Nests - Error E74

Monitorjak

I have 2 nests installed for different heat pump units. (1 for each unit) and I'm having the same issue with both.
I have the following connected Y1, W1, G, O/B, C, and RH.
It doesn't seem to accept the RH on either. I've used a multimeter and only recorded voltage on the C wire on 1.
The other I only recorded voltage on the RH wire and this one constantly runs the heat out of control. Came home to 100+ temperature Fahrenheit.
Both worked fine for about 5 months. Then my heat pump crashed (27 year old system) shortly after having it replaced the Nest connected stopped working due to no battery charge and my other Nest went crazy.
I have the breaker flipped off for both.
Help Please!

STEVEusaPA

I assume you went to their website for some troubleshooting:
https://nest.com/support/article/Troubleshooting-Nest-Thermostat-power-errors-when-it-gets-cold-outside
Few options:
-Check all the wires and their connections making sure they are properly secure at the Nest and on the unit.
-Check continuity of all wires from Nest to unit-power off.
-Remove C wire, nut it off so it doesn't touch any other wires, flip breaker back on.
-Remove Nest, try charging it with usb cable on computer.
~~and finally~~
Throw nest in trash and get a Honeywell Lyric

iix

I'd do the above and also move that wire from Rh to Rc too some of the smart stats have some strange quirks when it comes to power.