On 12/01/2017 14:46, RobertL wrote:
On Monday, January 9, 2017 at 9:54:42 PM UTC, John Rumm wrote:


The only bit I am not sure off (since I have never tried it) is what
happens if you have mains on the valve, but then the current from the
thermocouple is withdrawn. That would close the pilot part of the valve,
but I don't know what it would do to the main burner. I am guessing it
would have no effect.

That can't be right can it? Surely if the pilot goes out then all gas must be stopped regardless of whether there is 240V or 0V on the valve.


Indeed. AIUI, when the thermocouple is hot it holds the pilot valve open
and 'enables' the main valve in some way. It clearly wouldn't be safe
for the main burner to be discharging gas just because the valve is
receiving a 240v demand unless the pilot is also on.

See https://www.youtube.com/watch?v=DLxhKrSEDwE for sort of explanation
- American, but I guess their valves were similar to ours.
--
Cheers,
Roger
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