We have a older rheem gas furnace with a honeywell 3300 thermostat. When we turn on the furnace, the pilot comes on, but does not ignite the furnace. However, if you blow on the pilot light, it lights right up. But you have to do this every time. When the temperature in the house gets cold, the furnace does not come back on. We have to turn the furnace off, turn it back on and blow on the pilot light. Any suggestions?