I have a 9 yr old Lennox furnace, propane. 3 zones. The main zone triggers the furnace, ignites, maybe runs 3-5 min then i get the altnernating red/green LEDs fast flash. Code says thats 1) improper ground 2) line voltage below 24 or 3) faulty ignitor. The other 2 zones work just fine which to me indicates the furnace/ignitor blower etc are mechanically OK. Am I maybe dealing with a bad circuit board? I replaced the T-Stat on the bad zone but no change. BTW, if not already obvious I am not highly techinical with this stuff, just like to get as far as I can before pulling the trigger on calling HVAC guy. Really appreciate any help. At least not interupting the NCAA games yet. Rob

 

Hi Rob,

First off, let's make sure this is a HOT WATER BOILER, and NOT a "FURNACE"... we usually call forced hot air systems "furnaces" but hot water systems "Boilers".

Presuming it is a boiler;

How are the zones controlled? Do you have electric zone valves? If so, what make/model?