Pond Boss Forums INTRO Questions & Observations Geothermal Heat Pump

I would definitely check the performance of the pond loop. Here are few more hints:
If the inlet temperature is low after the HP runs for a while the loop performance is poor either due to too dense winding of the pipe or air trapped inside. If the inlet temperature is OK but return from the HP is low the flow is not adequate. It might be caused by pump cavitations due to low pressure in the pond loop, one pump in dual pump system not working or some restriction in pond loop. There is a pump curve and expected pressure rise (head) in the HP installation manual. If suction and discharge pressure are measured the chart could be used to read the flow rate etc. Low head means high flow rate and vice versa. Listen to the pond loop pump while it is running. It should emit monotonous hardly audible sound. If the sound is "whooshing" or varies in intensity the pump cavitates or there are air bubbles passing trough. If I recall anything else I will post it.


If you have digital steak thermometer use it to check on on the temperatures. It is imperfect but it will give you at least some idea if you need to invest in or borrow the infrared one. The heating season is almost over and you will run out of warranty. You need to find the problems soon. Refloating and fluffing the pond loop isn't that difficult. Based on the pics you should have enough pipe there.

ok, I see. That's not too bad then. Since this will be new construction, wasn't sure to have the duct system already in place. How did you find your geo installer?? Glad to know the humidity is taken care of and we don't need yet another thing for that. We have a heat pump now. Is it alot like that? Except for of course the absence of the ugly noisy outside unit by my bedroom window.

Ladia, thanks I believe you have us on the right track. Install is coming out on Tuesday morning (yes, warranty getting close to running out). The heat strips ran all night, they never shut off...when we got up at 6 a.m. it was 7 degrees outside and 67 in the house (thermastat set on 70). By 6:30 a.m. the temperature had dropped to 66. Hubby went down after I told him what you said and shut the heat strips off. When he came back from his route at 8:30 a.m. it had warmed to 12 degrees outdoors and dropped to 63 degrees in the house. He had stuck a meat thermometer in the vent and the air coming out was 59 degrees so he turned the heat strips back on. And the vent temperature went back up to 100 degrees. Hubby put heat strips back on. Sometime shortly thereafter (est 9:00 a.m.)I called him after speaking with geo people and they said to have him turn off the thermostat and wait a few minutes and restart it (i forgot what they said, but it would do something to the compressor???). He turned it off and then back on at 9:30 a.m. it was 14 degrees outside and 63 in the house. At 10:00 a.m. it was 16 degrees outdoors, 64 degrees in the house and the air coming out of the vent was 125 degrees. By 10:45 a.m. it was 17 degrees outdoors and the house had warmed back up to 70 degrees and it's been running either on fan (or Phase 1) only the rest of the day the temperature has been 69 or 70 in the house and the temperature coming out of the vent is 85 degrees. So, my hubby's thought is theat the geo wasn't geo'ing at all until we turned the thermastat on and off. Thoughts?

On Tuesday the geo installer will be here with equipment and do a lot of testing and checking (not to mention I requested a thermostate that will tell me when the heat strips are on). Depending what they find, they may call the sub that did the actual pond loops.

I suspect with the heat strips off, the combination of the low return air temp an low entering water temp caused the unit to fault. Probably on low water temp. If you're currious you may be able to see the last fault from the service menu on your thermostat. You can definatly see it on the control board in the heat pump unit. You might quiz the contractor when they come out.

Will do. Hubby is writing down things to ask the geo installer when they are here on Tuesday. Thanks.

Definitely ask questions about the pond loop.
What is expected flow rate (it is in the installation manual) versus actual. They should measure head of the pump(s) and read the flow rate from the pump chart.
Is the pump sized correctly?
What is the temperature in the pond?
What is the temperature of inlet coolant from pond loop after the heat pump starts running? It shouldn't drop by much. Large drop of the temperature is a sign of poorly performing pond loop.
What is the return temperature of the coolant downstream of the HP. Too large differential between inlet and return is a sign of low flow rate.
What is the pressure in the pond loop?
Is it large enough to prevent pump cavitations?
Was all air reliably purged?
Assuming that the loop is filled with propyleneglycol based coolant what is the freeze protection in the HP set to? If it is set incorrectly (in example for open loop) the protection might lock up the heat pump.
Call another geo installer or technical support of the manufacturer of your system and ask about expected temperature differentials, pond loop pressure, flow rates etc.
Knowledge is power. Don't let them BS you.

One option you might consider instead of having the thermostat replaced is to install an outdoor temperature sensor. This will lockout the heat strips unless the outdoor temp falls below the setpoint. Minimim setting is 5F in five degree increments.

