How To Replace A Torn Or Damaged Diaphragm In A Septic System Aeration Pump

If your septic system's aeration pump has stopped working, it is likely the cause is a torn diaphragm. The good news is that replacement of the diaphragm is a simple repair and can be performed by almost anyone using a minimum of tools. Below is more information on diaphragm air pumps and how you can perform this easy fix:

How a diaphragm air pump operates

Air pumps come in several configurations, but the most commonly used air pump for septic system aeration is the diaphragm pump. Diaphragm pumps are elegant in their simplicity of operation; they utilize two opposing rubber diaphragms that move back and forth at a high rate of speed, with the motion powered by an oscillating electromagnet. This motion causes air to be sucked through a one-way diaphragm check valve and pushed out the other side, and this movement of air is reversed when the diaphragms move the opposite direction. No matter the direction, air will be pumped out of one of the diaphragms. The lack of moving parts plus the simplicity of the system means diaphragm air pumps are reliable and operate for years at a time.

However, over time, the diaphragms will eventually wear due to repeated stress, and a tear will ultimately develop in one or both. When this happens, the pump's airtight integrity is eliminated, and it will fail to work at that point.

How to repair a diaphragm air pump

Since there are so few moving parts and the diaphragms are readily visible when the pump case is removed, replacement of the diaphragms is not difficult. Below is how you can perform this replacement:

Tools and materials needed

  • Replacement diaphragms
  • Plastic safety screw
  • Pliers
  • Screwdriver or nutdriver

Step-by-step procedure

1. Unplug the air pump - Even though the air pump may not make any noise, you need to be sure to unplug it before opening the housing. The internal electrical components carry 120 volts AC and can cause a dangerous shock.

2. Remove the housing - Locate the screws on the bottom of the pump that attach the housing to the pump's base. Remove the screws and set them and the housing aside in a safe location.

3. Disconnect the air hoses from each end - The diaphragms are covered by two heads that are clamped to outgoing air hoses. Squeeze the clamps with a pair of pliers, then slide them down the air hoses to remove them. Gently tug the ends of the hoses to pull them free of the heads.

4. Remove the diaphragm heads - Once the hoses are disconnected, remove the diaphragm heads from the pump's mechanism using a screwdriver, and place the screws aside for use later. Inspect the heads carefully for any signs of damage or excessive wear; the one-way check valves inside the heads can become worn and leaky, so be sure to replace them if necessary. Some diaphragm pump rebuild kits come with new heads, and you should always discard the old heads and install new ones in that situation.

5. Remove the diaphragms - After the heads have been removed, take a look at the diaphragms beneath. You will be able to visualize the torn rubber easily. Unscrew the fasteners holding the diaphragms to the pump, then pull the diaphragms out of their mounting locations.

6. Inspect the magnetic rod block - Inside the pump's electromagnet lies the magnetic rod block. This component consists of a powerful permanent magnet that is moved by the electromagnet; to remove it, simply pull on one end of the rod block, and it will slide free from the pump. Next, take a close look at the rod block for signs of cracking or chipping. A damaged rod block will need to be replaced by a new part before proceeding with the diaphragm replacement.

7. Install the new diaphragms and reassemble the pump - Once you have inspected the rod block and ensured it is still in good working condition, you can install the new diaphragms by going in reverse order of the disassembly process. Attach the diaphragms to the pump by reinstalling the fasteners, then attach the heads to the tops of the diaphragms. Reattach the air hoses to the heads by sliding the clamps back over them.

8. Install a new safety screw - The last step before reattaching the housing to the pump base is to install a new safety screw. The safety screw is a plastic screw that holds the internal electrical connectors together; if the diaphragm breaks, the safety screw will also snap and interrupt the current flow, thus preventing the pump from overheating and being ruined. Locate the screw holes in the connectors and insert the new safety screw into them. Tighten the screws until the connectors are snugly attached to each other.

9. Reinstall the housing - Position the housing over the top of the pump base, then reinsert the screws holding the housing in place. Tighten the screws and plug in the pump to test its operation.

If you feel you cannot do this yourself, contact a professional septic service company in your area, like Martin Septic Service Inc.