It seems that a common error code on some older Indesit washing machines is error code 7. This code can show itself as F07. Some models don’t have a digital display though. So washing machines that have a rotating control dial will instead flash the door lock light in cycles of 7 flashes.
As Indesit and Hotpoint are made by the same company some Hotpoint models also use this error code (WF and WD models).
This error code usually means, “heater relay stuck”. The heating element is switched on via a relay. The relay is built into the main PCB. This relay is known to get jammed, causing error code 7.
In my experience this has usually meant a new PCB needed fitting. But as the PCB replacement comes without the main processor (EEPROM chip) one of those is also needed. It’s always possible for a connection fault to cause error codes but the heater relay is embedded in the PCB and if it develops a fault the whole board needs replacing.
I don’t recommend replacing the PCB as a DIY repair. It is an expensive part and it will not be guaranteed unless fitted by an engineer. New PCBs do not come with the micro-chip EEPROM which would also need fitting and programming. Replacing the PCB and EEPROM yourself is risky. If the fault is not cured you cannot send the parts back.
So this repair is likely to be expensive. I have heard anecdotally of engineers freeing off the jammed relay on the PCB by giving it a firm tap.
However, if it’s stuck once there would be a chance the relay could get stuck again later on.
If a washing machine is still under the five-year parts warranty it would be cheaper to let the manufacture fit these parts. Many white goods manufacturers now operate fixed price repairs schemes. It might also be worth checking out the repair options here – Book washing machine (or other appliance) repair.
2: Washing machine stops with lights flashing (General comment on how to decipher error codes manifesting as flashing lights).
3: Program selector knob (dial) clicks round continuously (general advice on error code matters manifesting as rotating control knobs).