On Sat, 10 Dec 2011 22:26:53 -0700, Tony Hwang
wrote:



croy wrote:
My new wall heater has a gas valve that is thermostatically
compatible. The most common thermostat for this heater is
called a "microvolt" thermostat. It apparently get its
microvolts from something heated by the pilot light.

What I can't seem to get my head around, is how can such a
small amount of power manage to horse-open the rather high
flow gas valve?

Him
No manual to read? My guess is the micro current triggers power to the
valve coil. Definitely it can't directly control the valve.
Wrong - it most definitely DOES directly control the valve as
microvolr controlled gas appliances are the only ones that will work
with the power out and no batteries required.