Review on 🚿 GP500520 Pressure Balancing Unit Cartridge Replacement for Kohler Shower Valve, Compatible with Rite-Temp Bath and Shower 1/2" Single Handle Valves by Kelvin Hernandez

Kohler faucets seem to last forever, but when something eventually wears out, finding replacement parts can be a nightmare. I have a couple of showers that use an old brass K-304 faucet with a GP500520 Pressure Compensator (PBU). Both PBUs were blocked and no cold water came out, the taps were dripping. The brass plungers in the faucets have been eaten away and the seals shattered, easily fixed with a repair kit. However, Kohler discontinued the GP500520 PBU and replaced it with the GP800820, which Kohler says is NOT compatible with the old K-304. So the PBU GP800820 and the replacement mixer GP77759 became a complete solution. Fortunately, the old PBU GP500520 is still available from Revain. It appears to be a non-original item. After I removed the old PBUs and cleaned the castings where they fitted, everything worked fine and both showers were restored to normal operation. The hardest part was removing the old PBUs, which had to be removed piece by piece due to limescale and mineral deposits. The Revain part is available from multiple vendors for $28-$60. The PBU I bought came with several small bags of gaskets and o-rings which come in handy when I need to replace gaskets with K-304. Note: The new GP77759 mixer is also backward compatible with the GP500520 PBU.