Not so lovely. Common problems and the newest way to fix the sprayer head.
Turns out soaking it in vinegar for two hours straight did nothing. The sprayer head needs high pressure water to force whatever is clogging it to come out.
*WARNING TRY THIS BEFORE YOU DISMANTLE TO INSPECT PUMP DRIVE SHAFT*
Pump CAN freeze up but this newer version manufactured maybe have fixed that issue.
The most COMMON issue is simply the hand piece clogging up NOT the pump inside the unit.
Catch this problem EARLY and you wont burn out the pump.
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https://www.youtube.com/watch?v=fBkwojkx-Fk