my APEC reverse osmosis system just stopped making water completely. the tank is empty. help?

Diagnosis

When an APEC ROES-50 system stops producing water entirely and the storage tank is empty, the root cause is typically a complete failure of water flow into the membrane housing or a catastrophic failure of the auto-shutoff valve (ASOV). Because the ROES-50 relies on osmotic pressure, any restriction in the feed line or a failure in the pressure-sensing mechanism will halt production. If the tank is empty but no water is flowing from the faucet, the system is likely "stuck" in a shut-off state or the membrane has become completely fouled/clogged. To confirm the source of the failure, check the waste water line (the small tube leading to the drain). If water is constantly flowing down the drain but the tank is empty, the membrane is likely ruptured or bypassed. If there is absolutely no water flowing to the drain and no water at the faucet, the problem is upstream: either the feed water valve is closed, the pre-filters are completely impacted with sediment, or the ASOV has failed mechanically, tricking the system into thinking the tank is full when it is actually empty.

How to Fix It

Follow these steps in precise order to restore water flow to your ROES-50 system:

1. Verify Feed Water Supply: Locate the saddle valve or dedicated shut-off valve where the system connects to your cold water line. Ensure the handle is turned perpendicular to the pipe (Open). If you have a separate shut-off valve at the base of the system, ensure it is fully open.
2. Inspect the Tank Valve: Locate the blue ball valve on top of the storage tank. The handle must be aligned with the pipe (parallel) to be open. If the handle is perpendicular to the pipe, the tank is isolated, and no water will reach the faucet.
3. Test for Filter Blockage: If the feed valve is open but no water is produced, the sediment filter (Stage 1) may be completely clogged. Close the feed water valve, unscrew the first stage housing using the provided wrench, and check for heavy sludge. If the filter is blackened or brown, replace it immediately.
4. Reset the Auto-Shutoff Valve (ASOV): The ASOV is the small plastic component with four tubes connected to it. Sometimes the internal diaphragm sticks. Gently tap the side of the ASOV with the handle of a screwdriver to dislodge any debris or stuck seals.
5. Check for Air Locks: If you recently changed filters, air may be trapped. Open the RO faucet and leave it open for 2-3 minutes while the feed water is on. This forces air out of the membrane housing and allows the ASOV to trigger correctly.

If That Didn't Work

• Replace the RO Membrane: If you have water flowing to the drain but nothing going into the tank, the TFC membrane (Stage 4) has likely failed or become "scaled" over. Remove the membrane housing cap, pull out the old membrane, and slide in a new APEC-compatible 50 GPD membrane. Ensure the O-rings are lubricated with food-grade silicone grease to prevent leaks.
• Check the Storage Tank Pressure: The tank uses a rubber bladder and compressed air. If the tank feels heavy (full of water) but nothing comes out of the faucet, the bladder may have ruptured or lost its air charge. Use a pressure gauge on the air valve (Schrader valve) at the bottom of the tank. It should read 7-10 psi when empty. Use a bicycle pump to add air if necessary.
• Replace the ASOV: If the system refuses to produce water and the filters are clean, the Auto-Shutoff Valve may have a failed internal seal. Purchase a replacement ASOV and swap the four lines carefully, ensuring each tube is pushed firmly into the quick-connect fittings.
• Verify Incoming Pressure: If your home water pressure has dropped below 40 psi (due to a failing pressure regulator or city maintenance), the ROES-50 will stop producing water. If your pressure is consistently low, you will need to install a permeate pump or a booster pump to force water through the membrane.

Heads Up

• Pressure Warning: Never operate the system if your incoming water pressure exceeds 85 psi; doing so can crack the plastic housings or blow out the ASOV seals. Install a pressure reducing valve if necessary.
• Sanitization: Whenever you open the system to replace the membrane or filters, it is a best practice to sanitize the housings with a diluted bleach solution to prevent biofilm buildup.
• Filter Schedule: To prevent total system shutdowns, replace the three pre-filters every 6 months and the RO membrane every 24 months.
• Leak Detection: After performing any of the fixes above, run the system for 30 minutes and check every connection point with a dry paper towel to detect slow drips.