For a few bucks more...
you can install an Engine Terminator in the same port (inlet port) and simply wire it to the key switch on the engine. (Instructions included)
As most know - when the machine is running without the trigger being pulled, unless it is being by-passed back to a large holding tank, the un-used water is making a "closed loop" from the by-pass side of the unloader back into the inlet side of the pump. This "short run" of water generates friction, which, in turn, generates heat. Within 4-5 minutes the water temperature will start to damage the packings and brass inside the head.
A few years back we decided that people shouldn't have to keep rebuilding pumps simply because they left the water in "by-pass" to long and so we invented a simple device called the Engine Terminator. Now when the pump head reaches 140-145 degrees the engine simply shuts down and now packings are only replace as they wear out naturally instead of when they are being "smoked" by high temperatures.
Who does this help? You! Who does this hurt? The pump companies and us because we just do not sell many packings to people with engine terminators.
NOTE:
The recommended head temperatures that manufacturers like not to exceed are:
Small Frame Pump – 140-150 degrees (these pumps weigh between 18-20 lbs.)
Large Frame Pumps – 150 – 160 degrees (these pumps weigh between 30-45 lbs.)
Check with your manufacturer for exacts.