A pump system for use with a solar collector system which is used to heat a heat transfer fluid, includes a storage tank and the pump system having a first and second pump arranged in parallel which can pump the heat transfer fluid from the storage tank to a solar collector, so that should one pump fail the other pump can function, wherein the outlet of the first pump and the outlet of the second pump are connected to a valve arrangement, whereby when the first pump operates the outlet of the second pump is substantially closed by the flow from the first pump and when the second pump operates the outlet of the first pump is substantially closed by the flow from the second pump.

A motor-driven compressor includes an electric motor driven by a motor driver, which includes a switching element that converts DC voltage from a battery to AC voltage. A control unit controls the switching operation of the switching element. A temperature detector detects the temperature of the switching element. The control unit suspends the switching operation of the switching element when the temperature detected by the temperature detector rises to a temperature threshold. The temperature threshold includes a first temperature threshold, corresponding to a withstand temperature of the switching element, and a second temperature threshold, which is higher than the first temperature threshold. The control unit switches the temperature threshold from the first temperature threshold to the second temperature threshold when the control unit activates a field weakening control that reduces counter electromotive force generated by the electric motor.

A fire fighting system for a fire apparatus includes a fluid system including a pump, a sensor configured to acquire data regarding the fluid system, and a processing circuit. The processing circuit is configured to determine a characteristic of the fluid system based on the data and provide a notification based on the characteristic.

Re-calibrating a bearing system of a compressor includes analyzing environmental data pertaining to a compressor to detect occurrence of a calibration threshold event, and re-calibrating the bearing system based on the detected calibration threshold event by controlling placement of a shaft relative to the bearing system of the compressor.

Re-calibrating a bearing system of a compressor includes analyzing environmental data pertaining to a compressor to detect occurrence of a calibration threshold event, and re-calibrating the bearing system based on the detected calibration threshold event by controlling placement of a shaft relative to the bearing system of the compressor.