Hi, I have a viessmann vitodens 100 condensing combi boiler. It has been fine until now. The water temp. when in the shower fluctuates, warm, then cold then back warm again. It repeats this until shower is turned off. I have metered the boiler temp sensor, and according to the book at 50 degrees should be around 4 k ohms. which it is.
Could it be the heat exchanger?
Dawson
Could it be the heat exchanger?
Dawson