The pump overrun on this appliance operates based on temperature when there is no demand from external controls.
The primary heat exchanger on this appliance is cast iron and as a result can contain a lot of latent heat therefore it is possible for the temperature of the appliance to increase even after a demand has ended to a level where pump overrun needs to operate.
If the primary temperature exceeds approximately 82°C the pump will activate to cool the appliance until it reaches a temperature of approximately 70°C.
Depending on the system design and the amount of latent heat held by the heat exchanger after the demand has ended the temperature may not exceed 82°C and therefore pump overrun may not need to operate.
On gravity systems the link setting limits the boilers maximum temperature to approximately 60°C so it is very unlikely pump overrun would ever need to operate so it is unlikely it needs to be tested.
If you want to try and test pump overrun operation then click here.
The primary heat exchanger on this appliance is cast iron and as a result can contain a lot of latent heat therefore it is possible for the temperature of the appliance to increase even after a demand has ended to a level where pump overrun needs to operate.
If the primary temperature exceeds approximately 82°C the pump will activate to cool the appliance until it reaches a temperature of approximately 70°C.
Depending on the system design and the amount of latent heat held by the heat exchanger after the demand has ended the temperature may not exceed 82°C and therefore pump overrun may not need to operate.
On gravity systems the link setting limits the boilers maximum temperature to approximately 60°C so it is very unlikely pump overrun would ever need to operate so it is unlikely it needs to be tested.
If you want to try and test pump overrun operation then click here.