GE dishwasher GTD630PYR3FS draining but not completely

[clavius]

Hi All,

My GE dishwasher, model GTD630PYR3FS, S/N ZT761402B has recently started failing to completely drain at the finish of the cycle. We first noticed that the dishes were not quite drying completely and before long the inside of the tub was starting to look moldy. I removed the strainer at the bottom of the tub and found that there was water standing in the little drain sump where the filter locks into. It is still above the level of the inlet to the drain pump. You can see that in the attached photo. 

This is what I have done thus far:

- disconnected the drain hose to check for obstructions and partial clogs. It appeared clear and I went as far as first blowing air through it and then sucking back through it with a wet vacuum. The small amount of water that the air blew into the drain looked clear and the vacuum drew no debris out. 

- the washer discharges into a rarely used disposal. There is no backup in the drain. When the washer gets to a drain portion of its cycle, the drain motor is clearly running (based on the sound) and I can see a strong solid stream of water discharging into the disposal and continuing down the drain.  

- I check that the routing of the drain hose has not changed and the hose has not moved from where it has been since the washer was installed a few years back. It does not have a separate air gap (the disposal is essentially that), but loops up to above the point where it empties into the disposal as it always has. It is the same drain set up that has been on this washer since it was installed and is the same one the previous washer used for 20+ years. 

- thoroughly cleaned the drain sump at the bottom of the tub and cleaned the course and fine strainers to be completely clean. 

What you see here is after I had vacuumed out all the water, cleaned the strainers and everything else up and ran a single standard cycle with "boost dry". When the cycle was complete, the inside of the washer was still wet and this was what was left in the drain sump. 

A couple of questions please: Is there a check valve or similar device that prevent water from coming back in from the drain line once the drain motor shuts off? Looking at the parts diagram I am not seeing anything obvious, but suppose it could be integral to the drain pump assembly. Is there something else I should be checking or looking at? 

I would appreciate any insight before I go blindly changing parts or whatever. 

Thanks very much!

 

[clavius]

And I neglected to mention: there are no error codes indicated on the control and the machine has all the appearance of working OK otherwise. 

 

Thanks again...

[Alanna Farrell]

It sounds like you've done a thorough job troubleshooting so far—nice work ruling out clogs, hose positioning, and drainage performance. Given that water remains in the sump after a full cycle and the drain motor appears to function properly, one possibility is a failing or stuck check valve (sometimes integrated into the drain pump assembly) that's allowing water to backflow into the dishwasher after draining. Even though it's not clearly labeled on the parts diagram, many GE models do have a flap-style valve either in the drain pump outlet or the drain hose itself near the pump. If that valve is degraded or not sealing fully, it can allow residual water to return once the pump shuts off. You might also consider inspecting the drain hose near the pump for any hidden obstructions or slight kinks that could slow full drainage. If everything checks out and the sump still doesn’t fully empty, replacing the drain pump assembly (which includes the internal valve) may be the next best step.

[clavius]

Thank you very much for taking the time to reply. I will admit, the while I don't claim to be any sort of appliance guru, this has me stumped. I troubleshoot and fix stuff for a living, but this is making me feel kinda stupid. 

So by way of follow up, I looked today and took off the drain hose at the pump outlet. No clogs, free flowing and no sign of anything that looks like check valve or flap type valve. If I look into the pump outlet I can see the vanes of the pump impeller. The motor is clearly running and the impeller working based on the strong flow during the drain cycle.

On this machine it looks like a replacement drain pump is just the motor/impeller assembly, (see photo) the rest of the pump body is part of the bottom of the machine.

I removed the pressure switch from the sump on the thought that maybe it was not telling the control that the sump was empty. There was some scungy stuff on hole where the water would reach the diaphragm so I cleaned that all out. This did not make any real difference. One thing I did note was that the pressure switch seems to not be just a switch. I popped the back off of it and there is a small IC chip on a circuit board in there. I am wondering if that is some sort of timer that tells the pump to run for some amount of time after the water drops below the level of the switch (which is maybe 1.5" above the bottom of the sump) to get the last of the water out of the sump.

My theory is that if that has failed and the pump is shutting off as soon as the level gets below the switch it would leave water in the sump. That is a guess and could be complete nonsense on my part. Anyone know if that's how it works? 

A replacement switch is around 25 bucks, so I may just get one and try it. 

Thanks again!

(Note, the photos are just grabbed off the web someplace, not my actual units)

 

[clavius]

Adding to this saga:
I replaced the pressure switch, and no improvement. I am not really surprised too much but figured it was worth a try. 

So in watching the overall behavior of the machine, I noted the following: When I first start a cycle, the first thing the machine does is run the drain for a short time, I presume to remove any standing water that was dumped in while loading. It seems to me that in the past, this initial drain cycle lasted 10 or maybe 20 seconds (that's a rough guess) before stopping and starting the fill step. What I see now it that drain step is very brief, maybe 2 or 3 seconds before it starts to fill. 

The way I would assume this works is that if there is water actuating the pressure switch, the control would start the drain pump until the switch opens, then run for some fixed time to get the last of the water out. I would think it would do the same at the end of the wash cycle. If the switch is already open, then it just runs through the fixed time.

Anyone know if that's how this is supposed to work? Nothing else makes sense to me but I have been wrong before!

If the pump out time is now much shorter than it should be for some reason, then I think this could be a controls issue. Is there a way to reset or otherwise access any control data? I have tried cutting the power to the machine and restarting as well as putting the control into diagnostic mode. It shows no errors and the power cut did not change anything. 

I do not have any technical data on this machine and can't seem to find any. Can anyone point me to a place to find a tech manual? Any thoughts on what I might be missing?

I appreciate any input. Thanks.

[clavius]

Also, I just realized that I mistyped the model number in the topic line and my first post. I transposed the D and T in the prefix. Sorry about that. The correct model number is :

 

GDT630PYR3FS

 

[dp310ce]

Remove the drain hose at the pump   clamp on a separate drain hose on run up to the sink run it through  a drain cycle if it still not drain properly  replace the pump