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Bruce Farquhar Bruce Farquhar is offline
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Default How does a thermocouple have enough power to operate a gas valve?

On Sat, 08 Dec 2018 23:07:39 -0000, Rod Speed wrote:



wrote in message
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On 12/8/18 3:36 PM, Rod Speed wrote:


wrote in message
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On 12/8/18 1:39 PM, Davey wrote:
On Sat, 08 Dec 2018 16:41:17 -0000
"Bruce Farquhar" wrote:

On older boilers (furnaces if you're American), when the heating
isn't actually running (eg. the thermostat says the house is warm
enough), there's no power to the boiler, so how does the pilot light
valve stay open with the tiny voltage (40mV?) and current from the
thermocouple?

When I lived in America, I was confused that what Honeywell called a
Thermocouple was actually a bulb and capillary tube.

See:
https://www.amazon.co.uk/Honeywell-Q.../dp/B01H2SOZSK

They do not use the differential metal concept, but rather pressure due
to expanding liquid.



Sorry, not so.

Just because it looks like a bulb and capillary, it's not.

See
https://customer.honeywell.com/en-US...uct.Rank&asc=1


Server Error in '/' Application


Oh well. Clicking on link works OK here. Thunderbird & Firefox on Mac OS X


Does now too, must have just been a short term glitch on the server or
something.


Agreed, no problems here yesterday or today on Opera in Windows 10.