I had a problem with my heater cycling on and off every few seconds. I had one outfit come out and try to sell me a new unit. Another claimed it was my thermostat. Someone else said it was a circuit board. Steve at Larson came out and correctly diagnosed the problem and repaired it during his initial inspection. It turned out to be a simple problem that he spotted right away. I have not had the problem since. Because I am writing negative reviews about the other services, I had to compliment Larson. They really know what they are doing.