How to remove bottom water spin tree. What to remove rotating horizontal arm to get to centre hob below to tighten fixing screws on same. Thank you for your help. David Egan

Question edited for clarity and typos.
Please include full 'make model (what it is)' as first 3 words.

Commercial or Residential?

Residential dishwashers have two filters, a top one that everyone see and rinses out, but these is a much finer one below that in the sump that protects the pump and is where all the very fine fluff collects. No one knows where this fluff comes from, but it is fine enough to severely reduce water flow.

Or the spray bars are blocked. They should be removed every month and checked for obstructions like lemon pips and apple stalks and cocktail sticks. Once again, no one knows where they come from. :>) Remove the arms, (top and bottom, wash and rinse) visually inspect the holes and push debris to the inside. Then flush water in whilst tilting the arm left and right of centre so the bits come out of the main central fixing hole. Then run water down the fixing hole and check it is coming out of the washing jet holes. The ones on the end provide the rotation, which brings me to...

Make sure the arms rotate freely, check before you remove them. They aren't motorized, they work by the water flow pushing them. They should spin at least a couple of revolutions with a good push.

Finally, water softness, descaling, detergent and rinse aid are all important. The machine has to be clean before you start washing, food and food debris should be removed and preferably given a quick rinse before being stacked in the dishwasher.

My expertise is large conveyor dishwashers and smaller scale commercial dishwashers.

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water coming out of horizontal holes is not enough to rotate arms remove them and check the outermost holes these are angled so they rotate the arms they will be blocked even though all the others are clear.

• First, check water level. Start machine, wait until the machine begins main wash. Open the door, the water level should be just below the heater element. If too low replace inlet valve.

• If you can't hear the wash motor running or is just humming, the motor may be bad.

• To check if the food chopper is blocked or broken;

1. Remove lower spray arm by holding the arm and rotating the spray arm retainer.
2. In the back of the tub, unclip or remove the screw from the upper spray arm supply tube.
3. Rotate the lower spray arm support to the right while disconnecting the supply tube from it.
4. Remove the four torx screws from the sump cover, remove assembly.
5. There may be a primary filter in the left side of the sump, if so, remove the torx screw and the filter.
6. On the right side there is the chopper assembly cover. Remove the torx screw and cover to expose the chopper.

Hope everything goes well for you,

Regards

Richard

The problem is likely that the cutter/chopper filter is plugged. This reduces or eliminates water flow to the cleaning arms.
Solution:
Remove dish baskets
Remove bottom arm - Rotate the centre post until arm is free to be lifted out.
Remove conduit to top arm(s) - Remove 2 screws, one at top and one at back. Rotate whole conduit 45 deg right and lift off of centre post.
Remove bottom plastic assembly. - Remove 4 screws and lift off.
Remove cutter cap. - Remove 1 screw at front left. Lift off plastic cap. Remove cutter filter. It is on a spring loaded pin. Pull cutter blade foreword and lift filter disc straight up. Clean filter disc thoroughly
Reassemble!

Possible problem is that the chopper/cutter filter is plugged. This prevents water circulation and therefor no water is available for cleaning.
Solution:
Remove the dish baskets.
Remove the bottom cleaning arm - Rotate the centre post and the arm can then be removed.
Remove the conduit that feeds the upper arm(s) - Remove screws, one at the back and one at the top. Rotate the whole assembly 45 deg right and lift off of the centre post.
Remove 4 screws in the plastic assembly and lift it off of the centre.
Remove 1 screw at left front (Under assembly just removed). Lift off the plastic cap which covers the cutter/chopper. Remove the chopper. It is on a spring loaded pin. Pull the cutter foreword while lifting the filter disc straight up. Thoroughly clean the filter disc - a knife will be req'd to scrape in clean.
Reassemble in reverse to the disassembly steps.

sound like a low water level and or pressure issue. Start machine on normal cycle after filling open door and ck water level. should be up toJUST below heater assy.. assumiong htats good set hte wash arms to a set positon so you can watch for rotation. close the door adn after a few secs open rapidly and look for middle arm to be spinning, even the top 3rd row arm if present, should be spinning spinning . if not its possible that the motor/sumo assy is blocked w/ foriegn debris. remove the lower spray arm (hold the nut and spin arm)then remove 4 or 5 torx 15 screws. probly pretty glogged under there. if not id look into replacing motor sump assy/seals worn and not throwing water where it should go

decrete, you want to get down to the chopper and screen. If the screen is plugged up with gunk there won't be enough pressure to reach the top spray arms. Check out the posted pics. Remove the lower spray arm. Rotate the rear feed arm to the right until it unsnaps from the tube going up the back. See the 4 torq screws holding the filter on. Remove them. Lift the filter up. Now you will see the chopper inlet cover. 1 torq screw holding it in. Lift it up and there's the chopper and screen. Catriver..post back

arms should turn freely. spray arms are only rotated by water spraying out from angled jets at end. check for blockage in spray arms - sweet corn and rice are the worst offenders. take spray arms off and run water in centre hole and see it runs out of all the jets freely

I have the same/similar problem with the upper arms not rotating. After calling a repairman and having him tell me just how lousy LG is (ok, good for future reference) and charging me $100, he told me that the main motor assy. had to be replaced. He wanted $500 to do it! Ouch!! The dishwasher is 2 years old and I was not about to spend that much cash on it. I dove in to it (not literally) and saw that there is a small valve that rotates allowing water to go to only the bottom arm, top arms or both. That valve wasn't rotating when needed and was stuck allowing water to only go to the bottom arm. I set the valve to allow water to all arms, reassembled the unit and it works perfectly. BTW when I calld the repair shop with that information, all they could do was tell me how foolish it is to buy an expensive dishwasher. Hope this helps someone.