Is $1,900 to replace furnace control board a fair price?

My furnace didn't run for 6-8 months. After a service, it started working intermittently, mostly only in the morning. When running test diagnoses on my Nest thermostat, the inducer fan kicks on, but no heat, then it shuts off. The board LED shows a healthy heartbeat. I've tried a new cheap thermostat that doesn't require a common wire, and also connected a C wire to the furnace and Nest, but the symptoms persist. There is a somewhat loud sound of water during startup. The furnace randomly works sometimes. I had a previous tech come out for service, and this current tech seemed like a salesman.