Grundfos UP 20-30N Domestic Hot Water Service Pump Circulator, 230v. The UP 20-30N is a stainless steel fixed-speed circulating pump suitable for domestic hot-water systems. The UP 20-30N can be connected to an on/off time switch to save energy. The on/off time switch can switch the pump on/off to limit pump operation to periods when hot water is usually required.