i have a new Geo installed Oct 2018. In Dec the DXM2 kept locking out. It was due to low temp LT1 code 4. After the jumper was cut, performance has been good. Sufficient heating and now in June, sufficient cooling. I was generating some heat for the HWG in the winter months. As I checked again last week, it appears I’m generating little to no hot water. I also noticed a fault - in test mode I get the same LT1 code 4- low water temp. Are these issues related and why would I have low water temp in June, especially with the jumper cut? Thanks for any advice.
I’m unsure. External hose temperature on incoming is 5 degree cooler than leaving temp. I suspect around 50 and 55 respectively. Is the best way to check using a ACDU01? If so do you know where I could buy one? Will the code remain until fault is resolved? How warm does incoming need to be?
Do you have Pete's ports installed? If so, just get a digital meat thermometer and stick it in the inlet and outlet sides of the heat exchanger piping to measure temps. If you are running AC with only 50 deg F entering water temperature, the compressor doesn't have to work very hard at all to provide cooling for AC. The hot gas side of the refrigerant that is rejecting the heat is maybe 30 deg F hotter than the leaving water temperature of 55 deg F. You can't make much hot water with 85 deg F refrigerant. As your loop heats up the farther you get into summer with longer AC run times, the more hot (warm) water you will be able to generate.
Do you have a two-way communicating thermostat? I have the same system here is a screen shot system status. You can see my system is generating 114.7 hot water into a 50-gallon holding tank.
Arkie6 is correct. The HWG will produce little if any hot water with an EWT of 50F while cooling. The DXM2 monitors compressor hot gas temperature and entering hot water temperature to justify HWG operation. If there is not enough hot gas the HWG pump will turn off. This prevents the refrigerant circuit from stealing BTUs from your tank and rejecting it to the ground. When put in test mode the DXM2 will report the last fault in memory since last power cycle.
Thank you everyone!! This is a great forum for information!! My next step is to get some accurate measurements and then I'll come back for further support. I'm am concerned that I still have a flashing fault at all times on the DXM2. Maybe I need to power off to see if it resets?
@arkie6 and @geoxne I verified entering water is 63 and leaving water is 69 today. It also appears like it is generating hot water- 15 degree difference in temp on HWG lines. I guess I had to be patient and wait for temps to rise. Last question, my fault light continues to blink for low water temp. Because everything seems normal do I just ignore it?
