LUX digital stat Trane XE80 intermittant problem
I just moved into this house and replaced the original Honeywell analog stat with the LUX programable stat. I used the 2 wire config, since there are only 2 wires from the furnace to the stat. It has been working fine for the last month except on 2 occassions that the furnace did not turn on. This does not happen all the time. When it does happen and I "manually" increase the thermostat the furnace turns on.
Example 1) This morning I noticed the temp was 65 the stat was set to 68, but the heat never came on. When I turned the stat to 69 the heat started. I have it programmed to go to 68 about an hour before I get up.
Example 2) The last time this happened I turned the stat down while the furnace was on. When the temp went below the stat setting the furnace did not turn on. Again I had to manually adjust the stat and everything worked fine, until today.
Should I suspect the stat or the furnace?