What details about this system do you know? Are there any records of it’s installation? Is it a DX or liquid ground loop? Does it work? Can you post pictures?

IMPO

SR

Liquid antifeeze vertical ground loops. There are three wells at 145 ft deep. They are all daisy chained and fed back into the house. Yes it works, I just want to know if I can verify the length of the full run.

I used to work electrical and I was thinking that if I drained the loops and used a blower to push a line through, but I think the amount of 90s would make that difficult. Then I thought that the only way would be to drain the antifreeze and measure the amount that came out. If there is a better way, I would like to know.

Out of curiosity what is the reason you want to drain the loops? What is the finial goal you're attempting to achieve, or for what purpose. I'd love to have a working geothermal system with 3 bore holes 145' deep and can't think of a single reason why I would mess with it and risk destroying it.

I want to verify the loop length. I know what is supposed to be there, I want to verify it.

Is there a need to know or just a curiosity?

If it ain't broke, don't fix it.

The unit intermittently goes into freeze mode and I am trying to figure out the issue.

At this point, I am just trying to verify that the loop length is actually the length that it should be. If the only way to measure the length of the loop is by measuring the liquid, then I think I have my answer.

If anyone else has a better answer I will check back later.

What’s “Freeze Mode”?

Judge the system by its efficiency and performance at Design Temperatures. Besides, what are you going to do if you’re 10, 20 or 50ft short, drill another borehole? You could. I wouldn’t unless performance was less than adequate in air-conditioning mode. That can’t be made up for like inadequate heating can be made up for with backup electric heating elements. Many older systems were sized based on cooling loads so they wouldn’t be over sized for cooling and any short comings in heating mode made up for with electric back up.

You never posted where you are and the particulars of your HP.

IMPO

SR

Has the system been maintained by a pro? Any reason to not call on them to address the problem?

I am in the northeast, so heating is more important than cooling.

I do not know what "Freeze mode" specifically is. The error is from a Bryant thermostat controlling a Bryant system. I do not recall the specific error, for this question, it is not particularly important. It only occurs when temperatures get into the mid 20s and below. This error, stops the heat pump from working and turns on the backup electric heating.

It is a fairly new system, so, yes I would have the installer drill the correct wells, if they are not correct. I do not want to rely on the electric backup heating as that would defeat the purpose of a geothermal system.

From what I have read, a geothermal system should be able to run all day, at any outside temperature in heat pump mode without needing the backup electric heat. We do not keep the temperature high, usually around 68 in the winter.

I have been relying on a professional installer. However, I also know that trust can only go so far. So verifying someone else's work is much more important to me than trusting that they will do the job correctly. Thus the original question of "How to measure a geothermal closed loop?"

These systems being pretty complicated and, of course, custom built, I'd think that only a second pro experienced with such work. would be qualified to assess and troubleshoot the work done by the first pro.

Re: HU-540232036

“I do not know what "Freeze mode" specifically is. The error is from a Bryant thermostat controlling a Bryant system.”

Sounds like you might have a ‘Split’ system. A geothermal HP & Bryant fan coil unit or an all Bryant geothermal mono-block HP.

Are you the original owner/purchaser?

“I do not recall the specific error, for this question, it is not particularly important. It only occurs when temperatures get into the mid 20s and below. This error, stops the heat pump from working and turns on the backup electric heating.”

Well that IS important because your efficiency is in the toilet at 20˚F and below - you’re on backup electric heating elements! You might as well have an air-source heat pump!

“From what I have read, a geothermal system should be able to run all day, at any outside temperature in heat pump mode without needing the backup electric heat. We do not keep the temperature high, usually around 68 in the winter.”

One of the main reasons to install geothermal or any system for that matter, is comfort. If you are comfortable at 68˚F, that’s great. The rest of your statement should be true but is dependant on its having been properly sized base on an accurate load calculation, indoor/outdoor design temperatures, proper installation and its monitoring for efficiency.

