I live in Quebec, Canada. I installed a Geothermal system in october 2014, so this is my first winter. My system is a ClimateMaster model TES049AGD02CNNS. It's coupled with an electrical blower model FE4ANF005. I have a single vertical well, 540 feet deep filled with water and 25% Methanol. I use a single Zone system with a single LCD panel (evolution Wifi). The exterior temperature sensor is a little off (it shows -5C when it's really -11C). The tech told me the water of the well is at 44 degres. When they evaluated the house surface they told me I would need a 3.2 tons for the house, I went with a 4 tons system because the price difference was little and the seller told me a 3 tons will overwork a little to heat my house while a 4 tons will be relaxed to heat my house. My house has 46 years old and it's not that well insulated, I have replaced about half of the windows, the other half will need to be replaced in a near future as they are in pretty bad shape. Currently the problem I have it's that the Geothermal system works perfectly for 10hrs to 14 hrs, then suddently it will give a Low Temperature fault and stops working (the error light flashes 4 times). The Geo will stop working for around 10 hrs or so, then begin working normally again. The system worked well november and december, yet end of december we had extreme cold weather (-35C) and then suddently the Geo started failing to work. The technician has replaced the control panel (the one with LCD) and has replaced the motherboard of the GEO, yet I continue to have exactly the same problem. Currently the tech seems a little in despair about what to do (he came 4 times already). So can someone point me towards a solution or have suggestions what to check to find a solution ?? If you need more information about the setup ask me.