Upon arrival, technician found water heater not filling up bathtub with hot water. Began diagnosis, checked the breaker and the panel to ensure it is getting the right amount of voltage. Then checked voltage at water heater, also opened up water heater where power is going into it to verify it’s getting the proper voltage; also checked the heating element to make sure it was getting proper voltage. After establishing it was, technician turned temperature up on both thermostats. Water heater now producing enough hot water and tenant is happy with the resolution.