Wood burning stove to underfloor heating setup..?

[devs]

Hi guys, I've lived in my house for just under 3 years. When I purchased it there was a wood burning stove in situ but not installed. This is a piped stove flowing back to the water tank.

I believe that the heat from this should be serving the hot water and also the underfloor heating within the house?

I had the stove fitted a couple of years ago now and I've just noticed to the side of the tank that there is a small boxed unfitted thermostat (same as in the last image). I trust that this should have been fitted at the time the stove was!?

I've had no issues with the setup and have run the fire over winter for the last couple of years. My only observation is with the flow and return that exit the rear of the stove the cold water being fed in reaches the same temp quickly. I expected this to take much longer if it was truly heating the underfloor heating throughout the house?

I just want to ensure that its working effectively and I'm receiving the most efficiency out of any wood burning over the coming winter months. I ideally want it to be providing for the underfloor heating throughout the house if at all possible?

Many thanks