@Lazy Pelican wrote:
My problem is with the thermostat which ‘inserts’ into the front of the water heater and controls the temp to which water is heated.
Understood re the thermostatic mixer. If you haven’t got one of these it is well worth fitting for the reasons outlined in my previous post.
Regarding the thermostat that ” ‘inserts’ into the front of the water heater ” is this the electric thermostat that limits the temperature when the water heater is using AC mains? This is the only thermostat I’m aware of that fits inside the calorifier. AFAIK there is no thermostat in the calorifier that limits the temperature when using the engine. There is, of course, a thermostat in the engine itself that limits the overall temperature of the engine and coolant but this allows the water to reach something like 85C, pretty hot for domestic hot water (hence the benefits of the thermostatic mixer!).
If it is the electric thermostat that is causing the problems, this should be easy to remove and replace, assuming QL/Volvo can supply a suitable replacement. There should be 2 wires to disconnect/reconnect.