If you look at page 49 of the installation insructions I linked to there is a troubleshooting form that will gather the information to answer many of the questions Ladia refered to.
It would be good to have this information anyway for future reference in case the geo contractor decides to retire and the system needs service by someone else.

I would give the contractor an opportunity to step through this. There are several possible reasons the system is not performing to expectations. THey are all objective.

The geo system may have a problem or not be setup properly. The form I refered to will direct them to that.

The air side of the system may have a problem. Checking the static pressure and the fan speed settings will detect a too restrictive system. Further checks of static pressure and temps can dectect leaking returns or supplies.

The pond loop may have a problem. Ladia covered alot there.

The system may not be sized properly. You said they did a load calc. You can compare.

The building envelope may not be performing per the load calc. This gets a little subjective because they have to do a best guess baring a full energy audit, but were their assumptions reasonable.

MarkECIN, I'd hate to see your power bill for this month. Sounds like you did what you had to do, though. I unplugged my heat strips inside the unit to be sure they never come on. The brain surgeons at WaterFurnace put the compressor on one circuit, and the heat strips and blower motor on another, so I can't just cut off the breaker.

southernbelle, I found my installer at a home show. I am sure any geo manufacturer can give you a list of local installers. I can send you the name & number of my pond loop guy if you want.
Yes, it is just like a heat pump without the big ugly outside thing.

Look HERE

Jersey, I'm sure glad they did put ours on a separate breaker. In all honestly we are confident with our geo installer and their knowledge. I truly believe these systems are quite complicated and as Ladia has displayed over and over again with his knowledge things can and do go wrong. And, boy, are we learning here. Yes, I sure wish I would have disconnected those strips sooner (or been more persistent on the geo person that there still lay a problem besides the transformer replacement by the electric company) and not waiting for their staging question to be answered. Our system was a newer line so I'm sure there is some learning for the tech too. I sure hope I don't get another surprise next month like I did this month (I have even been reading the electric meters and right now my hubby has had to reset the compressor by turning the thermostat off then back on a few minutes later and that seems to reset and the geo then works fine--hardly hear it running. BUT, by far this is a temporary fix until next Monday by the geo people. I will note their findings (so future homeowners who are looking at geo have light of problems many of us have had and learn from our misfortunes.

Question....when things go wrong with the geo system, even if it's not still under warranty, do they help pay on the power bill? If it's something they did or didnt' do? Doesn't seem right for you to have to pay it all if the unit is defective or not installed right. Can't wait to hear what they have to say. Guess the one thing I've learned from this is put the strips on a separate breaker and be sure they are turned OFF!! We have AUX heat on our heat pump and when I see that light come on--I turn the heat down and put on another sweater :~(

Typical geo heat pump has about 400% efficiency (It doesn't make heat it transforms high volume of low intensity heat to lower volume of higher intensity heat.). So if it would work correctly your electric bill should be about four times less.

MarkECIN,
If I understand correctly what you are describing I would caution you about continuous or repeated resets. Unless your contractor has told you otherwise and you are sure they will assume any liability. It's not a good idea unless you understand exactly why the system is shutting down. I would turn the strips back on. Talk to your contractor and get them out sooner if possible.

If the issue of not working is related to the thermostat reseting will not hurt anything. There is a display on the heat pump showing the staus and/or error codes. I woulld suggest to look at the display when it stops working.
In example of Waterfurnace:
The light MASTER MODE and HEATING should be lit while the display shows the temperature.
If the LOCKOUT is lit then the display will show the error code.

It's important that the contractor sizes the unit properly and will warranty that aspect of their services. I would see to it that this is put in writing.



It goes against the conventional wisdom here, but I would urge caution in regard to disableing the strips. It's not a good thing to come back from a weekend trip to a flooded home because the pipes froze and burst.

we rarely have that happen here. We are really in the Deep South! About 2 hrs from the gulf coast. But we do cover the faucets outside in the winter. Can't remember if we ever had any pipes burst except for in an old house we lived in when we first married.....uninstillated. brrrrr

The temperature will not drop to freezing while the house is inhabited. Even if you leave for a day. Going on vacation is another story altogether. So I will rephrase my statement I would virtually disable the heat strips. In other words they should come on only at quite low and uncomfortable temperature.

I'm with you, Ladia. If the geo system was working correctly, the heat strips should have come on only in extreme instances. I know the geo installer had problems with phase settings and called the manufacturer (and we never heard back so we didn't think it was that urgent). Obviously something went bad wrong to have such an electric bill...they should offer to pay back part OR they can give me my next year service agreement no charge. I would have expected an electric bill of maybe $250ish total for the house. We shall see what they come back with.

