have no way of controlling the water flow (gpm) into either of the FHP units. Judging from the amount of water I see going down my return well, my guess is that all of the valves are wide open. The units are certainly getting the water they need, but I’d bet it’s two or three times the required amount (which, I guess I also need to find out what the required amounts are). I was told that having such a large volume of water pass through will shorten the life of my pump (as it will run constantly) as well as shorten the life of the FHP systems themselves (true? false?). Someone mentioned something about a Taco valve to me in passing, but I didn't / don't know enough to make use of the information given.

    So… my question in a nutshell is, what do I have to do to get this system properly set up? I have called Bosch (now owners of the FHP brand) but there is not a “certified technician” within 80 miles of my home, and the local HVAC guys have not given me much confidence in their understanding of geothermal systems (their simple suggestion is to rip it out and put a standard heat pump in).

    I am finally ready to go the DIY route, or at least gain enough knowledge to direct a licensed technician to do the work for me. Your help is greatly appreciated.

    Thanks for your time.

    Split unit: Serial #GJ000960D, FHP Model EM024-1CSN
    Package unit: Serial #AA048160, FHP Model HE027-1HZN

    FullSizeRender (1).jpg FullSizeRender.jpg
     
  2. geoxne

    geoxne Active Member Forum Leader

    1. My opinion - replace the whole mess. There is no telling what the original installers idea was. One guess is he was trying to reduce water noise by spreading water flow out to multiple valves. If you had 2 stage equipment than 2 flow rates and 2 valves would make sense.

    2. Yes

    3. The existing "irrigation" valves have a throttle (3 pointed knob) for flow control. An irrigation valve is a decent low cost alternative at 20 or 30 bucks and are readily available. They open quickly and close slowly to help relieve water hammer. Taco has a orange headed geothermal valve that is 7 to 10 times more and in my experience are no more dependable. Taco's latest is the Zone Sentry which has proven very dependable for me over the last 6 years at a price some where around 100+. Your choice.
    Flow is very important in an open loop system. Overflowing will not only put more wear on the coil but also you whole pumping system. Even in a well controlled system cost of pumping can be 15% to 25% of the total cost of running the geo open loop system. Flowing more is just a waste of $. I strongly recommend an automatic flow control valve such as a Hays 2305 MeasurFlo or similar. The rule of thumb for open loop is 1.5GPM per ton with entering water >50F. Here is a diagram to help.
    OpenLoopPipe.JPG
     
  3. avidphotog

    avidphotog New Member

    geoxne,

    Thank you for taking the time to respond so thoroughly. Much appreciated. I do plan to remove all of the irrigation values on both systems. Based on your confirmation, I will also move the replacement valve to the "Water Out" side, as shown in the image you provided. The image also highlighted something else I don't have (boiler drains)... so I'll have to think about that as well. Finally, I do have one follow-up question: You mentioned both the Hays 2305 MeasurFlo and the Taco Zone Sentry valve. Do those do the same thing? Is one better than the other? The Taco valve was easy for me to find (and potentially purchase) online. The Hays... not so much.

    Thanks again for your help.
     
  4. geoxne

    geoxne Active Member Forum Leader

    No.

    The Hayes 2305 is the "flow regulator" in the diagram. They are available with different fixed flow rates in 1 gpm increments. I believe one 3GPM model for each of your HPs will provide the correct flow rate for South Carolina.
    http://flowcontrolvalves.haysfluidc...s/series-2305-mesurflo-automatic-flow-control

    The Taco Zone Sentry is a "water solenoid control valve" in the diagram. It will be wired to the HP to open when the compressor is running. As I said previously a commonly available irrigation valve is a decent alternative
    http://www.taco-hvac.com/uploads/FileLibrary/100-82.pdf

    Make sure you have the "shut off valves" on each HP to isolate when any future work is done on the individual lines. Also, this "shut off valve" on the water out line of each HP can be partially closed to a balancing point where water noise will almost disappear (remove the handle when you find the sweet spot). At 3 GPM I use 1/2" pex for lines to the HPs and 3/4" main manifold would be sufficient for an open loop system at typical pressures with 2- 2ton HPs.
     
  5. geoxne

    geoxne Active Member Forum Leader

  6. avidphotog

    avidphotog New Member

    Got it. Thanks again for taking the time to explain it to me. I think I'm well on my way.
     
  7. Larre5

    Larre5 New Member

    I know this is an old post, but just thought I'd mention that FHP once recommended that setup, with one valve adjusted for heating, and another adjusted for cooling, with each tied to the appropriate hot wire for that operation. The idea was that heating took less gpm than cooling. I ran a DIY slightly undersized used FHP 3 ton for over 15 years before upgrading to a new 4 ton climatemaster. I use a single taco geothermal valve with a flow restrictor made from pvc fittings and a brass nozzle to reduce the flow to about 12 gpm max, and a ball valve to trim it to about 10 gpm. I added a dual temp digital temp sensor and wrapped the thermocouples to the inlet and outlet that reads both temps, and tune the system for about a 10 to 12 degree change. I highly recommend the zone temperature monitor, as it helps detect low flow problems. Taco Geo valves are great, but expensive.
     
  8. geoxne

    geoxne Active Member Forum Leader

    This may be true in a cooling dominant climate with elevated source water temperatures. However, the opposite is true in a heating dominant climate with typically lower source water temperatures.

    Thanks for that info about the FHP recommended setup from the past. I did not know, but we should make it clear, that recommendation would be geographically specific.
     
  9. docjenser

    docjenser Well-Known Member Industry Professional Forum Leader

    And that setup should only be used for open system. Flow restrictors are a no-no in closed systems. Why would you waste the energy to increase the pumping power only to limit the flow.
    And if you are in south Carolina, your ground temp in an open system would be in the low 60sF, where you need even lesser amount of flow. Your 2.5 gpm, with your new CM 4 ton unit would also waisting pumping power.
     

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