My hose control unit Moddel 21005 makes an annoying noise when it turns on in the morning. Is this due to something dirty or corrosion inside? Or must I replace the unit? Or can it be cleaned?
If it’s a sound like a small machine gun, then it is probably the valve having a hard time fully opening with the water pressure behind it. This is mostly likely a dying battery. Try putting fresh batteries in. Hope that helps!