Because of the frequency of failure of standard surface igniters I thought I'd give the new silicone nitride type which is touted having twice the life span. About 2 months after install the furnace developed an intermittent problem where it wouldn't always fire after the igniter glowed. Sometimes it would cycle three times before the gas valve opened and there was fire. Because the control panel light was single blinking I thought I might have a weak gas valve that was failing. I metered voltage to the gas valve and pressure switch when it did this light up failure (igniter glowed but gas valve wouldn't open. Sure, I foolishly threw some parts at it with no change in symptom. Finally I remembered my experience with gas ovens that would develop the same symptoms. In the case of the ailing ovens the igniters even though they glowed they were the fault of the gas valve not opening. Whala, I switched out the silicone nitride with the standard one and all was well again.