Replacing an air to air exchanger is a relatively easy project. The units tend to be quite heavy, so this is definitely a two-person job. An air exchanger, properly sized, will replace the air in your house a total of at least 6 times in a 24-hour period. Before replacing the exchanger you currently have, ensure that it is the correct size for your home. There are online calculators to assist with this calculation. Look for air exchanger calculators. Also, check all the ductwork around the exchanger.
Step 1 - Measure/Inspect Ductwork
Working with galvanized ductwork can cut your hands, so be sure to wear appropriate work gloves when installing the air to air exchanger. Research the installation of your air to air exchanger. Check your owner’s manual to determine bolt size to make sure you have the correct socket to remove the bolts. Check all ductwork leading into and out of the exchanger and decide on amount of new duct needed to replace any damaged ductwork.
Step 2 - Remove Exchanger
Turn the electricity off to the existing air exchanger (circuit breaker) and unplug the unit. Disconnect the condensate drain tube from the existing air exchanger. Remove the electrical wires from the exchanger. With the help of a friend, first remove the hood and set it aside for re-use. With the socket wrench, remove all the bolts from the exchanger and remove the unit from the ductwork. Dispose of exchanger properly (check local codes or call your garbage collector).
Step 3 - Remove/Replace Ductwork
If replacement is required, remove existing ductwork that is attached to the air to air exchanger. Otherwise, do a thorough inspection (inside and out) and determine if repair necessary. If the ductwork is not repairable, replace with flexible ducting. Since installing flexible ductwork is easy, it is advisable to do so even if it looks okay on inspection. Use duct tape to seal the flexible ductwork at both the new air to air exchanger and at either end of the remaining ductwork.
Step 4 - Install/Replace Hood
If you are re-using the existing hood, it will bolt back easily. You may not be able to find the exact model and size to fit your existing hood. Purchase a model appropriate for your heat exchanger, closest to the same size as the existing materials. It is suggested that you purchase the most efficient exchanger your wallet will allow. Some retrofitting may be required if you are replacing the hood. Ensure that while the ducts are open you bring a professional in to vacuum the system.
Step 5 - Install New Exchanger
Bolt the new exchanger to the ductwork. Place drain tube from the condensation line. Run the tube to a floor drain. Check that all connections are secure. Restore power to the unit at the circuit breaker panel, plug in the air to air exchanger, and turn it on.