Oversized Heat Pump Gets Replaced by a Properly Sized Heat Pump Replacement in Unicoi, TN

Received a call from an existing customer in Unicoi, TN in need of a heat pump replacement in their rental unit while the property was in between tenants. The previous unit was an older R22 heat pump that was oversized for the living space. The previous unit was a 2.5 ton heat pump and we went back with a 1.5 ton 15.2 SEER2 Daikin split system heat pump in its place after verifying the ductwork sizing and the living space being cooled and heated. The more energy efficient Daikin even though it is 1 ton smaller will lower energy consumption as well as lower indoor humidity levels, which will increase comfort. The previous heat pump was utilizing a 30 amp double pole breaker and a 60 amp double pole breaker. The new Daikin unit utilizes a 15 amp double pole breaker and a 50 amp double pole breaker.

The old setup on the indoor unit would not fit the new Daikin indoor unit so we decided to turn the unit and abandon the tiny door that was previously being used as access for this new system. The new service access will be via a large louver door in the front of the indoor unit and another louver door in the rear for any future access needs. A new return grille had to be installed in the living room wall because the previous return grille was drawing return air from the bathroom (believe it or not). A new return plenum had to be set in place inside an emergency drain pan we installed and a custom fabricated return transition tied the return grille and return plenum together. A custom fabricated supply transition and supply plenum had to be built for this job as well in order to tie the supply side of the system into the supply trunk duct. The old setup was not correct and would not allow the unit to function within factory specifications.

We installed a main line float switch in the primary drain line, an auxiliary drain float switch, an emergency drain pan float switch, a wet switch inside the emergency pan, and we even tied the condensate pump which sits inside the emergency pan with a float switch into the circuit as well. We believe in having redundant backups for water protection in order to better protect a home from potential water damage by the HVAC system. We insulated both lines of the copper lineset with Armaflex insulation to help increase energy efficiency and to better protect the living space from nuisance sweating.

We installed new service disconnects with fuses to match up with our lower maximum overcurrent protections of the indoor and outdoor unit. We even used a surge protection device on the indoor service disconnect to help protect the ECM blower motor from power surges or damage in the future. We placed the return plenum inside the emergency pan on 6 pump ups with anti-vibration pads to help isolate vibration and noise. We insulated the return plenum transition and supply plenum transition with 3" foil faced R8 insulation to help with noise and potential sweating on the supply side of the system.

We leveled out a new larger pad outside and lifted the outdoor unit on pump-ups and anti-vibration pads to help keep the outdoor unit cleaner in between maintenances and to assist with drainage and to prevent snow accumulation during the winter months. We insulated the outdoor lineset with special UV resistant 3/4" wall K-flex insulation that will resist sun exposure longer over time and secured it to the building. We always make sure to seal up any penetration into the building envelope with silicone to help prevent water intrusion into the home as well.

We performed 2 pressure tests on the equipment with dry nitrogen and both passed. We pulled a deep vacuum down to 147 microns and the vacuum passed the decay test with zero rate of rise so we know that we had a dry and tight system. We performed a static pressure test on the system's ductwork and confirmed that our total external static pressure (TESP) did not exceed the manufacturer's maximum allowable design parameters. We dialed in our blower speed based on the TESP so that we could fine tune the air delivery of our system. We also set up our defrost settings to best match our system's location so that it can operate at its best during the winter months.

We tested the refrigerant detection/mitigation system as well as the refrigerant sensor for functionality and confirmed that both were working properly. We tested each float switch individually as well as the wet switch to confirm that they were shutting down the system as designed if any one of them tripped. We trimmed in the refrigerant charge based on our lineset length and sub-cooling values. We logged amp draws on the machine at startup and while it was running as well. We labeled our units inside and outside as well as the breakers with UV resistant labels so that anyone working on this machine in the future would know exactly how it was setup. We attached all of the paperwork relating to this unit to the back side of our indoor air handler.

We tested the system in all of its functions and confirmed its proper operation. We verified with our probes hooked to the system that we had the proper pressures, temperatures, superheat & sub-cooling values, and that we were delivering the proper airflow inside the home as well.

If you are inside of our service area of Northeast Tennessee and you value quality workmanship, please feel free to reach out to Magnolia Services based out of Johnson City, TN. Anyone HVAC contractor out there can throw a piece of equipment in, but if it isn't done right you will have issues in the future that will cost you in a big way. A properly installed piece of equipment will save you on energy costs, provide more comfort inside the home, and cause less headaches down the road. We don't take shortcuts on our jobs and we would be happy to change out your old malfunctioning HVAC equipment with new equipment that is set up properly within its design parameters. Stay safe and best wishes.

Location: Unicoi, TN