Thermostatic control of an unmanaged energy source to supply hot water cylinder
A woodstove would never be connected to a cylinder in such a fashion.

The only use for the thermostatic valve is to control the output of the hot water tank to the user and a common setting is 46 degrees C.

The hot out pipe of the woodstove should have the combined P&amp;T valve fitted with an expansion pressure vessel to allow for the normal water expansion due to the rise in temperature.

The woodstove manufacturer will normally specify the minimum volume of tank to be used and, most likely, so will the local regulations - perhaps also set by the local fire department.