DIAGNOSIS That 26lbs/24hr claim is a theoretical maximum under perfect lab conditions. In real use, the machine's compressor and cooling system need time to recover between batches, especially if the room is warm or the water is warm.
FIX For best continuous output, always start with the coldest water possible (from the fridge). Make sure the room is cool and the machine's vents are unobstructed. After it dumps a batch, give it a 15-20 minute cooldown period before expecting full-speed production again. The ice basket also needs to be emptied regularly; a full basket raises the ambient temp inside the unit.
IF THAT DIDN'T WORK If it's slowing down dramatically even with cold water and cool ambient air, the compressor might be struggling due to low refrigerant or a failing component.
HEADS UP The first batch is always the fastest. Consider the 26lbs figure a "up to" spec, not what you'll get on your kitchen counter in July.