When a high efficiency furnace or air conditioning unit runs, water is produced due to condensation of water vapor. This condensate needs a place to drain off so a mess is not created around the furnace. In most instances, it is simple enough to drain the water using gravity to a hub or floor drain that's nearby. However, in some circumstances, the piping has to go up in order to access to a drain. The laws of gravity do not allow this to happen without a condensate pump.
Things You'll Need
3/4" PVC pipe
Miscellaneous PVC fittings
PVC glue & cleaner
Locate the drain where the condensate will be sent. Install PVC pipe from the drain back to near the furnace. Stop the PVC pipe above the furnace for now until the condensate pump is installed. Anchor the pipe to the ceiling or wall, depending on how it is run. Ensure all PVC joints are cleaned and glued properly so they do not leak.
Figure out where you want to mount your condensate pump. Locate the drain connection on the furnace and connect that using PVC pipe to the inlet port on the condensate pump. The condensate pump will have to be lower than the drain connection because the pump needs to be gravity fed. A trap with a vent has to be installed in this line so that the water drains properly.
Connect the PVC pipe from step 1 to the outlet port of the condensate pump. Secure pipe tightly.
Plug the condensate pump into the nearest electrical outlet. If no outlet is nearby, have an electrician install one or use an extension cord designed to handle the current draw of the pump.
Turn on furnace or air conditioner. The unit should now condensate properly.
Polyethylene tubing can be substituted in lieu of PVC pipe. However, it is prone to kinking, which may cause condensate pump to overflow. The trap has to be installed between the condensate outlet on the furnace and the condensate pump. The vent should extend higher than the condensate outlet on the furnace to prevent water from escaping it.
Improper installation of the condensate pump could result in water damage to your home or building.