Worcester Bosch High Limit Thermostat L07-P1022 87161423110

The Worcester Bosch L07-P1022 is a high limit thermostat used across a range of Worcester oil-fired boilers and boilerhouse units. It monitors the temperature of the appliance and interrupts the burner circuit if the set limit is exceeded, protecting the heat exchanger and casing from overheating. It is supplied under Worcester Bosch part number 87161423110 and is listed under the spare part group Thermostats, Thermistors & Sensors.

• The boiler locks out or shuts down once it has been running for a period, then restarts after cooling.
• The overheat cut-out trips repeatedly, even when the flow temperature is set normally.
• Heating and hot water stop without a flame fault or fuel fault being present.
• Temperature control becomes erratic, with the appliance running hotter or cooler than the dial setting suggests.
• The boiler cycles on and off in short bursts rather than holding a steady temperature.

• Check the appliance model and serial plate against the compatibility list below, as the same thermostat body is used across several Boilerhouse and Danesmoor variants.
• Confirm the number printed on the existing thermostat matches 87161423110, 1018053 or ZAMAJ227 before ordering.
• Inspect the thermostat pocket and any sealing washer or gasket at the same time, as these are disturbed during removal and refitting.
• Work on the burner and its controls should be carried out by a competent engineer, with the appliance isolated and the fuel supply shut off.