My Bosch Dishwasher SHU5305UC/U12 suddenly has no wash pressure from the circulation pump. Just a trickle from the lower arms, with arms removed maybe 1-2" of head from the outlet tube on the floor of the dishwasher.
I was hoping to preemptively order some parts for this before doing the major exploritory dismantle, but I am a little stumped as to what is causing this based on the circumstantial evidence I have. Stuff I know so far:
• very little pressure/flow from the circulation system.
• Reached into circulation pump inlet and found no blockages
• put a socket on the circulation impeller and it turns freely.
• Circulation pump motor reads 10.8 ohms at the control board.
• Circulation pump motor is drawing 1-1.1 amps.
• water heater had been working in the past, not coming on now, but I assume that is from the circulation flow switch not activating do to low flow?
• Circulation pum seems to run fine under power, but the noise it makes is different from before. I can't tell if this is pump cavitation do to a blockage, or something else. The motor does turn freely with a socket and I couldn't feel any dragging, scraping, bad bearings etc.
My guesses at this point without dismantaling and actualy looking at the thing are:
Missing/broken impeller vanes?
Some kind of blockage between the pump and the outlet. Is it possible to have a blockage there, it seems like it is just the heater module and pretty wide open space.