Grundfos Timer Control For UP15-18SU Pump # 505474 (B) The Grundfos 50574 Timer Control only fits the UP15-18SU circulator pump. May be used alone or with a Aquastat control. Switch modes include "Timer" for normal programmed operation and "On" and "OFF" overrides for manual operation. Clock face plastic cover dust protector. Simple 24 hour programming is in 15 minute ON/OFF increments. GRU-CTL-505474List: $93.00Only $70.00 Grundfos 1/2" Clip-on Aquastat Control 115 volts #595443 (C) Grundfos 1/2" Clip-on Aquastat Control 115 volts #595443, Automatically turns the circulator "OFF" when the line temperature exceeds 105 degrees F. and "ON" when it falls below 85 degrees. Clip-on mount for 1/2" I.D. copper tubing. May be used alone or with timer control. Surface sending design with 1/2" clip-on mount for 5/8" O.D. system piping size (1/2" I.D. copper tubing) Availability: Usually ships the next business day. Grundfos 1/2" Clip-on Aquastat Control 115 volts #595443 (C) GRU-CTL-595443List: $37.00Only $27.00 Grundfos 3/4" Clip-on Aquastat Control 115 volts # 595444 (C) Automatically turns the circulator "OFF" when the line temperature exceeds 105 degrees F. and "ON" when it falls below 85 degrees. Clip-on mount for 3/4" I.D. copper tubing.May be used alone or with timer control. Surface sending design with 3/4" clip-on mount for 7/8" O.D. system piping size (3/4" I.D. copper tubing or 1/2 steel pipe) Availability: Usually ships the next business day. Grundfos 3/4" Clip-on Aquastat Control 115 volts # 595444 (C) GRU-CTL-595444List: $37.00Only $27.00