I believe that the 'Platinum" series are discontinued. The automatic 1100 Rule, uses a water sensing technology, rather than a float switch. This tends to give a fairly high "parasitic" drain on the battery. It is not unusual for that switch to fail.
The auto or float switch is the weakest link in any automatic bilge pump.
There are a number of after market bilge pump switches. Water Witch, Johnson Pump Ultima, Ultra Safety systems and Sure Ball. All of these have good reviews.
Here is a Practical Sailer article on bilge pumps.
Here is another one which goes more into the switches.
I have two bilge pumps, in the cockpit area--one is the standard auto type, and the second has an alarm, along with a higher capacity--it is mounted 4" higher up in the boat.
The float switches tend to jam, or break down. But on many occasions the loss of function, is due to corroded leads to the pump. Be sure and use proper marine crimps, using a ratcheting crimper, and the fitting has adhesive shrink wrap as part of the insulation. I also put a second piece of adhesive shrink wrap over the connection (butt connection, from 12 V positive, and ground (12 volt neg.). The ground is often overlooked, but it is just as important as the positive lead.