Our heater is flashing an error code 33. The furnace turns on and off before getting up to the temperature that it is set at. The thermostat loses power completely when this happens, and when it comes back on the letters AC are showing on the display. It then shows the temp and the furnace kicks back on... until this all happens over and over again. We have had 2 out of 4 rollout switches replaced, still waiting on the other two. I would like another opinion on this? Any ideas?

Thanks!