it's a small water source heat pump. it worked great for years with the mercury bulb tstat. I upgraded to the digital programmable today, but whenever the compressor contactor is energized, I get a voltage sag, the display drops for a second, and I lose the call for cooling. Compressor is only on for a second.
found the primary tap of the control transformer on the factory setting (230 v) but my mains are 208. switched that. same problem, only stays on maybe a second longer.
when 'jumped out' at stat location unit works fine, and in the control box as well.
no unexpectedly high resistance through my control circuits (but I would expect the transformer to overcurrent and fail if I did anyways)
I'm suspecting that years of running at the wrong voltage (and hence higher currents then rated for) have caused this transformer to 'weaken' and it can't handle the inrush current of energizing the compressor contactor coil. Does this line up with anybody's experience?