O.K. One assumes you are talking about some kind of central heating boiler.
Make? Model?
Precisely what are the symptoms? You know what you mean but we don't have a clue as to the background. Punctuation can make a lot of difference to what other people read:
flashing dhw sensor ?
flashing dhw sensor on the boiler is intermittent?
flashing dhw sensor and the boiler is intermittent?
flashing dhw sensor and the water is intermittently not as hot?
acp, April 2017
