WHER25 Filter Stage 1: Sediment Pre-Filter
The WHER25 Stage 1 sediment filter (Whirlpool part WHERF) removes particulates above 5 microns that would clog and prematurely foul the RO membrane. Replace every 6-12 months depending on local water turbidity. Signs of exhaustion: reduced flow rate from the dispenser faucet, or a visibly brown/grey filter cartridge at inspection. To replace: shut off the supply saddle valve, open the faucet to depressurize the housing, use the filter wrench (included) to unscrew Stage 1 housing cap, remove the old cartridge, insert the new WHERF cartridge, and hand-tighten the housing cap. Restore supply and flush for 5 minutes.
WHER25 Filter Stage 2 and 3: Carbon Pre-Filters
Stages 2 and 3 are activated carbon block filters that remove chlorine before water contacts the RO membrane. Chlorine degrades TFC (thin-film composite) RO membranes rapidly -- a failed carbon pre-filter can shorten membrane life from 3 years to 6 months. Replace Stages 2 and 3 (part WHERCF) every 12 months. The replacement procedure is identical to the Stage 1 sediment filter using the same housing cap and filter wrench.
WHER25 RO Membrane Replacement
The Whirlpool WHER25 RO membrane (part WHER25 membrane) is a TFC membrane rated to reject 98% of TDS at standard test conditions (77F, 65 PSI feed pressure, 500 mg/L TDS). Replace every 2-3 years. To inspect membrane performance, measure TDS before and after with a TDS meter -- a healthy membrane shows 95%+ rejection. If rejection falls below 85%, replace the membrane even if the replacement interval has not elapsed. Membrane replacement requires disassembling the membrane housing (separate from the filter housings) using the membrane wrench included in the replacement kit.
WHER25 Pressure Tank Maintenance
The 2-gallon pressure tank on the WHER25 should be checked for pressure annually. With the system depressurized (faucet open until flow stops), measure the tank air charge via the Schrader valve on the tank bottom. Correct pre-charge pressure is 7 PSI. If below 7 PSI, add air using a standard bicycle tire pump. A tank with zero air charge will fill completely with water and deliver very slow flow from the faucet -- this is the most common performance complaint on WHER25 systems and is resolved by re-charging the tank to 7 PSI.
Cooler Reservoir Cleaning (WFC-1001 and WC18BEK)
Clean the Whirlpool cooler dispensing reservoirs every 6 months to prevent biofilm accumulation. Disconnect power. Remove the bottle. On WFC-1001, use the drain plug at the back to empty both hot and cold reservoirs completely. On WC18BEK, use the drain valves accessible from the rear panel. Flush each reservoir with a solution of 1 tablespoon food-grade sodium hypochlorite (unscented bleach) per gallon of water. Allow to soak 30 minutes, drain completely, and flush with fresh water three times before reloading the bottle and reconnecting power. Allow 45 minutes for temperature recovery before dispensing.