I had a plumber install a Navien Combi-Boiler with a tankless water heater a few months ago and I do not have consistent timing on obtaining initial hot water.
Sometimes I will turn on the kitchen faucet or upstairs shower and it will take over 2-3 minutes before i get hot water. The Plumber tells me that this is "normal" and I should expect a delay.
I already paid in several thousand dollars and I do not want to give him any more money. Any advice?