I hope others, especially those looking to go geo, are reading these posting and learning as I certainly have learned a lot. dot

Service agreement? How much is that a year?? At the cost of these things, they ought to service them forever!! If it's a fault of theirs, sure they will work something out. I'm reading and learning-thanks for your post! Sorry this had to happen to you. I'm hoping we won't have this heat strip problem since it rarely gets very cold here. I'm positive the pond will never freeze!! I've always dreamed of a frozen pond growing up to ice skate on!

I've got to jump back in here and say that I think it is a misconception that a geo system is some kind of complicated, mysterious, or delicate system. It is no different than a run-of-the-mill every day conventional heat pump, except that it exchanges heat in water rather than in air. It is because this exchange is so much easier that geo systems are incredibly efficient. So instead of having a noisy fan blowing cold air through a coil under your bedroom window, you have a coil of plactic pipe soaking up heat at the relatively warm bottom of your pond.

Conventional heat pumps have heat strips too. If there is a system malfunction or circumstances cause the heat strips to come on, the high electric bills will result just the same.

Now if you build your own control system or use a heat pump (geo or conventional) to heat radiant concrete floors, we have a whole different thing going on. Nothing wrong with either of these things, it's just that they would add complication to any kind of system. I intend to use my system to heat 2200 sq.ft. of radiant concrete, and when I do, I'll probably look into building a Rube Goldberg control system for it myself.

When I was shopping for my geo system, I looked at several manufacturers. What I found is that there are no low-end geo systems. They all are high quality units, and this is reflected in their price tags. I went with the WaterFurnace because my neighbor was happy with his, and I got what I thought was a reasonable price from the installer. With the exception of a few start-up bugs with the zone system, my geo system has been out of sight and out of mind. Except when the electric bill comes. That's when I know I made the right decision to pay-up for it.

I would hate to see anyone with the opportunity to put in a geo system, which is almost everyone on this web site, not do so because of a fear that it is complicated or unreliable.

SO glad you posted this Jersey! I had the same impression you just gave.... at first.... that Geo systems are pretty simple, especially the pond loops. I'll admit the more I read here, the more confused I get. I'm not really worried about all the technical stuff-my husband is an engineer and I suppose he'll figure it all out in due time if needed. I sure don't want to spend this much money and have all these problems! I'm sure like everything else there will be a few minor problems. We will probably go with WaterFurnace also, mainly because you use it and don't seem to have many problems (and also that we are in the same zone). I wondered too if there were any 'bargains', but I see they are all going to be basically the same. I'm content with the fact that we are able to use the pond and will save a bundle there. We are going to put off building the cabin a while until the economy picks up a bit, in case we need to help the kids out. The pond is still on, soon as they can get out here. I've learned SO much here and sure I'll be around when we start this pond. I get more excited every day about the Geothermal, which we have pretty much decided we are doing. Jersey-at what point do we need to contact the company? I was wondering since we will have a basement, should we have tubes or anything else under the slab?? I'm wanting to leave the concrete and stain it, using throw rugs. I know it will be cold down there. The main floor will be all wood floors.

southernbelle,
I put pipes under my basement slab for the geo system, then the loop guy told me they were the wrong size, so he ran new pipes overhead. I wish I had contacted him earlier. So the answer is YES, invite the loop installer over before you pour the basement floor. You also might want to look into putting PEX in the basement floor for radiant heat. It doesn't cost much, and you only get one chance.

Thanks! I'll look into that. It's possible we may go ahead and start on the foundation ahead of time, so glad you told me that. I guess when they come they can look at our plans and give us an idea on what to do next. Tell me this, does radiant heat make just the floor warmer or help warm up the room? I think I remember you mentioned this was a whole different set up from the geo. How does this work? Is this a do it yourself project? Do you think we will have enough hot water in the winter to run this? I found this site on the PEX diy http://www.pexheat.com/

The geo systems are somewhat more prone to initial problems due to the fact that the ground or pond loop has to be correctly calculated, has to be made in the installer's shop and has to be correctly isntalled etc. In other words the experience and skill level of the installer is important. Also geo might have several more heat exchangers with associated pumps and temperature control that are all based on the particular house. In other words there are more components of the system that are custome built or at least custom configured.
Air based HP are factory made and therefore all the componets should be well matched and asembled correctly.

I would recommend PEX with oxygen barrier. It isn't needed for geo but you might add in example wood boiler later on. Oxygen barrier is important for corrosion protection at higher temperatures that boiler can produce.