Legacy PTAC Replacement Guide

Before you start

You need a flashlight, a tape measure, and a phone camera. Turn off power to the unit at the breaker or unplug it before you remove the front cover. If the unit is hardwired, have a qualified technician open the electrical connection.

Pick a unit that represents the building. If your property has more than one unit type, such as larger units in corner rooms, check one of each.

Step 1: Read the nameplate

The nameplate is the single most useful piece of information. Remove the front cover. The rating plate is on the chassis, usually on the side panel or near the control box. Some older units also carry a label inside the front cover.

Photograph the whole plate. The model number tells the distributor the original brand, series, cooling capacity, heat type, and voltage. Also record:

• Brand name on the plate, which is sometimes different from the brand on the front cover
• Serial number, which often encodes the build date
• Voltage and amperage ratings
• Heater kW, if listed

If the plate is missing or unreadable, skip ahead. The sleeve measurement and a few photos still get you a match. Read more about finding the model number.

Step 2: Measure the wall sleeve

The sleeve is the metal box built into the wall. The chassis slides into it. Measure the sleeve, not the unit. Units are smaller than their sleeves, and measuring the unit leads to the wrong order.

• Width: inside edge to inside edge, left to right
• Height: inside floor of the sleeve to the inside top
• Depth: from the room-side face of the sleeve to the outdoor grille
• Top shape: flat or sloped

If the measurement is 42 inches wide by 16 inches high, you have the industry standard sleeve. Go to Step 3 with that in mind. Anything else is a legacy size. Legacy sizes still have a replacement path in most cases. Common legacy widths include 32, 36, and 44 inches, and some older installations use a three-piece design with no single sleeve.

Step 3: Check the electrical connection

Look at how the unit gets power.

• Plug and receptacle. Photograph the receptacle. Its shape identifies voltage and amperage. A NEMA 6 receptacle is 208/230V. A NEMA 7 receptacle is 265V. The 15, 20, and 30 amp versions have different blade patterns.
• Hardwired. The cable runs straight into the unit or a junction box. Common on 265V systems and older units. Record the voltage from the nameplate and the breaker size from the panel.

The replacement must match the existing circuit unless you plan electrical work. Electric heat output is limited by the circuit amperage.

Step 4: Identify the heat type

PTAC units heat in one of three ways. The replacement normally matches what you have.

• Electric resistance heat. A heater element inside the unit. The nameplate lists heater kW.
• Heat pump. The compressor reverses to heat the room, with electric backup for the coldest days. The nameplate or model number marks it. Heat pump vs. electric heat for Philadelphia winters.
• Hydronic. A hot water coil connected to the building boiler. You see supply and return pipes, often with valves, connecting under or above the chassis. Note whether the pipes connect at the top or the bottom.

Step 5: Look at the outdoor grille

The grille on the outside wall lets the condenser move air. Look at it from outside, or photograph it from the room side with the chassis pulled.

• Is it a stamped aluminum grille or an architectural louver that matches the building facade?
• Is it bent, clogged, or corroded?
• Does it match the rest of the building? Many owners want the same grille on every unit.

A replacement built for your sleeve normally keeps your grille. Replacing grilles across a facade is a bigger project, and in some neighborhoods it involves design review.

Pick the replacement path

Your five checks point to one of three paths.

Older Trane, Friedrich, Amana, Carrier, and Islandaire units, and discontinued GE Zoneline series, land on one of these paths depending on the sleeve. The sleeve measurement decides it, not the brand on the old unit.

When the sleeve has to go

Most of the time you keep the sleeve. Replace it when:

• The sleeve floor is rusted through and water leaks into the wall
• The sleeve is out of square from settling or damage
• You want to standardize the building on 42 x 16 during a full renovation

Sleeve replacement means wall work, new grilles, and more time with the room out of service. For occupied buildings, a chassis built to the existing sleeve is usually faster and less disruptive.

Send your results

Put your five checks into the quote form. Attach nothing yet. A sales rep follows up for photos if needed.

Units ship to the Philadelphia metro from Louisville, Kentucky, or direct from manufacturer stock. See the service areas.