Wall Heater Thermostat

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?
--
croy

Add pictures here
<% if( /^image/.test(type) ){ %>
<% } %>
<%-name%>
Add image file
Upload
croy wrote:

No manual to read? My guess is the micro current triggers power to the valve coil. Definitely it can't directly control the valve.
Add pictures here
<% if( /^image/.test(type) ){ %>
<% } %>
<%-name%>
Add image file
Upload
wrote:

microvolr controlled gas appliances are the only ones that will work with the power out and no batteries required.
Add pictures here
<% if( /^image/.test(type) ){ %>
<% } %>
<%-name%>
Add image file
Upload
http://wiki.answers.com/Q/How_do_millivolt_gas_valves_work

Add pictures here
<% if( /^image/.test(type) ){ %>
<% } %>
<%-name%>
Add image file
Upload
On 12/10/2011 10:34 PM, croy wrote:

The something is a thermocouple. It is actually millivolts not microvolts. The common name for that system is "powerpile" which might be a Honeywell trademark. We used to have that system on an old steam boiler. It worked well and as long as the natural gas flowed there were no worries about power outages.

to open it.
Add pictures here
<% if( /^image/.test(type) ){ %>
<% } %>
<%-name%>
Add image file
Upload
On 12/10/2011 10:34 PM, croy wrote:

the valve. The down side is that it generally takes a while to operate, unlike a 24 or 120 volt coil valve
Add pictures here
<% if( /^image/.test(type) ){ %>
<% } %>
<%-name%>
Add image file
Upload

Sounds like it's the same type of system used on most water heaters that also don't have any external power source to open the gas valve.
Add pictures here
<% if( /^image/.test(type) ){ %>
<% } %>
<%-name%>
Add image file
Upload
On 12/11/2011 9:05 AM, snipped-for-privacy@optonline.net wrote:

It is. I don't see them on conventional heating systems anymore. They were great when the power went out. Once the thermostat called for heat, it took a minute or so for the valve to open
Add pictures here
<% if( /^image/.test(type) ){ %>
<% } %>
<%-name%>
Add image file
Upload

HomeOwnersHub.com is a website for homeowners and building and maintenance pros. It is not affiliated with any of the manufacturers or service providers discussed here. All logos and trade names are the property of their respective owners.