Doing some boiler work, replaced a bad zone valve and added an additional zone, now reconnecting thermostat. It would appear the thermostat (2-wire heat only) is functioning properly as the zone valve opens and end switch makes when you call for heat. However, noticed a hot transformer (24VAC system) smell that I didn't previously; by the way I'm only working with one zone for the moment - the others are temporarily disconnected/closed off for other unrelated additional work. Did some checking and find there's a fluctuating 12 VAC current running through system when stat is plugged into its base and is not calling for heat. Is that normal? When removing stat from base while troubleshooting I get either 0 VAC or 24 VAC....which is what I expected...the only time that 12 VAC seems to show up and the only time the transformer smells hot is when the stat is in its base, the 24-volt system is energized and the stat is not calling for heat. Otherwise, everything seems to function exactly as I would expect it to.
Should I be concerned? If so, any thoughts on what's happening?
Should I be concerned? If so, any thoughts on what's happening?