what brand thermostat ?

Unknown

Here's another serviceperson's nightmare. Got called out another one of those "no heat" call after customer stating the thermostat was replaced with electronic ones. These were connected to the famous taco 572 zone valves. Explained to customers that only electronic thermostat that I know will work are the Erie controls using the resitor on the valve. They don't like the look of it on the wall. Is there any other brand available in short of wiring in insolation relay, etc... Thanks all for your helps and ideas...
Btw, this where a 4 post ( dry contact, end switch) taco zone power head would come in handy !

Empire_2

Is this what you have?

See Attached: