Installing A Warp Switch

flashheatingand

I don't know if this has happened to others or not, but, I thought I would share this. Yesterday upon a no heat call (Carrier furnace 80% mfg. date '91) determined the warp switch was the culprit. Replaced the switch, checked the heat and all was well. One hour later, I got a call from the home owner...No Heat, and a strange smell from the stat and ignitor is making a different sound.

Upon arrival, I disconnected the t-stat, checked out things to find the spark box was clicking but no spark. Checked voltage in ...good, voltage out...nothing. Called our local supplier for any advise and was told the spark box was bad.

I thought hmm, how could installing a new warp switch damage a spark box, checked the wiring and all. It all looked good, so I ran to the supply house picked up a new box. Returned and that empty feeling arose when the same results occured.

At that point, I looked at the warp switch and noticed that it was in direct contact with the adjacent burner. As a result, I was creating a direct short from hot to ground.

This fried the t-stat, and I ended up purchasing a spark board when it was unnecessary. Not a profitable job, but a experience to remember. I just thought I would share this just in case someone else may have to replace a warp switch in the future.