Googling tells me it’s “a pilot millivolt system”. I guess the downside of this design is that the pilot* is always lit, consuming a certain amount of fuel. Nea

Googling tells me it’s “a pilot millivolt system”. I guess the downside of this design is that the pilot* is always lit, consuming a certain amount of fuel. Neat old quick start guide for a similar thermostat: http://nebula.wsimg.com/b2bc334b6de3591406ddd01974f01830?AccessKeyId=5F08A6A047671B630469&disposition=0&alloworigin=1 http://nebula.wsimg.com/b2bc334b6de3591406ddd01974f01830?Acc... * pilot is manual piezoelectric; doesn’t require electric power