Not building heat

BTW
if the temp sensor is NOT in the water, it will NOT measure the temp of the water. It will give try to give you the temp of the air above the water, but it's really lousy at doing that.
So if you have used a stack of adapters to make your sensor "fit" well there yago. fix it.
If you wait long enough, the airwill eventually work it's way out of the standpipe, but that water will be stagnant in there, and the adapters will radiate the heat away faster than had it been inside the intake properly, and no matter what you do, it will always read low..