I think that perhaps you have a number of separate issues here. Please see the link below to try to find a competent installer in your area to evaluate and repair you system.

Dirty air filters that may need replacing and not necessarily the compressor may cause some of your problems. Has the charge level of the refrigerant circuit been verified?

You seem to be saying that at some point this system functioned fine. Was that so in heating and cooling mode?

In heating mode the system should function with the heat pump supplying all your heat. Should the HP not be able to ‘keep up’, the Aux Heat should activate to assist the HP. Then when the set point of the thermostat is satisfied everything should shut off allowing the boreholes to relax and recover. The next demand for heat should be without the backup. The Emergency Heat mode should supply heat without the compressor and ground loops so you are correct in how the system operates.

How deep are your boreholes, how many, how far apart? How many feet of undisturbed overburden is there? At what depth are your runouts buried and are they insulated (this one is very important)? If your system is pressurized, does it have an expansion tank? Are the boreholes connected in series or parallel? If the system has headers are they buried or inside the mechanical room? Was the installation and start up procedures fully and properly documented?

What details can you provide about your system regarding HP size and all details regarding the ground loops including the flow center. Where are you located and what is the design temperature of the system? Do you have any means to check the flow rate in GPM, Entering Water Temperature and Leaving Water Temperature?

It sounds like you have a separate issue with the backup electric resistance elements as they should be able to fully heat your home on their own. Are they staged, if so does the staging work properly? It doesn’t seem so. Are all components of your system receiving power?

SR

Here is a link that might be useful: International Ground Source Heat Pump Association

Hello SR,
Thank you for your response! I will try to provide you with as many details as I have at this time.
I will share with you that I know it's not the air filters. Those are changed regularly, every 3 months if not sooner......checked monthly to make sure they are clean and changed if they are not.

I have had system for almost 13 years. Majority of the time it has worked well. Heating and air conditioning. Occasionally some issues, but once they were fixed, system functioned well again. I have had the same horizontal well loops. Not an issue in the summer with cooling, and generally is not an issue in the winter unless we have several weeks of extreme cold in a row. I understand that at times of extreme conditions the ground source heat pump may not be able to keep up. When system has an issue, repair men blame the well loops and recommend having new ones or more installed, at a big expense. But, I don't see the point of doing that if the issue is still the Trane unit itself or the electric coil unit. When the furnace is working well and all connections are made properly, the loops are not a consideration.

The unit is a TRANE Command Aire,
model #GSUFO301BE1L120C
Serial # W99K51763
Unit is located in my dry heated/cooled basement area.
I am located in Iowa. We get winter temps with the extremes of below 0 degrees and summer temps up to over 100 degrees.

Lines were placed in a trench 120' long, 1 loop @ 6'-7' deep, 2nd loop @ 4'-5' deep

I am not certain at this time the water in and water out temp, or the other measurements you mentioned. Although I would be willing to find out. I will note that I keep watch of the water tank and it is at the proper level. At one point there was a leak in the tank connection in my house. I questioned if the antifreeze would have leaked at that time also and if more needs to be added now. The well diggers did not think that adding more antifreeze would make that much of a difference.

I will also note that the freon level was checked by repairman and more freon was added. The unit acts the same now as it did before the freon was added.

Thank you for clarifying that the way that the Auxiliary heat and Emergency heat work. That makes me wonder again if the issue is with the electric coils. In the past, I didn't need to manually switch it over to Emergency heat for it to run when the ground source could not keep up (unless I needed to give the ground source a break and run it on Emergency heat only.) Also I don't remember it being uncomfortable when I had to run it on Emergency heat during very cold /extreme temps spells. The unit does not switch from the compressor to the electric coils automatically, when the compressor can not maintain the temp.....the compressor shuts out but unit continues to blow cool air.

I appreciate any help or advice that can be given.

This post was edited by treasureagain on Wed, Apr 3, 13 at 2:04

"Lines were placed in a trench 120' long, 1 loop @ 6'-7' deep, 2nd loop @ 4'-5' deep"

How deep is the frost line depth in your area? It seems 4 feet is cutting it close. Shouldn't the horizontal loops be much deeper than this?

