How to Install a New Heat Pump (Overview with Pictures)
Welcome to our latest Pro-Follow! Last week I spent time with local HVAC specialist Chuck Thompson from County Comfort as he and his crew changed out a heat pump. Chuck was called in because after about 15 years the old heat pump had failed. For this job they installed a new, 15 SEER, 5 ton Bryant heat pump.
Step 1: Disconnect the Old Indoor Unit
To begin, Chuck’s crew needed to remove the old system, and they started by turning off the breaker and disassembling the indoor unit to make it easier to remove.
This is the old coil, and you can see signs of rust.
The old blower was in poor shape as well.
Here’s a look a the old pan.
Pro-Tip: Newer units often feature a fiberglass pan to eliminate the possibility of rust. However, fiberglass pans have a tendency to crack from being exposed to heat over time.
With the innards removed, the old housing was much easier to disconnect from the supply and return vents and the drain line.
The guys were careful to salvage the coolant lines because they’ll be able to reuse them for the new system.
Step 2: Disconnect the Old Outdoor Unit
The outdoor unit was quickly removed by cutting the high-pressure and suction lines, disconnecting the power, and cutting the thermostat wires.
Step 3: Move New Outdoor Unit Into Place
Pro-Tip: Because of increased competition, many manufacturers are including 10 year warranties on standard parts for registered products.
The outdoor unit is elevated off the ground with these four feet.
Step 4: Lay New Pan
The previous indoor unit was suspended with chains, and the new unit will sit on this pan which features small mounts to reduce noise from vibrations and an integrated drain connection.
Chuck used 2×4’s to set the height so that the new indoor unit was in-line with the ductwork.
Step 5: Flush Coolant Lines
The newer system will use R410a coolant (rather than R-22), and Chuck used R-11 to flush the line sets
Step 6: Connect Thermostat Wiring
Back outside, the guys began connecting the outdoor unit, and they started with the thermostat wiring.
Step 7: Connect Power
Next, they fed power through a connector and up through a knock-out.
In the picture below you can see the two terminals side-by-side and the ground connection to the right.
Step 8: Install Filter Dryer and Braze High-Pressure Line
All HVAC coolant lines must be brazed, and Chuck’s team started by installing the filter dryer and the high-pressure line. The filter dryer removes contaminants and moisture.
First, the guys dry fit all the components for the high-pressure line.
Next, they fired up the acetylene torch and prepared the brazing rod.
Pro-Tip: Using the torch to create a 90° bend in the brazing rod makes it easier to maneuver the rod into place.
Step 9: Braze Suction Line
After the high-pressure line, Chuck’s crew brazed the suction line.
Step 10: Size New Indoor Unit
Back inside, Chuck team was measuring the new unit for size and working to ensure the supply and return ductwork would connect properly.
Pro-Tip: Newer units obtain a higher efficiency rating by increasing the number of coils. This means newer units are usually bigger and may not fit in the same location as the old unit.
They ended up needing to trim some of the ductwork, and the picture below some a piece of the pre-insulated ductwork found throughout the home.
Step 11: Install New Indoor Unit
Just like removing the old unit, they removed some components to make it easier to move into place. The picture below shows the new unit butting against the return vent, and you can barely see the piece of sheet metal fitted along the top to narrow the opening to size.
The indoor coils are designed to be installed upright or sideways, and you can see the two different pans for each configuration. The air filter fits into that narrow slot on the right just after the air return.
Pro-Tip: Manufacturers pressurize the coils with Nitrogen to verify there are no leaks, and when you remove the plugs, you can hear the Nitrogen exiting the system.
Next to the coil is the blower that forces air through the supply ductwork.
Step 12: Braze High-Pressure and Suction Lines
At this point, Chuck’s crew used a hand-held, pipe bender to carefully bend the copper lines into place.
Next, they brazed the high-pressure and suction lines, and installed grommets (after the pipes cooled).
Step 13: Evacuate Coolant Lines
Back outside, the guys setup a vacuum pump to evacuate the line set.
They usually let the pump run for at least 15 minutes and target about -30 psi on the suction line. After running the pump, they let the gauges sit to ensure no pinhole leaks are present. After that, they charge the line set with freon according to the manufacturers guidelines.
Pro-Talk: R410A freon is sold under the trademarked name Puron.
Step 14: Connect Drain and Emergency Shut-Off
Next up, Chuck’s team made the PVC connections for the drain line and they installed the emergency shut-off mechanism on the pan.
Step 15: Connect Power
The guys reused the old wiring to connect power to the unit, and unfortunately, I don’t have good pictures of this step.
With all the final connections made, Chucks team turns on the new system and checks to make sure the air temperature difference is within range. Lastly, they use Rubatex to insulate the suction line and aluminum tape to cover any joints (not pictured).
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