How to Replace a Condensate Overflow Switch on a Central Air Conditioning System


If your central air conditioning system won't turn on, there is a possibility the condensate overflow switch has failed and needs replacing. Fortunately, replacing this switch is simple and the part only costs a few dollars in most cases. Below is what you need to know about the functioning of the switch and how you can replace it:

What the condensate overflow switch does and why it's necessary

Central air conditioning systems remove a significant amount of water from a home's air on a daily basis, and this condensate is drained from the system through a network of pipes. If the condensate drain system becomes blocked, it can permit gallons of water to back-up and overflow; the end result can be expensive water damage that costs homeowners hundreds or even thousands of dollars.

That's why a condensate overflow switch is so critical to the proper functioning of an air conditioning system. It automatically cuts off the system should it detect high water levels in the condensate drain. Unfortunately, a condensate overflow switch can fail and should be suspected if the air conditioner won't turn on but appears to be in otherwise working order.

Tools and materials needed for replacing the switch

  • Replacement condensate overflow switch. Check system documentation to determine an appropriate replacement switch.
  • Screwdriver and nutdriver set
  • Flashlight
  • Digital camera
  • Cable ties

Step-by-step procedure for replacing the switch

1. Protect yourself from electrical shock—Before performing any work on an air conditioning system, it is important to disconnect electrical power. Locate the relevant circuit breaker switch in your home's main electrical panel and flip it to the 'off' position before beginning. Do not rely on simply turning off the thermostat as the system may still carry a dangerous charge.

2. Locate the condensate overflow switch—Once the power is safely disconnected, find the condensate overflow switch by tracing the condensate drain back into the air handler. The switch will be contained inside an upright extension of PVC pipe; two wires will lead from the switch into the unit.

3. Remove the system panel cover—The system's main electronics board will be located beneath a panel cover on the air handler. This panel cover can be removed by either unscrewing small hex-head screws, or it may simply slide up and off the unit. Either way, remove the panel cover and set it aside.

4. Identify where the condensate overflow switch connects to the electronics board—Follow the wiring from the condensate overflow switch as it leads down and into the unit. One of the wires will be connected to a main power terminal, and the other will be connected to the system's 'R' terminal. Once you locate these terminals and their connections to the switch, take a digital snapshot of the board for reference when replacing the switch.

5. Remove the defective condensate overflow switch—After locating the connections and taking a picture, unscrew the wiring from the terminals and pull it out of the system's housing. Next, grasp the top of the condensate overflow switch and pull it straight up from the PVC pipe.

6. Install the new condensate overflow switch—Once the old switch is removed, push the new one into the PVC pipe so the float on the bottom of the switch is free to move up and down with the water level. Next, route the two wires from the new switch around the housing and into the system. Attach one wire to the R terminal and the other to a power supply terminal; be sure to reference the photo you took if you aren't sure where the connection should be made. Use cable ties to make the connections snug and neat, then replace the panel cover.

You can always go to websites by HVAC contractors if you run into issues or want a second opinion on the situation.


27 August 2015

Cool off Your AC Bill

Every summer, I agonized over energy bills that would shoot into the stratosphere as a result of my efforts to keep cool in the heat. Every time I turned the temperature down, my bills increased. This summer, I decided to take some of the control over my energy bill back. I installed reflective film on my windows that reduced the amount of light and heat coming into the house. I started serving more cold meals or asking my husband to barbecue outside, so that my air conditioner didn't have to compete with the hot stove, and I started doing laundry at night to reduce appliance heat in the house at peak times. I also had ceiling fans installed. So far, the difference in my bill has been tremendous. This blog is a way for me to explore other ways to reduce energy drain during the summer months.