Friday, December 18, 2020

Day 2, 3, 4 - Athens, TX

Wednesday (Day 2) - Field trip of the day, Camping World in Tyler, TX, located about 45 minutes from here. I wanted to pick up a heated water hose for the RV. I believe the forecast for tonight’s low is 28°F. There is enough additional heat cable to wrap around the pressure regulator and some foam sleeves were included to insulate the regulator itself. 

Just a shot of the new heated hose. It’s supposed to self-regulate but I’ll probably just unplug it in the morning. I also have a small 250watt electric heater running inside the wet bay. I’m not really sure how much it helps keep things from freezing. It is a cheap heater from Walmart and my thought was to add an outlet controlled by a relay from the ESP8266 microprocessor. I will add an ambient temperature sensor and model a thermostat to control the heater. 

Thursday (Day 3) - What’s with this frost!? It did hit 27°F last night so I guess a little bit of frost is to be expected. The furnace ran almost continuously last night and it wasn’t able to keep the living room/kitchen warm. I think it was 64°F this morning. The good part was the dogs didn’t even budge until I came out around 9am. I went into town real quick for a couple of items and when I returned, I dropped off one of my jars of the honeyberry jam to Garrett and Carolyn.

The RV automatically switched back to the heat pump once the outside temperature rose to around 36°F. Apparently, last night while I was having dinner with friends, the system switched from the heat pump to the furnace. This is what it’s designed to do but this is the first time I’ve seen it. Now if only the furnace could put out some heat…

Friday (Day 4)
 - I changed the controller board in the rear A/C unit to fix a communications error being reported on the thermostat. The communications error seems to be fixed. It still doesn't seem to work properly. If I switch it to furnace, the furnace comes on immediately and never turns off no matter what the temperature is set to. If I turn on the air conditioner, it never comes on no matter what the temperature is set to. The temperature sensor plugs into the controller board and according to the specs, it works fine. 

If I look at the specifications for the sensor, the lower the temperature, the higher the resistance. An open circuit will appear to the system as a very low temperature. The system behavior supports this. I.e. at a low temperature, the furnace will come on and the air conditioner never will. If I remove the sensor connector and measure it's resistance, it matches the table within a few percent.

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