Set Appliance State:
| Isolate Mains Power to appliance as per TOPs P4 |
Set Multimeter to Resistance 
CH Demand
DHW Demand
Remove the wires from the right hand L, N, Earth, C and Nc terminals and make safe
Replace the Mains Fuse
Replace the Mains Fuse
| WARNING! - Mains voltage is expected during test follow TOPs P4 live testing procedure |
Measurement:
| Isolate Mains Power to appliance as per TOPs P4 |
Remove the Fuse From Holder
Measure the resistance of the mains fuse.
Isolate as per TOPs P4
and refit as necessary