You have air coming into the return of pool from filter water goes to then heater and back is out with for 5 days now?

If air is coming into your return vent and water from the filter is passing through the heater but not coming out with force for the past five days, several issues could be causing the problem:

1. Clogged or Dirty Filters: Inspect your pool's filter. If it's clogged with debris or dirt, it can obstruct water flow and reduce pressure in the return line. Clean the filters thoroughly.

2. Air Leak in the System: Check for any air leaks in the plumbing lines, especially near connections and joints. Air leaks can draw air into the system, resulting in reduced water pressure. Seal any leaks you find.

3. Faulty Check Valve: The check valve in the pool's plumbing system prevents water from flowing backward. If the check valve is defective or stuck closed, it can create pressure problems and affect the flow of water from the heater. Check and replace the check valve if necessary.

4. Insufficient Water Level: Ensure the water level in your pool is at the recommended level. If the water level is low, it can cause the pump to suck air, reducing water pressure and flow rate.

5. Damaged or Broken Impeller: The impeller inside the pump generates suction and pushes water through the system. If the impeller is damaged or broken, it can lead to reduced water flow. Check the impeller and replace it if needed.

6. Faulty Pump: If the pool pump itself is malfunctioning, it may not generate enough power to push the water through the system. Check the pump for any mechanical or electrical issues.

7. Overheating Heater: If your heater is overheating, it can cause steam or air pockets to form in the system, affecting the water flow. Ensure proper water flow through the heater and follow the manufacturer's guidelines for operating the heater.

8. Incorrect Valve Settings: Double-check that all the valves in your pool's plumbing system are set correctly. Ensure that the valves are open to allow water to flow through the desired paths.

If the problem persists despite checking all these potential issues, it's recommended to consult with a professional pool technician or contractor. They can conduct further diagnostics and provide expert repair services to resolve the problem.