The voltage will fluctuate but it should be higher than 3 6v when it s charging normally.
Thermostat voltage readings.
The nest charging problem has been solved by connecting the c ac common wire from my furnace to the nest.
Repeat the test with the other screw.
If the meter reading shows the input voltage to the water heater the lower thermostat is defective and must be replaced.
The line voltage feeding the furnace to operate the fan blower motor is transformed down to a safer level of 24 volts the gas control valve needs 24 volts to open and after making a series loop through at least one safety device the most basic and mandatory one is an over temperature shut down the power goes up to the thermostat and.
If your thermostat isn t receiving enough power to charge the battery and it falls below 3 6v your thermostat will turn off wi fi.
Nest thermostat update and voltage measurements.
Where does a wall thermostat get its electrical power what voltage level is usually required.
If the thermostat does not respond in this way it is bad and needs to be replaced.
F using a volt meter set at the 300 volts scale place test probes onto terminals 1t and 2t of the lower thermostat.
The reading should be between 110 and 120 volts.
If either test results in a 0 voltage reading the lower thermostat is bad and needs to be replaced.
I have had my nest gen1 for almost 16 months now and i probably could not go back to a regular dumb thermostat given the choice.
While most thermostats use a 24v dc circuit some use different voltage levels and or 120v ac is used by line voltage thermostats.
This is the current voltage of your thermostat s internal rechargeable battery.
If it isn t the upper thermostat is not sending power to the lower one.
Line voltage thermostats line voltage thermostats are typically used for radiant convection or resistance heaters that are powered by electricity.
A thermostat with nc contacts should open eventually and the reading on the lcd should swing from 0 00 ohms to ol a thermostat with no contacts should eventually close and the lcd readout should swing from ol to 0 00 ohms.
Also you will use a line voltage stat for cove heaters and in ceiling radiant heat.
Replace the upper thermostat.
