We experienced an issue with our Waterfurnace geothermal system last weekend. I noticed that it was a bit warm Sunday evening. I could see from our smart thermostat that the system had been continuously calling for AC since about noon. After heading into the crawl space, I discovered the unit reporting a low pressure lockout via the flash codes on the system board. I cycled power, but no change. Here's what happens : After cycling power, the electronics boot up, the water starts flowing, you hear a relay click on, but the compressor never fires up, and after a minute or two, the red LED1 flashes error code 3. The yellow LED2 is flashing 2,5, and 7 (system pressure trip, open circuit, open run circuit). Come to think of it, those lights pretty much Flash in that sequence all the time regardless of whether or not the system is showing lockout. Voltages look OK, on the line side of the main compressor relay, but best I can tell by measuring voltage on the relay coil, it never even tries to trigger. I'm pretty handy - I installed the water side of this system (with advice from this forum) when the system was originally put in. It's a pump and dump system fed from the spring that supplies potable water to our house. Any suggestions you guys might have to help resolve this would be very helpful. I left some messages with the company that installed the system about 5 years ago, but they have been as of yet unresponsive. It looks like one of the other companies I've used in the past is now selling WF, so I'll reach out to them next. Thanks! AndrewY
The red LED is the fault flash code. 3 flashes is a Low Pressure. Normally low pressure faults are ignored for 2 minutes at startup unless the low pressure condition was present before the compressor start. This indicates a loss of refrigerant charge. The yellow LED flashes DO NOT indicate faults. It indicates the blower speeds set for fan only, 1st stage and 2nd stage.
I read that the low pressure warning is ignored at startup, so you are saying the compressor never even tries firing up at startup because it detects there's not enough refrigerant pressure? Wouldn't a system losing pressure slowly get worse and worse over time? I don't see anything unexpected in my thermostat logs of calls vs temperature.
Yes. It could also be a bad low pressure switch or bad wire connections. You will need to put gauges on to confirm. The low pressure switch opens (faults) at 40 PSI. A Waterfurnace trained tech armed with an AID Service tool can see the state of the low pressure switch in diagnostics. That would be assuming a slow leak.
Well, the technician came out and apparently the unit is empty of refrigerant... that seems bad! Hopefully this can be resolved without a massive hit on my wallet!
