Sounds like the thermostat went crazy!

You CAN test a thermostat and see if it works correctly
by using a meter and checking so see if the relays are
clicking on and off, but by the sound of it... I'd say
the thermostat is either incorrectly programmed or shot.

Tom


Steve wrote:
I am having a problem with my gas central heating system. I have a
Lux
500 programmable thermostat that I installed a few years ago. When I
came home this evening, my house was extremely hot. The thermostat
display was flashing "OL" which I found out means that the temp is
above 95 degrees. I turned the switch from heat to "off" and the heat
turned off after a few minutes. I removed the cover and changed
batteries. Still, when I click the switch back to heat, the heater
starts up again even though the temp has dropped to 92 and the
setting
is on 68. Do in need to replace the thermostat with a new one, or do
I have another problem?

Thanks,
Steve