Today I arrived on site Boiler Issue: Responded to a call regarding an E04 error code on the boiler. System Check: Identified the E04 error code on the unit. Resolution: Reset the boiler. The system is now back up and running. Zone: The boiler supports the heating system for the entire house. When arriving at the client's property. The client was not on the property. Moments later the client arrived at the proposal. I proceeded to verify the system. I found the unit in lockout. I proceeded to check the high limited temperature switch. Reset unit, the unit began to operate normally. I showed him and explained to the client about the system situation. I also found the 1st floor area not heating. Bleed the waterline of this area. The 1st floor area began to heat up. I also offered and told him about our service contract. The client said to send him the estimate to let us know. I recommended the client to schedule the appointment to do the system tuneups. The client said he wi