croydoncorgi said:(Sort of) true. Yes - they're sold in pairs. But there's little variation in the resistance values, old to new. And the replacements are not actually 'matched pairs' as such, AFAIK.Both sensors need to be changed on these.
Sorry just seen this post again....when there is a demand the pcb checks both ntcs are in range, if either are not the chb will shut down temporarily with no fault indicator and then go through sequence again.