What documentation do you have for the installation? After our drilling was completed, I watched the driller drop a measuring tape unimpeded to the very bottom of each borehole that he didn’t extract till I told him that it was OK. You should have Hi-Rez pictures of this, depth of each borehole clearly indicated on measuring tape and photographed for future reference not only for own knowledge but also to show and hand over when the property is sold to a new owner or any home/building inspector.

You should have an, ‘As Built Book’ detailing all the design elements, installation details and complete, detailed, documentation, of the entire startup procedures. This is your system’s baseline, ‘EKG’ if you will, incase it ever goes into ‘Cardiac Arrest’ you’ll know what it’s supposed to look like when it’s running perfectly - if it ever did. You should have this documentation digitized and stored with all important docs associated with the purchase and sale of the property as well as a hard printout that stays in plain sight with the heat pump so that any new technician won’t have to waste hours or days trying to figure out what’s going on. ALL pipes, valves etc. should be marked and labelled including with fluid flow directional arrows. Every tech should date and document what was observed and done in a log book that stays at the heat pump, for the life of the HP.

You should have a complete schematic of the ground loops and runout locations referenced against permanent, fixed points and structures that are not likely to change or move for at least the next 50 to 100-years. Horizontal runout HDPE pipes should have metalized adhesive taped along the piping tops to make the runouts ‘visible’ to ground penetrating location/detection instrumentation, as bare plastic is much more difficult to detect without risky excavations.

What Make/Model/Serial# heat pump was installed, if you wouldn’t mind sharing that info?

IMPO

SR

Re: " Freeze mode" .... only occurs when temperatures get into the mid 20s and below."

WOW! Going into electric backup mode in the mid-20's on a geothermal system is just ridiculous; there has to be something major wrong with the system setup, etc.

Why do I say this? Because my geothermal design temp (-5F, Indianapolis) is probably not that different than what your design temp would be, and we went through -10F temps last month without electric backup coming on!

WATER FURNACE E048, 4 - 200' horizontal ground loops, 15 years old

@fsq4cw, You seem very knowledgeable and I appreciate your enthusiasm and technicality when asking me questions. However, I do not know if any of it helps me answer my questions.

Would having a short loop, cause the freeze error? That is the only reason for me wanting to know if or how to measure the ground loop.

There is no feasible way to measure your total loop length which I'm aware of without opening your loop and measuring the volume of fluid it takes to fill the loop. I've answered your initial question to the best of knowledge. As to your most recent question, a short loop would cause your problem without a doubt, But there are many different reasons why your system would give you a freeze warning and switch to backup. Personally I would not even consider a short loop as the cause until I've eliminated all other reasons, and to do this I would request a whole lot of data from you.

The fluid temperature from the loop to the heat exchanger, and refrigerant temperature is monitored and when a critical difference is detected it shuts down. There are reasons related to problems in the refrigeration system, and even problems associated with the loop that would cause the shutdown (and switching to backup), but rarely if ever would anyone suspect the contractor has shorted them on the loop length before eliminating all other more obvious reasons.

I could get into the reasons why and also the reasons to support the need for more information like how long has this system been in operation for example but I won't. What I will do is give you this link to a Geothermal forum which is populated with people in the geothermal profession who may be willing to take on your guery. good luck

The lowest fluid temperature will be seen at HP LWT (Leaving Water Temperature) point leaving the HP after the heat has been extracted by the HP on its way back to the borefield.

I still don’t know in your particular case what, “Freeze Mode” really means. You would have to consult the installation manual for your T-Stat.

More than being ‘short looped’ that might be a concern, I would want to know what percentage antifreeze you have in your ground loop fluid to determine at what temperature it will freeze.

Installing a Blue-White flow meter as I’ve previously suggested might also indicate the presence ice crystals in your loop fluid indicating that you’re heading for trouble. This device has many uses if you know how to use it, what to look for and how to interpret it. I would not own a liquid system without one.

You might need to have your fluid analyzed. You might also need to have your system flushed & purged of contaminants and air. You might also have an air-locked loop that would also lead you to believe that you’re, ‘Short-Looped’ when the issue is trapped entrained air effectively shortening the loop(s).

I would advise that you get your system serviced and evaluated properly!

IMPO

SR