| Well... I got my multimeter & figured out the basics. If I'm reading it correctly (& I think I am) I'm not getting any voltage from the aquastat end of the burner wire to the gas valve. Everything else in the aquastat (power, thermostat & circulator) is juiced. The zone valves are fine. My multimeter has 3 places to the right of the decimal point (in both AC & DC) so it should read millivolts. Does this mean I need a new aquastat? Like I said in my original post, the burner lit up once then quit never to ignite again. It's a 25 year old boiler system. Is the age of the aquastat a factor? DAS |