I have a Carrier furnace and a Noma programmable thermostat. 1 out of every 10 times the furnace tries to switch on there is nothing happening. If I switch the power off and then back on the furnace immediately comes to life! Any ideas?

Not to insult... but have you checked connections at thermostat and back at furnace where thermostat wires connect.. Sometimes problem like this is just that easy. Sometimes not... check that and then get back to us if needing more help. Good luck.