I am no expert on Geo HPs but wasn't Trane Geo HPs just a rebranded model from another GEO manufacturer?

And who s performing your repair work? Have you contacted your installing dealer?

IMO

"How deep is the frost line depth in your area? It seems 4 feet is cutting it close. Shouldn't the horizontal loops be much deeper than this?"

Hello, thank you for your responses. The lines were dug by a well digger that has dug wells for years and my father was there at the same time, who both knew the frost line depth level for this area. The loops work fine, when the furnace unit works properly. Other then the occasional extremely cold spells, which I understand and would then run on Emergency heat when the HP couldn't keep up.

I'd rather not say on here who was performing the repair work, other then I did hire someone that works with geothermal furnaces. Also, I did contact the installing dealer.

Thank you again.

It would seem to me that if you put it into Emergency mode, only the electric coils should operate. And if they don't, then that problem should be tracked down and fixed.

There is a problem with the electric resistance heating and its sequential operation. With all breakers ‘On’, the backup should active automatically WITH the HP (compressor ‘On’) when a demand for backup is called. This should be when either the temperature of the house drops 2-degrees or more below the set point or when the HP compressor has been running continuously for a pre-programmed period of time, that could be 45-minutes or more. Then backup comes on with the HP compressor. When the thermostat demand has been met everything shuts off and resumes ‘normal’ operation with the next demand, that is HP no backup. Emergency Heat should be electric backup no compressor, just blower.

These issues are strictly electrical, programming of thermostat and HP control board.

I don’t know what city you’re in or near so I can say what the ‘design temperature’ should be. I’ll make some assumptions about your system based on the information provided. It’s a 2-1/2 ton HP, 4- pipe linear horizontal non-pressurized ground loop with no expansion tank and a ‘QT’ Flow Center. As such, being non-pressurized, there is a reduced likelihood that the horizontal loops have lost contact with the ground due to contraction as a result of reduced temperature. However, it is important that you verify that the antifreeze level of the fluid in the ground loops is at least 20% as it would be quite normal that fluid level temperatures, particularly Leaving Water Temperatures (LWT) could be 25 degrees Fahrenheit. These (normal) temperatures below freezing might put your ground loops at risk of bursting should they freeze. That would be a disaster!

Other issues are that your ground loops may loose contact with the earth during a prolonged dry spell. It is normal and highly desirable to have all ground loops installed with a ‘Soaker Hose’ or line and a HP selected that can monitor this condition and when called for activate a circuit, usually a solenoid, to turn ‘On’ the ‘Soaker Line’ to automatically rehydrate the earth so that the HP can resume ‘Normal’ operation.

Does your system have a ‘Soaker Line’ buried below the frost line?

Based on what you’ve indicated about your system operating properly when ‘fixed’ I’ll assume for now that your ground loops are sized correctly.

Another factor that might be in play here is, is the flow rate high enough to generate ‘Turbulent Flow’? You need a contractor that knows about this and can verify the ‘Reynolds’s Number’. Basically, what you need is a flow rate of at least 3-gpm/ton to achieve turbulent flow and complete mixing of the circulating fluid in the ground loops. If flow rate drops below this figure, what you have is ‘Laminar Flow’ where the circulating fluid stratifies in the ground loops, circulates in a linear fashion as opposed to a turbulent fashion, and does not pick up all the heat from the ground that it was designed to.

It is for these reasons that I recommend the flow meter linked to below. This device will allow you to verify the flow rate and unlike a straight gauge like a circular temperature or pressure gauge, will allow you to see the fluid and watch for air bubbles that will impede the flow, reduce the heat transfer and possibly degrade the impeller on the flow center circulator pump (which should be verified as well). However there is a reduced likelihood of bubbles in the system with the ‘QT Flow Center’.

Does your system have a ‘Desuperheater’? If so please discribe it along with the buffer tank configuration and plumbing.

SR

Here is a link that might be useful: Flow Meter