In 2008, we installed our geothermal system with a local, "reputable" contractor...a very large company. WaterFurnace unit with closed ground loop replaced a gas furnace. We chose Geo for energy savings and to be a little "greener". Since a month or two after installation, I have regretted our decision. Nearly 14 years later, I don't believe our heating system has ever worked correctly. We have a 15 year warranty, parts and labor. The contractor has visited approximately 25 times to fix problems....in addition to twice annual maintenance calls. The contractor has replaced many items, including the compressor, zone boards, desupraheater, zone controller, thermostats, re-wired everything, blah blah blah. They have sent out 7,8 different techs over the years. All have a different story about the Geo unit. Working great! Not working great. Aux heat should rarely supplement the heating. Aux may supplement when it is 30 degrees and windy outside. One "disconnected" two of the Aux heating elements. Next tech says that all are engaged. It goes on and on. The latest is that the Geo is sending too much airflow to Zone 2. He can't set it any lower. Our duct system cannot handle that much airflow. Mind you, they sized and installed the system. Why am I posting? Do NOT buy a Geo unit unless you have several references and COMPLETE trust in the installation company. Are they experts? How long have they installed Geo units with that manufacturer? Also, the latest tech informed me that regular heating pumps have up to 76 stages now and are more efficient than Geo.

Sorry for your problem. I have a open loop system the same age and have had zero problems with it. But the problems you are having seem fairly common. I talked to a guy the other day who had replaced a 30 year old heat pump, as he thought it was at the end of its life, and a new unit should be more efficient. The new unit has been in for almost 7 years, and he has had noting but problems. My 15 year old system and his 30 year old system were standard single speed units. His new system is variable speed, and has a electric operated ball valve, both of which are the main source of his problem. I believe some of the newer technology is more trouble than it is worth. Not only are there lots of fancy bells and whistles to maintain, but you also need technicians capable of maintaining them. Since you can't find good help to replace even a simple light fixture or change the oil in your car, finding someone qualified to work on a complicated heat pump is next to impossible. As you have noticed, having several different techs on location will get you several different suggestions on fixing the problem. None of them are right.

If you need a cell phone or computer worked on you can find plenty of qualified techs. But finding someone qualified or that actually gives a damn about pump, plumbing, HVAC, or other technical fields is next to impossible. I try to keep my systems simple and mechanical with as little electronics as possible. That and if/when there is any work needed I have learned to do it myself is the only reason my systems work well and haven't given problems in many years. "Knock on wood." Lol!

Geothermal (more properly called a ground source heat pump systems) almost always have a negative return on investment for residential projects less than 10,000 square feet...even when the system works flawlessly for 20 years. Ground source heat pump systems start making economical sense for large commercial projects when designed and installed properly. Now if you have a Geothermal hot spring on your property, that is something to get excited about...

I agree for the most part. But pump and dump systems can be efficient if there are flowing wells, springs, or other things where the free energy can be utilized. In my case I have 4 GPM of 66 degree water flowing past 24/7. Open loop systems don't make much sense if you have to pump the water from very deep and are wasting water to do it. But if the water is shallow and/or already flowing by, might as well use it. I think closed loop could also be efficient if the loop is in a flowing aquifer or something that wicks away heat easily.

Just to be 100% clear, I never said that ground source heat pump systems were NOT efficient or NOT high performance.

Ground source heat pumps can have a Coefficient of Performance (COP) of about 4.0 (heat pumps don't convert fuel energy to heat energy...they just move existing heat energy from outside to inside). Air source heat pump systems only have a COP of about 3.0. Electric boilers only have a COP of 1.0 (100% conversion efficiency from electric energy to heat energy). So there is nothing with a higher level of performance than a ground source heat pump system except for true Geothermal which has a near infinite COP. But high performance is only part of the heat source selection process...

The problem with ground source heat pump systems that makes them a poor choice for residential projects is two-fold...they have a huge acquisition cost compared to even expensive air source heat pump systems...and they are even more complicated to design, install and maintain compared to air source heat pump systems. So even though your monthly operational cost MAY be less than some other heat source option, you never come close to recouping the cost of the system...hence negative return on investment. And this assumes you can get your ground source heat pump system to operate properly and live at least 20 years...which seems to be the rare exception rather than the average typical experience...

And I said MAY because often times even a relatively low cost mod con gas boiler that only has a COP of about 0.95 (95% conversion efficiency from gas fuel energy to heat energy) will have a lower monthly operational cost than the most efficient ground source heat pump system if the local cost of gas is sufficiently lower than the local electricity cost...which is more often the case than you might initially think.

The best thing you can do is design/build a building that requires the minimum energy to cool and heat it. Once you get to small building energy requirements, the performance of the HVAC system starts becoming less important making the acquisition cost the more important selection parameter.

Again I agree. However, I don't think acquisition cost of an open loop is very expensive, especially if you are using an existing well or water source. But the cost of all those loops and loop wells make the closed loop systems much more expensive.

Anything that has the potential to change water temp or create pollution or not use water in beneficial way is not looked on very favorably here. So open loop is illegal here and likely in other States too that actually regulate water use for the public well-being instead of just business profiteering. Lots of effort and money is also spent here to remove dams and plant trees to improve water temp and flow rate for fish conservation. We are personally very active with this endeavor:

https://www.borstengineeringconstruction.com/WaterWatch.pdf

This is a really interesting thread, thank you. I live in New Zealand where geothermal heating is not uncommon. I'm in two minds of going in this direction, so I'm looking into it as much as I can. Do you think your system was affected by your location?