The DB150 is our only machine that uses a nozzle head shut off valve instead of a control box. Here's how to repair it, if necessary.
You can buy an entire replacement nozzle head shutoff valve, but in most cases, all you will need is the nozzle head shut off repair kit.
Using the nozzle head shut off repair kit
Take apart the nozzle head shutoff valve and identify the worn/broken pieces.
Replace those pieces with new ones from the repair kit.
Refer to the parts list and diagram below to put the nozzle head back together.