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Author Topic: GE Dishwasher Drain Pump Check Valves  (Read 599 times)

Offline go_hercules

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GE Dishwasher Drain Pump Check Valves
« on: June 25, 2018, 01:02:54 PM »

I have a GE dishwasher model GLD4400N10BB.  The drain pump uses two red rubber flapper check valves.  The old ones were crusty and didn't seat well so i replaced them with new ones.  Like the old ones, the new ones don't seat completely without a little finger pressure.  There is no way they could prevent backflow since water in the drain line is gravity pressure only.  In the attached photo, you can see the light coming through the flapper in the installed position.

Offline scrapiron

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Re: GE Dishwasher Drain Pump Check Valves
« Reply #1 on: June 25, 2018, 01:14:33 PM »
When the wash motor is running in wash mode, it draws water from the sump. Without the check valve in the drain pump inlet, water would also be drawn from the pump and drain hose. The suction created by the wash motor seals the check valve.

Offline go_hercules

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Re: GE Dishwasher Drain Pump Check Valves
« Reply #2 on: June 25, 2018, 02:10:51 PM »
Hi, that makes sense to me.  So the function of the flappers is not really to keep whatever water is left in the drain hose from flowing back?  I ask because of the second flapper located at the discharge outlet of the drain pump which would not be necessary according to the purpose you explained to me.  I should not be concerned then about the "looseness" of the flappers in the rest position then???  Thanks very much for the help.

Offline scrapiron

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Re: GE Dishwasher Drain Pump Check Valves
« Reply #3 on: June 25, 2018, 02:15:53 PM »
Yes, it also prevents back siphoning. The weight of a column of water in the drain hose would close the check valve and prevent the water from returning to the dishwasher. Don't worry about the static seal on the "flappers"
« Last Edit: June 25, 2018, 02:16:56 PM by scrapiron »

Offline go_hercules

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Re: GE Dishwasher Drain Pump Check Valves
« Reply #4 on: June 25, 2018, 04:39:31 PM »
Great, thanks for the info.  One more thing while I'm thinking about it if you don't mind.  The fine filter on this machine is donut shaped and just below the lower spray arm.  It is connected to a rubber tube which is part of the sump.  That tube leads to the discharge side of the drain pump.  So what does that fine filter actually do?  Looks like when the drain pump operates it would push water up through the fine filter.  Besides this connection, the fine filter is otherwise closed.  Thanks.