So twice this winter, I have experienced what I would consider a run away situation. Came home today from work, thermostat said 65 degrees. Wife was cooking in the kitchen. Checked the air temp with a kitchen thermometer, read 74.9 degrees. Shut the unit down, power cycled the unit, thermostat showed 74 deg on reboot. No way the temp raise 10 degrees in a min. Any ideas or explanation? Note: it got up to 70 deg outside today.
I haven't seen that before. The only thing that comes to mind would be a communications problem between the thermostat and the unit, due to either a loose or bad wire, or electrical interference. You could check the wiring on both ends to make sure it's screwed down tight. Is the thermostat wiring 18 GA or larger? Is the wiring kept away from any high voltage wiring? If interference were the problem, you could try connecting the thermostat using shielded twisted pair cabling.
I suspect it is larger gauge wire. Original thermostat wire from 1978. Not sure if there is any high voltage wires near it. I could easily run cat 6 if that would work. Just odd. The unit has been fine for the last 5 years.
That is odd. It could be a failing thermostat too. Cat 6 should work, provided it's a shielded version of cat 6. From one of the thermostat manuals: "Use 4-conductor 18 or 20 AWG thermostat wire unless issues with EMI are anticipated. In that situation, use 24 AWG shielded twisted pair cable grounded to “C” terminal on the relay board end." No further details are provided, but I would connect the cable shield to C on the unit side and leave the shield disconnected at the thermostat side. I would put +/- on one twisted pair and R/C on another pair.
To follow up with this, the unit did not run all night. House temp was 70 deg when I woke up at 5. Set point was 68. 0 usage on symphony.
Based on your screenshot, you were in Heat mode with a set point of 68. If it was 70 inside, the system would stay off in Heat mode. You should check the thermostat error log to see if any errors were logged by the system. I would think it would log an error if the thermostat lost connection.
Talked to my tech today. He has had a few t-stats flake out like this. Of course it is 6 months out of warranty.. He wasn't sure of the exact price but 200-300$.
I have Intellizone2 zoning and the master thermostat has a history of the last 10 fault codes. I believe it's under the installer settings menu. Yours might be different. You might need to use an AID tool to read the fault history from the heat pump unit.
Is software ver 3.0 the latest version for the CC-U01? The tsat did it again. Heard woke up to the unit sounding like a jet turbine. Checked symphony on my phone. Heat stage 11 and was reading 66 deg. Baby monitor showed 75 deg. Tstat was set at 71. Went and pull the tstat off the wall. Waited 30 sec. Plugged it back in. Read 74 deg.
I'm not sure about the latest firmware. It still looks like it could be a communication error, it could wiring or due to a bad controller board or thermostat. Probably need to get the installer to check with WF to see if there are any known issues or suggestions for how to isolate the fault.
