Home Improvement Questions? Ask a Handyman for Answers ASAP
Hi. did not check.
I will check your suggestion immediately & get back to you.
Thermistor resistance reduces with temperature increase.
I suspect it does as hot water is ejected from the expansion pipe into the header tank.
I suspected the pump but discounted it as it is less than 12 months old & outwardly appears to be moving water. I cannot see why a faulty pump affects the boilers temperature control?