Thank you. I spoke to Taco tech support and all is well. It so happens
that the older Honeywell thermostats don’t care if the red and white are
switched on the relay. Hence the older relays did not have a specific
marking to indicate R and W as power...
Figure 1 shows my pre- nest setup. I have heat only with 2 wires- white
and red.figure 1 shows my pre-nest setup with white on left and red on
right connected to Taco sr502.after nest connected as per figure 2 I get
the code indicating missing c wire...
Thank you. I did a reset on the thermostat after introducing the nest
power connector. However it does not pick up the power. Once I removed
the power connector it is picking up power now. But then back to the
code for the missing C wire
Same issue with me- i hooked up the nest power connector on the Taco
SR502 and the thermostat just says no power. I removed the nest power
connector and the message goes away- power is now available but says C
wire is missing. Wonder if anyone resolv...