Cold

[stek]

Unless the heating comes from an immersion heater it's not the thermocouple.

If it's a combi, could be the diverted valve. If it's not a combi then it's the three way valve, or one of the two ways if it's s plan not y plan.

Have you tried bleeding the radiators?

The hot water could be in the tank from before the thermo failed.

 

[mudskipper]

Combi I think. Valve rings a bell as something that's got stuck in the past. Mr ms will give it a kick in the morning, but given that the fuse blew there might be some electrickery.

 

[suityou01]

Combi I think. Valve rings a bell as something that's got stuck in the past. Mr ms will give it a kick in the morning, but given that the fuse blew there might be some electrickery.

Could be your knuckle-valve-strumbler.

 

[vetran]

Top Tip! fuses don't just blow because they want you to visit them - you need to identify the cause

actually they do.

frequently they blow due to a fault however they can just age or blow during a surge.

http://paris.utdallas.edu/IEEE-RS-ATR/document/2008/2008-12.pdf

Zeity - don't all domestic fuses come from China nowadays?