No second stage in cooling????

Discussion in 'Maintenance and Troubleshooting' started by sixmenn, Jul 21, 2011.

  1. sixmenn

    sixmenn New Member

    I have a HeatController GeoMax 2 2-stage system ( model # HTV048A1C01JRK) with a honeywell TH6220D1002 thermostat. I have an open loop system.

    In the winter, it will run on 1st stage and 2nd stage as needed to supply the heat. I was expecting it to do the same this summer. However, we are in the middle of a humid week of temps in the 90's, and the best it can do is get it down to 78 degrees. It only ever runs on the first stage. I've tried lowering the thermostat to see if it will kick on the 2nd stage, but it won't come on. My Y2 is never lit, if that means anything to anyone.

    On another note (maybe related to the above problem???) is that my HWG doesn't seem to produce any hot water. Once in a while I'll find that the HW-out is a little warm, but most of the time it is just room temperature. At any rate, it's never hotter than the HW-in.

    The only thing I can think of is that maybe my thermostat isn't capable of 2 stage cooling. Any ideas?

    Attached is the owner's manual, if that will help.

    Many thanks to anyone who can help!

  2. Jamesck

    Jamesck Member

    2nd Stage

    Your thermostat may need to be adjusted. That model appears to be capable of two stage cooling, so you should be able to change the settings. If it is already set up right, double check your wiring.
  3. sixmenn

    sixmenn New Member

    How would I adjust it?

    Any thoughts on the HWG problem. Do you think it's related?
  4. tstolze

    tstolze Member

    You need the manual for your thermostat, if you don't have it I am sure you can find it online. If you are not comfortable following the manual, call your preferred A/C service person. You may have them check the desuperheater also, I would first worry about 2nd stage not working. My desuperheater inlet/outlet typically run .8-2 degrees difference.
  5. sixmenn

    sixmenn New Member

    Thanks. I think I do have the manual somewhere in the pile of stuff that came with the house. I'll give it a shot tomorrow.

    Thanks for the answer regarding the HWG. Does yours feel hot to the touch, though? What is a typical temperature for the inlet and outlet?
  6. geome

    geome Member Forum Leader

    I could be mistaken, but this does not appear to be the correct thermostat for your 2-stage system. Near as I can tell, the TH6220 can only run 2 stage cooling with a conventional system. Your thermostat should be set up for a Heat Pump. The TH6220 is only capable of 2H/1C in Heat Pump Mode.

    The TH6320can be set up for 2-stage cooling, not that I am recommending this for your system. It's in the same manual, that's why I'm mentioning it. Here is a link:

    I wouldn't be surprised if in heating mode your system never went into second stage either. It may have been going directly from first stage to aux heat. Not good, if this is really what happened, since it will cost you more if you have electric resistance heat installed.

    P.S. If this is the case, at most, I think you should get charged only for the incremental cost between the thermostats, and not for the service call or installation. The thermostat should have been fully compatible with your 2-stage system from the beginning. I might even nicely suggest that the installer eat the price difference since you may have paid more for aux heat than necessary since your stage-2 heat never engaged. Stay friends with your installer though. :)
    Last edited: Jul 22, 2011
  7. tstolze

    tstolze Member

    The temperature of the outlets vary on hot water usage, if we all take showers the buffer tank along with the piping is near the temperature of the incoming water. After a cold day and night it may be 125°.
  8. sixmenn

    sixmenn New Member

    You are totally correct, Geome. I found my manual today and discovered the very things you mention. I started looking around online for TH6320D thermostats when I had a thought: "All this $140 thermostat is going to do for me is call for the second stage cooling by sending a signal to Y2. Heck, for the 5 days a summer that my geothermal doesn't keep up and I need the second stage, I'll just wire in a switch and flip it to activate Y2 when I need to."

    I tried it today and it seems to work. Y2 lights up, the second valve opens up shortly after, and I hear a change in the sound of the compressor. Is this reasonable, or am I committing an HVAC faux-pas?

    Incidentally, I don't have the electric AUX heat, so no worries there. I do think that's how my system is wired, though: AUX shows up on my thermostat when it calls for second stage heat.
  9. sixmenn

    sixmenn New Member

    My HW-out seems to vary between room temperature (most of the time) up to warm-to-the-touch (this is what it's doing today with the cooling mode on pretty much constantly). It's never hot. Does this indicate there's a problem with it? If so, what should I check first? I've made sure there is power at the terminal that feeds the HWG pump.
  10. sixmenn

    sixmenn New Member

    I know this thread is cold, but I thought I'd update it for anyone who may have the same problem.

    Apparently whoever installed the system put a check valve in the DSH's water loop, but then piped it so that the flow ran against the check valve. Essentially it was never able to flow water. Once I reversed the in and out lines, it works great.
  11. Mark Custis

    Mark Custis Not soon. Industry Professional Forum Leader

    Thanks for the update. I think I speak for all here that try and help out with problem systems we like to hear when things get fixed. There are lots of posts that I typed to trying to solve problems just go away never to say if the help here fixed the issue.


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