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Help ! Geo is not working correctly.

I’m having problems with my geothermal system. A little background: I rebuilt my house about two years ago, increasing from 1600 to 3000 sf. I had an entirely new heat system and duct work installed with a Bryant geothermal 4-zone system (model # 50YD072JCB311) and 6 wells with 250 ft depth to ground water.

Looking back, I now realize it was not working correctly from the beginning. The first winter was mild and short when we moved back in in February 2011. The AC seemed to work ok but always felt like it wasn’t really cooling the second floor correctly. I noticed significant problems the second winter. The fan on the system was constantly going into high speed. When I checked the thermostat, it was flashing Aux Heat which is for the electric resistance heat. The HVAC person came by and said problem was the compressor was overheating and was shutting itself off for safety. He felt there was not enough air flow and disable/opened the 4 different zones, so it was running off only the main thermostat. Again, it started going into Aux Heat, so he replaced the thermostat designated #2 out of the four thermostat/sensors in the house. Said there had been a programing problem with it. did not correct the problem. He then added a large piece of duct work to bypass the basement zone baffle. He explained that in winter, extra heat dumps into basement and extra cooling dumps into second floor. Does that make sense? I explained I had noticed that as it gets extremely cold outside, we start having this problem inside. He said the outside temp sensor shuts off the outside unit when the temp drops below the efficiency point. I ask why this needed to happen since we don’t have an outside unit and use only ground source instead. His replied “Oh... that’s right!” He then told me he set the sensor as low as he could. Why have it at all?? This seemed to have stopped the unit from going into Aux Heat but the unit is still having problems and acting like it is related to the outside temp.

The other night I woke to find the fan was again running at high speed and blowing cold air. When I checked the thermostat, it was flashing ‘Replace Filter’ and that the inside temp was 65 degrees. This was again an extremely cold night. I had just replaced the filter one month before and our house has very little dust. That night, I’m pretty sure the unit never cycle off or was at least on fan the whole time. I manually turned the unit off, waited an hour, and turned it back on. Then it was heating again, but again, seemed to not cycle. Last night, we had single digit temp outside and the system again never cycled off, blowing at high speed all night long.

Today, it is just below freezing outside and the system has not cycled off. The fan is running at normal speed, and all zones show at or above the set temp. The other night, when it was running at high speed, I pushed the Next Zone button to check the temps in other rooms. Everything suddenly lit up on the thermostat panel and then went dark and then nothing. After a few minutes, the read out was back to normal. This morning it started to pump out heat and then went into high speed and blowing cold air??

This is not running efficiently. The fan is running 24/7, making the house feel very cool, and is drying everything out (plants, wood paneling, carpets, etc). This shouldn’t be happening! I was told at installation that geothermal systems don’t need humidifiers. Now I’m thinking I need to shell out another $1,000 for one despite what they said.

I do like my HVAC person and the company is very reputable, but I’m beginning to have serious doubts. Any help or suggestion's will be appreciated. Thanks


  • Possibly a Set-up Issue

    Not having the literature on the unit in front of me, I can only assume that there is an issue with the set-up/start-up of the equipment.

    These systems are equipped with ECM motors that modulate the rate of airflow to the conditioned space based on the needs of each zone. In addition, the compressor is likely a two-stage pump that can adjust its capacity based on the needs of the structure.

    Since your system has experienced abnormal compressor and blower activity, the first place to start is have your installer come in and make certain the controls have been properly set, wired and configured for proper operation.

    Any one improperly set DIP switch or improperly wired sensor can easily throw the system out of whack.

    Please keep us posted.
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