At Wits End. Low Water Flow and Dirty Dishes. Expensive Fix

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Old 11-20-13, 08:53 AM
J
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At Wits End. Low Water Flow and Dirty Dishes. Expensive Fix

Flow in my house is just 3 gpm. My dishwasher will not clean my dishes and I suspect it's because of the low gpm.

I've had a plumber look at the system and he believes there is a restriction in the water line coming from my PRV at the meter. He is wanting $2K to reroute the water line to the house.

This $2K is a lot of money to cure a dirty dishes issue. And there are no guarantees the new line will fix the problem.

Would appreciate feedback on this issue.

Jon
 
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Old 11-20-13, 09:53 AM
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Jon you will need to hear from the pros, but I think that plumber should have checked the pressure in your house. If low he should have checked the PRV. The PRV is directly related to pressure. If he knows the PRV is good, but the pressure in your house is not good, then he would be justified in looking for a blockage somewhere. Maybe he did some of that? Seems to me he should have eliminated the PRV before doing anything else. But maybe the plumbers here will say no.

You can get one of those cheap pressure gauges at Home Depot or other stores and put it on a hose bib or drain somewhere and watch your house pressure.

Iím pretty sure low pressure will cause the dishwasher problems. When I installed my Kitchenaid the requirements were a pressure of at least 20 psi. But if you arenít having problems at other places in the house how do you know itís not the dishwasher itself?

But the plumbers and other gurus can give you good help here.

Good luck!
 
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Old 11-20-13, 11:04 AM
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Thank you zoesdad

I should have mentioned that the PRV is new and the flow rate was tested by the plumber and he said it's OK. I get conflicting flow rate info. Some online posts state 3 gpm is good while the local utility tells me it should be 20 gpm.

I've check the psi at the hot water heater, bathroom tub, and at an outside faucet. The flow rate at the water heater is 3 gpm. At the tub, it's 7 gpm.

Yep, could very well be that the dishwasher is bad. I've had to replace the control panel twice. I hate to buy another if the problem is a low flow rate. So I'm kinda stuck.

Jon
 
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Old 11-20-13, 12:21 PM
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My dishwasher will not clean my dishes and I suspect it's because of the low gpm
.


The DW does not use house pressure to clean the dishes.

The DW fills with water and the internal pump uses that water to spray the dishes clean... Kind of recycles it...

The DW drains then refills again to continue the process several times until the cycle ends..........
 
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Old 11-20-13, 03:18 PM
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A dishwasher, like a washing machine, fills to a certain point before moving onto the next step. Sorta like filling a pot with the faucet only open half way. The pot still fills. It just takes longer.

If everything else in the house is working (showers, washing machine...) but the dishwasher isn't cleaning what makes you suspect the main water supply to the house?
 
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Old 11-21-13, 11:17 AM
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Hi Pilot Dane

I was told by an appliance repair person that my DW uses a timer when filling with water. If so, the low flow of water into the house may mean I'm not getting enough water into the DW, thus the dishes are not being cleaned.

Can anyone tell me how deep the water should be in the DW after it fills? I have a Maytag Model MDB4709AWS1.

Jon
 
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Old 11-21-13, 12:38 PM
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thus the dishes are not being cleaned.
I believe the most complaints I have heard on dishwasher performance were more related to phosphates being removed from dishwasher detergents. My opinions is that 3 to 4 GPM is pretty normal in most kitchens served with 1/2" pipe.

the local utility tells me it should be 20 gpm.
I believe you'd probably have to have a 1" line to get 20 GPM. That would be 5 gallons every 15 seconds!
 
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Old 11-21-13, 02:25 PM
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The fill is not timer based. There is a float inside.......

Whoever is telling you that you need 20 gpm is trying to sell you something...

Im on a well and I only have 5GPM... All my stuff works....
 
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Old 11-21-13, 06:07 PM
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Just look at the dishwasher specification of 20-120 psi. That is a crazy HUGE range in infeed pressure and clearly shows that the machine is not filled based on a timer. The valve opens and remains open until the fill sensor or float says that's enough and the valve is closed. Then the dishwasher's pump takes over and generates the water pressure needed for washing.
 
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Old 12-01-13, 04:24 AM
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Just trying to cover all bases and maybe unrelated. Dishwashers need hot water to clean. If you are far from hwh then run a nearby tap on the samy pipe run till water is very hot. Then start dw.
 
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Old 12-01-13, 04:36 AM
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Jon, please answer the questions asked here. How is your shower? Is that ok? When you say the dishwasher doesn't clean your dishes, what exactly do you mean? Does it run the full cycle and the dishes still come out dirty? Did the dishwasher ever clean the dishes? How long have you been in the house?
 
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Old 12-01-13, 05:32 AM
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Dishwashers I am familiar with use a timer to fill and the float is used as a safety or level high limit.
The wide range of pressure allows for machine to fill to an acceptable level at the lowest pressure and the float will close the solenoid if it fills faster.

I have a pic that shows roughly how much water there should be after a fill in one type of machine but what you can do is first allow the machime to fill normally then mark the water height.
After the machine has emptied pour in a couple of litres of water before you start then allow the machine to fill and then compare the levels.
A dirty inlet strainer could be the problem for a low fill level, especially if there was some recent plumbing done.

You can check the water level but there are several other things that can cause it to not clean correcly.
Hard water, bad circ pump, plugged spray arms, worn spray arm busings..........

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Old 12-01-13, 09:21 AM
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I found this on this blog site link below , for what itís worth (sounds good LOL):

Most dishwashers use a water inlet valve with a electronic solenoid to allow the dishwasher to fill up with water. The dishwasher will use either a Timer or Control board to tell the dishwasher when to fill up with water and for how long to fill up with water. Most dishwashers do not measure how much water is filling up into the dishwasher, instead they fill up with water for a certain amount of time. 60-120 seconds is a common amount of time for a dishwasher to fill up with water, but it will vary depending on the make and model of the dishwasher.
Dishwasher Not Filling With Enough Water


(p.s. I tried to post the 20-120 psi fact as a question a week ago but it kept getting rejected? Guess itís who you know. LOL)
 
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