Plumbing and heating expert Richard Trethewey shows us how to properly maintain a mini-split HVAC unit. Richard explains the maintenance these units require as well as provides some helpful tips for keeping your home dry while still getting a deep clean on all of the unit’s most important parts.

Next, we meet host Kevin O’Connor, general contractor Tom Silva, paint expert Mauro Henrique, and Richard back at the shop for a brand new “What Is It?” After some pretty off-the-wall guesses, Richard shows them exactly what he brought to the table—literally.

Finally, we tag along with mason Mark McCullough and landscape contractor Jenn Nawada for a fun project: Helping a homeowner build a side yard retaining wall topped with a selection of beautiful shrubs. Mark, Jenn, and the homeowner work together to dig a footing, grade the soil, and install a retaining wall from blocks. After installing drainage and backfilling the wall, Jenn and the homeowner installed a range of shrubs to fill in the area.

How to Clean and Maintain Your Mini Split

Mini-splits are a type of air conditioning unit where the two main components are divided into separate parts (an indoor and an outdoor unit), with refrigerant piping connecting them. 77% of the world’s air conditioning market is handled by mini-split. And while they’re simple and efficient, they do require some maintenance. Here’s what you need to know to maintain yours like a professional.

Where to find it?

To clean the indoor unit:

Start by removing the cover. Most models can be disassembled with a screwdriver. Use a bowl or plastic container to collect screws. This will help keep track of all the pieces as you work. With the outer shell off, remove the air filters

To clean the air filters:

Wash in the sink or spray the air filters using a water hose. If the air filters have built up dirt, use a mild liquid soap and soft brush to gently break up the dirt. Rinse thoroughly.

Use a mini-split clean kit to protect the wall from getting wet. Tape plastic sheeting around the electrical components to prevent any damage. With the protect cleaning kit in place, spray on the non-corrosive coil cleaner to the coils of the indoor unit. Remove the coil cleaner with water. You can fill a pump sprayer with water to keep the rinsing contained.

To clean the outdoor unit:

Start by using a vacuum to remove leaves and dirt from the coils. Then spray on the condenser coil cleaning spray. A face mask, eye protection and gloves are recommended when handling coil cleaner. Use a pump sprayer to remove the coil cleaner from the outdoor unit.

What Is It? | Rubber Bouncy Cap

We love our “What Is It?” segments, and it’s not just because we’re featuring a new tool or material. We also love hearing what our crew comes up with. When heating and plumbing expert Richard Trethewey brought small, gray, rubber puck-like objects to the shop, the team’s ideas started to flow.

Where to find it?

Richard brought in anti-vibration pads for quieting washer and dryer machines.

How to Build a Garden Retaining Wall

While the yard sloping away from a home is great for the foundation, but it can create landscaping issues. Severely sloped grades make garden beds look sloppy and bare, especially if there’s a downspout nearby. When a homeowner struggled with her sloped garden, she called mason Mark McCullough and landscape contractor Jenn Nawada for the solution: a garden retaining wall.

Where to find it?

Wall blocks provided by Unilock

Wall Blocks – Unilock’s Concord Wall Smooth

811 “Call Before You Dig” was contacted before any work was done.

Jenn used a long tape measure to figure out the dimensions of the new wall. Then spray paint was used to mark where to dig for the footing of the wall.

Mark used a mini excavator to regrade the garden bed and dig for the wall footing. The machine was used to make the work go by quicker, but shovels can also be used. Wheelbarrows were used to move dirt. Mark dug about 8 inches for the wall footing, but instructions for wall prep may differ based on the wall material manufacturer.

Hand tampers or a compactor can be used to compact the dirt down. About 6-8 inches of clear gravel was added for the wall base. Then a heavy-duty metal rake was used to spread it out.

Mark used two stakes to mark the two corners of the wall. The stakes were used to make sure the wall would be square to the foundation. Then he used string from stake to stake to represent the face of the wall. He used a line level to make sure the string was perfectly level. Then placed two benchmark blocks by each stake, using a torpedo level to make sure they were completely level. He then added a block every 6 feet, using a 6 foot level and mallet to shift the blocks into place.

Heavy duty construction adhesive was used on the corner and cap pieces of the wall.

For the drainage portion of the wall, Mark and Jenn used a 4” perforated pipe wrapped in drainage filter fabric. And downspout adapters to connect the pipe to the downspouts.

Jenn planted:

• Green Mountain Boxwoods
• Delaware Valley White Azaleas
• Little Quickfire Hydrangeas
• Cunningham’s White Rhododendron
• Oakleaf Hydrangea

_{Original Air Date: Apr 10, 2025, Season 23; Ep. 19 23:42}

Products and services from this episode

• Mini-split cleaning kit manufacturer: RectorSeal
• Non-corrosive coil cleaner manufacturer: RectorSeal
• Condenser coil cleaner manufacturer: Nu-Calgon
• Retaining wall concrete blocks manufacturer: Unilock
• Clear gravel manufacturer: Madison Block & Stone