ACV Knob for thermostat 54764021

The ACV Knob for thermostat 54764021 is a genuine replacement knob designed for use with ACV Prestige Solo MK1 Smart E 130 and HeatMaster 45 TC boilers. It serves as the user interface for adjusting the setpoint temperature on the thermostat, fitting onto the thermostat's spindle or potentiometer shaft. This knob is part of the ACV White Line range, featuring a white cosmetic finish for visual consistency with matching series. It is intended to replace a missing or damaged knob to restore proper temperature adjustment functionality.

When selecting a replacement knob of this type, verify that the bore diameter, spline pattern, and fixing method (e.g., grub screw or push-fit) match the original thermostat shaft. Measure the shaft dimensions and compare the knob's internal profile to ensure a secure fit. Confirm the fixing method aligns with the existing thermostat design to avoid installation issues.

Common failure modes for thermostat knobs include cracking, stripping of the spline, or loss of the grub screw, leading to loose or non-functional adjustment. Symptoms on the equipment include difficulty turning the knob, the knob spinning without changing temperature, or the knob falling off. Inspect the knob for physical damage and ensure it is securely attached to the shaft.