To-Do List: Heat Pump System
I'd originally wanted to do the installation, and leave the system charging and testing to a contractor. However, many systems are not available for customers to purchase directly; they can only be obtained through licensed contractors as part of an installation package, which drives up the cost. So, I had to bite the bullet. As of 12 November 2018, all of the ductwork was (re)done. The heat pump blower would be mounted on its side, with the air flow from right to left in this view:
By 21 December 2018, the refrigerant line chase (made from conduit left over from the electric service line) was installed:
By 27 December 2018, the space for the blower was insulated, lined with plywood (to protect the insulation), wired, illuminated, and totally ready.
On Sunday, 30 December 2018, I met with an HVAC contractor. As I anticipated, he predicted there might be problems getting the system running right; the smallest central unit made was slightly too big for my little home. To compensate, I added a bypass to create additional airflow, mostly to keep the coils from freezing up during AC operation. Blower installation was completed on Sunday, 6 January 2019; since I worked from detailed specifications obtained online, it almost literally dropped into place.
I took care of installing the bypass (top two images above), wiring the AC supply and thermostat line (lower left, above), and adding the condensation drain (lower right, above) on 8 January 2019. And the compressor (below) was installed and charged on 13 January 2019.
Because it was only 28° outside at the time, the installers needed to return when it was warmer to get the system property balanced and running correctly. That they were able to get it working at all—when the manufacturer recommends a minimum temperature of 40° for charging—was remarkable. To help the contractor, I installed a thermocouple on the inbound refrigerant line to monitor its temperature. Worked like a charm. Also of note, the refrigerant line chase, which I'd thought would be a benefit, was actually a hindrance, because the refrigerant lines couldn't follow the bends; I had to tear it all out. No biggie—took maybe three minutes.
On Sunday, 27 January 2018, the system was serviced again, although it required another tweak on 10 November 2019 to optimize the heating cycle.