Gas water heater convenient for maintenance

The invention discloses a gas water heater convenient for maintenance. The gas water heater provided by the invention comprises a shell, a fixed unit, a movable unit, a guide device and a locking device, wherein the movable unit at least comprises a heat exchanger and can be conveniently pushed to a pre-determined working position in the shell according to the direction and position defined by the guide device so as to be locked by the locking device; and when the gas water heater provided by the invention is in a non-working state, the movable unit can be drawn outwards and separated from the shell so as to be cleaned conveniently. According to the invention, daily maintenance can be implemented without removing the entire water heater from the wall; and moreover, the gas water heater disclosed by the invention also has an automatic monitoring function and a function of monitoring the using state, and the water heater is always maintained in a good operation state based on convenience in maintenance.