Geothermal Radiant Heat Unit Won't Run Troubleshooting

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BobD777

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Hey All-- I've got a bunch of Earthlinked DX geothermal units in our house. One of them is a Classic Series that's used for radiant heat in various rooms throughout the house. I love the system, but the company went out of business a couple of years after we did this huge installation--so no more warranty.

The question I have is about the one unit we have for our radiant zone. I'm hoping that even an HVAC/refrigeration person not familiar with Earthlinked might be able to help me figure out what my current problem with the unit not kicking in might be.

A bit of background first. I had just finished flushing the Boiler Buddy water tank that stores the water for the floors. After doing that I turned on the unit and raised a couple of thermostats. I think I heard the compressor kick in, but am not sure it did before I left. When the floors weren't warm in the morning, I went down to see what was up. The unit was not on. There was power in the unit, but it was not operating. I checked all the valves to the tank that I had turned off, and they were all open. However...

... the valve from the hot water tank to the geo unit was closed. I can only guess that happened when my HVAC guy came over to do some work, and I could have asked him if anything should be closed for the winter--and then I forgot about turning it off. Anyway, I don't know why it was off.

So the question is first, could that closed valve from the hot water tank to the geo unit have caused the problem? And if so, any idea where I might look for that issue? I would think some protection unit would have kicked in.

In addition to the unit not turning on (the compressor), I see that there's no power to the circulator that brings the water from the tank to the unit. So I guess whatever turns on the compressor also powers the circulating pump? The power wire for that circulator comes from something called a lock-in relay, where that terminal has no power, of course.

I already tried turning off the circuit breaker to the unit and letting it rest for a while. All indicator lights on components within the unit are reading normal.

Here's the manual for the unit:

Here's a pic of the electrical parts below. Power supply on the left, that brown lock-in relay next to it.

I know it's a longshot asking this, but figured I'd give it a try. Thanks in advance to any brave, smart soul who responds :)
 

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John Gayewski

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You need a meter to trace what has power and what doesn't. It could be the circulator is ruined and there's a sensor keeping the test of the unit from operating. You really have to just work your way through the power operations to track down what failed.
 

BobD777

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A big "sorry!" to those who responded to this thread, months ago. As life has it, I had to leave this project for a while to deal with big family health issues--which I'm still in the midst of. So the floors remain cold.

However, I will hopefully be getting back to this very soon and so appreciate the feedback, since I really need it!
 

BobD777

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Do u have a full blown system? Nothing works? Looking for a wiring diagram. Do u have a meter? What works and doesn't.
Hey Fitter... 2 years later :-O
Here's the manual for the unit: https://www.manualslib.com/manual/1346419/Earthlinked-Avs-0030-A.html

And what do you mean by a full-blown system? I have a bunch of geothermal units that heat various zones in the house with forced air, and I have this one unit handling all of the radiant heat zones.
I have a basic multimeter, as well as a voltage meter.
All of my other units are working fine. But this hydronic unit for the radiant is not working. When I power up the unit, all the lights that are supposed to come on in the unit do light up. However, the main circulator pump does not light up or turn on. Each radiant zone's circulator does power up.
Any suggestions are appreciated. Thank you!
 

BobD777

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You need a meter to trace what has power and what doesn't. It could be the circulator is ruined and there's a sensor keeping the test of the unit from operating. You really have to just work your way through the power operations to track down what failed.
So the circulator being ruined could itself be the issue. And by working my way through the power operations, I guess that's in the manual's troubleshooting section. I'll take a look. Thank you!
 

Fitter30

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Pump doesn't come on till the compressor contactor pulls in. R to C 24vac
Y to C 24 vac
Lock in relay
2 to C 24vac. Brn wire
1 to C 24vac Brn wire

Icm220 relay unit Power Off
Pull brn wire off terminal 2
Lock in relay terminal 1 Brn wire
Ohm or continuity between the two brown wires
 

Bgard

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I would suspect that there is a high pressure cutout switch on the high side of the refrigeration circui, by stopping the water flow through the unit the refrigerant pressure would climb very guickly and trip the HPCO switch. Shown in wiring diagram,on the right side midway down.
 

Fitter30

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Three fuses in the compressor box Earth loop protection 2a and WH1 & WH2 5a. Put a volt meter across each fuse if it reads voltage its bad with voltage on. Three low voltage terminal blocks TB1 first and last terminals 24 vac, TB2 first and last terminals 24vac, TB3 across the two terminals 24vac. Have power and good fuses?
Set thermostat to cooling below room temp. TB1 meter lead to C start at R with the other lead. Keep one lead on C move the other lead down each terminal noting what has power on it.
 
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BobD777

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I would suspect that there is a high pressure cutout switch on the high side of the refrigeration circui, by stopping the water flow through the unit the refrigerant pressure would climb very guickly and trip the HPCO switch. Shown in wiring diagram,on the right side midway down.
Bgard-- You have really made my night (understatement).
I've had so much on my plate, and after yet another winter with cold floors, I finally took a few minutes to try your recommendation. I looked up the location of the high-pressure switch in the manual and online and pretty easily located it. When I pressed it and it clicked, I had a feeling that something good was happening. I then turned on the unit, and voila—it powered right up for the first time in almost TWO years and is creating warm water!!! You nailed it.

You guys are the best. Thank you @Bgard and @Fitter30 and @John Gayewski for taking the time to read and respond to this issue. So very satisfying. :)
 
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