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mikeavison

LG pump motors fill with water

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Hi

I have an LG washing machine which is about 13 years old now and not required any repairs until today. So I am very pleased with it on the whole.

It is a model WM-14331FD but I think my question would apply to most LG models.

Today the pump stopped working. I got the pump mechanism out and found there were 2 identical pumps, one for emptying the the machine and the other for spraying water back up to the top of the drum during some cycles. I applied power direct to the pumps on the bench and sure enough the emptying one was not working. 

Rather than just buying a new one, I dismantled the pump to see how it had failed. The pumping chamber containing the impeller was clean. However, the motor chamber was full of thick smelly gunge. I cleaned it out and it worked again. I was surprised by the design of the motor since there had been little effort in the design to keep water out of the motor chamber, in fact I think it is designed to let water seep in. I opened the other pump and it also had a lot of filthy black gunge in the motor chamber, though not so much as to stop the pump rotating. You might be thinking how could an electric motor work when full of water, well it it is a brushless design with a permanent magnet rotor and external coil stator. The magnets in the rotor are indeed encapsulated in a waterproof plastic cylender.

So it is plain that what had happened is that dirty water had seeped into the motor chamber and over 13 years dirt and bacteria had concentrated around the rotor and jammed it. 

My questions are:-

  1. Am I correct in thinking the motor chamber in these pumps is supposed to fill with water (perhaps to aid cooling and lubrication)?
  2. Is this a common design feature with other washing machine pumps?
  3. If not, do the (non-existent)  "seals" fail like this very frequently
  4. Can anyone tell me a tried and tested routine for stopping dirt and bacteria from building up in the extraction/recirculation system.

Interesting points:

  1. Although the LG is made in Korea, the pumps were made in Italy type Plaset 63096
  2. Both the small service drain pipe and the recirculation pipe were also crammed with dirt and completely blocked.

Thanks for all your anticipated replies

Mike

 

 

 

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Book washing machine & appliance repairs

Ransom Spares

Note: The links above are needed to help keep this site running, please consider using them.

Hello Mike. Yes most washing machine manufacturers just assemble washing machines from parts made by other companies these days. If you stripped down 10 different brands you'd find almost all parts look virtually identical and come from the same third party manufacturer.

I don't understand what you mean by motor chamber and pump chamber regarding pumps sorry. As far as I'm aware the impeller is attached to the rotor and sealed inside the pump chamber. Water runs into the pump and is forced out through the drain hose opening. Water should not seep past behind the pump impeller onto the rotor and bearing. If it has it's probably due to the seal behind the impeller letting water passed through wear. Water pumps are cheap and not well made these days.

If by any chance there isn't a seal behind / under the impeller then presumably they let water in as long as the bearing and rotor are sealed in. Not a very good design but it's lasted well at 13 years so it can't be that bad :)


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Thanks for your reply Andy. I know it is hard to understand what I mean by motor chamber, at least it would be for me because I have never seen an electric pump designed like these before. I wish I had videoed the repair from start to finish because I couldn't find anything like it on youtube. All the youtubers just threw out the pumps, didn't dismantle them. Anyway after cleaning mine out I re-used them. The bearing is only plastic bush on steel spindle. And indeed this is all that would keep the water out, no additional seal. To describe the pumps a little more, there is an impeller chamber as expected, then there is a plastic disk (with the spindle passing through), on the other side a cylindrical chamber for the permanent magnet rotor, around that there is another chamber with nothing much in it (except crud!). The stator is a coil wound around and through the assembly. The stator does not come in contact with the water/crud inside the 2 motor chambers. Having considered it I am pretty sure the motor chambers are supposed to fill with water and this helps lubricate the bearing as well as cool the motor.Anyway if they fail again, which they probably will, I will video the repair. A new pair would be about £90.  Apart from interest, the reasons I overhauled the pumps instead of replacing them are: speed to get washing again, risk of buying pumps that are not compatible (hassle) and cost.

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