for the third time today my geothermal is running (the fan) but the compressor is not running so the house is very cold

generally shutting off the heat cycle or powering the unit down and then all is back to normal but something is causing this, apparently when it is cold outside

i have a pond slim jim.  the green light on the circuit board is on, how do i figure out why this is happening? i have a comfort aire hrv060

Assuming proper air flow, i.e., not tripping out on high head from dirty coil or air filter, the next place I'd look would be freeze protection - some sort of flow problem such as inoperative pump, air in line, fouling of heat exchanger causing unit to drop out on low waterside coil temperature.

I'm not familiar with your particular unit.

Not sure on your unit, but as a private label Climatemaster, it may have the same selfdiagnostic feature. Check the book. It sounds like a lock-out condition which could be caused by lots of contributing conditions.
Have you contacted the installing contractor?
J

There is a couple of things that could cause this. The system somehow lost pressure, though unlikely and you do not have flow through the heat pump. If flow is verified in the heat pump via pressure delta, then you probably have a temperature issue. The temperature is too cold. Did the installation include antifreeze in the water side of the system. If so, JW3 should have been cut and the system will function at a lower loop side temperature. This is located on your control board and is just a jumper that is clipped for operation of refrigerant temperatures down to 10degF, assuming antifreeze is circulating thru the slim jim. If this has all been done and the compressor still won't run with flow confirmed, the problem is internal with the unit. Hope this helps.
Dan

We have a Climate Master Tranquility closed loop horizontal heating system installed in our newly constructed home. Since day 1 of start up in June 2009, the loop temperatures have fluctuated (causing some concern to our installer who is new to this field). Last week, our thermostats began flashing pink with an error message saying "low water temp contact service". We are now running on emergency electric heat (So much for the $ savings!). Our installer is getting the runaround from the manufacturer and varying information from "Add antifreeze to the system" (which he doubts would resolve the problem) to low flow rate.

HELP!???

I am not an expert. Talk to your installer to find out if your unit is adequately freeze protected and have the installer review the "Low Water Temperature Cutout Selection" in the installation manual.

What type of loop do you have?  What do you mean by loop temperatures fluctuating?

We have a closed loop horizontal 4 pipe system buried at 6' and 4'.  We do not currently have antifreeze in the system.  By fluctuating loop temperatures I mean the readings from the thermometers at the pt ports
 show the system has widely fluctuating temperatures instead of the anticipated "constant 56 degrees" range we were expecting!

What part of VA are you in? Our frost line in SW VA is roughly 2 feet. You may not need antifreeze at those depths (and at your location) - need to ask your installer to be sure.

While the ground in general can maintain a constant 56 degrees (or whatever the ground temperature is in your area), it is ok, and expected, for the ground temperature to vary near your loop. This happens because the loop transfers heat to the ground in cooling mode (EWT rises), and the ground transferring heat to the loop in heating mode (EWT drops).

As long as the EWT is within the designed temperature range of your equipment, and it is freeze protected (if needed). All may be well.

Please tell us specifically what is your EWT (entering water temperature) (going from the loop into the geothermal unit)? If you have a Tranquility 27, the manual states that the Minimum entering water temperature is 20f. You may need an antifreeze solution added to your system, or it may simply need an adjustment to the "Low Water Temperature Cutout Selection", or both, or neither. We need your EWT information. Also, how ling is your loop, and what is the size (Tons) of your system? A model number would be good information too. Help us help you.

The EWT is 38 degrees. The installer was told he should add antifreeze and clip a wire on the circuit board to prevent the low temp cutout.  He knows this will keep the unit running, but he wonders what the benefit is in having the geothermal system if the temperatures in the system are rising to match the temps outside and dropping to match the temps outside instead of leveling off at some point to a "constant temperature". We have three units a 5 ton, a 4 ton and a 2 ton with 5,500 feet of loop.  The installer has checked the pressure drop across the coil and it seems within range and done a building load calculation that appears correct.

Sylvia,

The installer is badly misinformed about geothermal systems.

The ground might be 56° but as soon as you start pulling heat from the ground your loop temp will start dropping.

How far it drops depends on how much heat you pull out of the ground and how much loop you have in the ground.

It is not uncommon for loop temps to drop into the 30°'s.

If the EWT is 35°, then the LWT will be below 30° hence the need for antifreeze.

So you should add antifreeze right away and then clip the jumper.

Don't worry though your heat pump will still work very efficiently even with EWT of 30°

You have 500 feet of loop per ton. We were quoted the same amount from most, but not all, installers in our area. Should be ok. Coincidentally, our EWT is the same as yours.

It sounds like the plan your installer has is a good one. What freeze protection does your installer want to use (in degrees)? Will he use methanol? We have our loop protected down to 15 degrees at my request. Our installer typically protects down to 30 (I think that is correct). I don't know why installers do this in this area with horizontal closed loops. Anyway, you don't want too much (more than you need) antifreeze because it can hurt heat transfer (so I've been told). It would be nice to hear what the pros believe freeze protection should be in this area???

Keep in mind that where our house is, December was 19% colder than last year and 28% colder than the year before that (based on heating Degree days HDD). Maybe it was colder where you are too?

Benefits to Geothermal with falling loop temperatures in the winter? Geothermal systems can outperform air source heat pumps even at low EWT. Our 3 ton WF Envision unit can get 3.36 COP at a loop temperature of 20f! I doubt an air source heat pump can get close to this COP when the air temperature is 20f. Also, I read somewhere that the average life expectancy for geothermal units are approximately 25 years. Average life for an air source heat pump is MUCH less.

Do you have 3 thermostats? Do you have some kind of zoning system or do your thermostats work independently? Do you have areas of your house that are unoccupied for long periods of time (8 hours at a time)? In my non-professional opinion, if there is no interconnected zoning, setting back the thermostat 2 (or 3 degrees at most) as part of a thermostat program, may possibly provide some benefits to your loop if you have a smart or adaptive intelligent recovery feature enabled on your thermostat. I like using 2 degrees since there is little chance auxiliary heat will come on to help the system recover. The only exception to this is when the outdoor temperature is near the design temperature of your system. I don't set back when this happens. Not everyone agrees on setback philosophy.

P.S. I know nothing about interconnected zoning, so I don't offer opinions on systems that have them.

I would monitor how low the EWT loop temps drop over the winter. 

If they drop to:

25°  I would add more loop

30° I  might add more loop  depending on the cost

35°  I probably wouldn't add more loop.

Funny on your location. I used the weather data from Roanoke regional airport for the December temperature calculations. If you would, PM me who your installer is. I'm curious, and our neighbor may be interested in a system too. This way, they can compare WF to ClimateMaster.

500 feet per ton is what 4 Water Furnace installers quoted us, and we are only 20-25 miles from you. I'm not a pro, but it sounds like installing the antifreeze to provide proper protection and adjusting the Low Water Temperature Cutout Selection may be all you need. I requested 15f for our system, but I really don't know what the proper protection level is for our area. Is there any Pro out there that can advise on the amount of protection Sylvia needs?

Should you add more loop? I would wait and see what your EWT is at the end of the winter and post a new thread with that information. You may not need more. We have 600 feet per ton, which was more than all the other quotes we obtained, but your loop is one foot deeper than ours. Everything may be fine as is.

Dewayne, I am still learing. Why add more loop at 25 EWT? I know Sylvia has a Tranquility system, but our Envision gets over 3 COP at 20 degrees. Is the Tranquility similar (I don't see this information in their literature)?

Climate Master does not recommend operating at temps less than 25°

Thanks. Guess I can go to bed now that I've learned something today!

LWT will be below EWT, and 10F provides a safety factor.