my top arm of my dishwasher wont spin. I've checked all the pipes and channels, there is water coming through the holes but it wont spin. I've hade the thing off in the garden and put a hose pipe on it and it spins, but not when it is connected to the dishwasher
If so - the pressure should be OK - it may be blocked with something - like sweetcorn or peas. Or it could be cross threading and rubbing against the washer type thingy that makes it spin.
The bottom arm is spinning, if i open the door whilst in operation the top arm is always stationary and in the same position whereas the bottom is still spinning. I noticed a plastic washer had disintegrated but doesn't seem to affect the spinning when i turn it round by hand
The top one may be fed by a jet fired into a funnel. Perhaps this is out of line in some way, either by the drawer not being pushed in, or incorrect assembly.
If not I suspect a blockage.
I would run it with a dishwasher cleaner such as Finish (small bottle put upside down in cutlery drawer) or Oust (sachet of powder) in case it is grease and limescale reducing flow
when turned by hand you are putting a sideways force on the arm. when the water jets push it round they use an upward at an angle force to turn it. could the fact that the washer has gone awol mean that there is more friction when water driven 'cos parts are rubbing that shouldn't?
check also nothing touches the arm when it's running, try running the machine empty and take a peek. (check if water is coming out the jet holes.)( also, does the missing washer mean the water is leaking past where it should be so reducing the flow that goes to the arm? )