Replacement Top Hatch Controller The XM18 is our standard Top Hatch controller and has provided reliable service in thousands of incubators over more than twenty years. Many customers are still operating their original controllers today. Current-production controllers incorporate upgraded relay ratings, substantially increasing their tolerance to the modern electrical environment. The remaining high-load circuit is the humidity ("WET") output, which switches both the 2 A AC/DC transformer supplying the ultrasonic humidifier and the 8 W, 240 VAC cooling solenoid pump. For this reason, we strongly recommend fitting the optional Humidity Relay Upgrade (SSR Module) when replacing a controller in an earlier machine. The SSR isolates these loads from the controller, leaving the internal humidity relay to carry only the SSR trigger current. Before ordering a replacement controller, please ensure that: a) The failed controller is an original Greatlander-supplied XM18 and not an imitation or aftermarket substitute.b) The ON/OFF differentials for both temperature and humidity are correctly set so that the relays are not switching excessively.c) Your mains supply voltage remains within the recommended operating range of 220–240 VAC. In some areas, the widespread adoption of rooftop solar has resulted in sustained daytime voltages that exceed this range. Before replacing a relatively new controller, we recommend checking the supply voltage in the morning and again at midday on a sunny day. A simple digital multimeter set to the 500 VAC range is suitable for this test. Measure between the active and neutral conductors of a wall outlet. The measured voltage should normally be between approximately 230 VAC and 240 VAC. Persistent over-voltage conditions can significantly shorten the life of electrical components. Because incubator electronics operate continuously in a warm environment, excess voltage is dissipated as additional heat within the components, accelerating their ageing. If your local supply voltage is consistently above specification, contact your electricity provider, who may be able to rectify the issue. Alternatively, where high voltages cannot be avoided, we recommend operating the incubator through an inexpensive voltage stabiliser or regulator. Important: If the failure involves the humidity circuit, please add the Humidity Relay Upgrade (SSR Module) to your order. The module is supplied pre-wired and ready for installation and provides additional protection for your replacement controller.
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