Guest
Harold, thanks for the response. The temp is 126 degrees at the water heater and there is no recirculating pump installed. We are only having the hammer in the shower and occasionally in the adjacent grohe vanity faucets. There is not a hammer in any of the other valves in the house. We have checked all toilet seats and have cut off supply to all toilets, the hot and cold supplies to the dishwasher, the washing machine, all other sinks and still have the hammer. We have followed Grohe’s recommendation to change out the stems from ceramic to compression with no success. Does this help? Thanks, Robert.
