washer: adjust inlet valve for low water pressure?


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Old 08-01-06, 05:36 PM
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washer: adjust inlet valve for low water pressure?

I'm trying to make use of vast amounts of rainwater by connecting my washing maching to a rainwater tank. The trouble is the inlet valve (aka "mixing valve" "flow valve" or "solenoid valve") on the washing machine.
The tank is in the yard about 6' in elevation above the washer, so there is plenty of pressure if I simply manually hold a hose from the tank into the washer to fill it up.
But if I connect the rainwater tank's hose directly to the inlet valve, all I get is a tiny trickle, because the inlet valve is built for the much higher pressure of household water.
I've checked with the washing machine manufacturer (Roper) and they told me they don't sell a low-pressure inlet valve.
So I'm wondering if anyone knows how to either:
1. adjust an inlet valve for low pressure water, or
2. create some other solution (other than lifting the rainwater tank higher, which is not an option).
 
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Old 08-01-06, 06:18 PM
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If the solenoid valve opens...it opens. I don't see what pressure has to do with the operation of the fill valve. Hmmm.

I wonder if your real problem lies in the fact that your only approx. 2-3 psi of head pressure from your rainwater tank above can't force enough water fast enough through the fill valve's screen inside the end of each fill valve's water intake port. You could make an experient by putting a rubber/screen hose washer (You can buy these) at the end of the hose (not using the fill valve), and see how much water comes running out the hose. And see if that is indeed what is holding iup the water flow.
 
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Old 08-01-06, 07:20 PM
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Thanks for the idea.
I just checked it out, and a fine mesh filter on the end of the hose did in fact lower the hose's gravity-fed pressure significantly, but not nearly to the trickle that I experience through the washing machine.
The following quote about inlet valves that I encountered online might shed some light:

"Even though these so-called "electric valves" appear to be powered by electricity, they actually use water pressure as their major power source. The electric solenoid on the valve operates a tiny "pilot valve". The water flow from this tiny valve is then used to open and close the bigger valve using hydraulic pressure."

I guess what that means is that the standard inlet valves are built to operate on typical-strength water pressure. Question is how to change that or otherwise compensate for that.

Someone suggested to me to attach a small inline pump, but that would make the system more complex both mechanically and electrically (not to mention just the complexity of installation: I'm not sure if it's even possible to add another electrical part to the same solenoid circuit). It'd be much more "elegant" if I could simply lower the pressure needs of the valve itself. Any ideas on how I can find someone who knows "all there is to know about inlet valves"? Or other creative solutions?
 
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Old 08-02-06, 04:41 PM
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To be honest...I'm like the Wizard of Oz who wasn't sure how to work his hot air balloon. I don't know exactly how they work...the principle of their workings. We do know though that they would have to be designed to open and close, to allow water in, and to keep water out, whether the pressure be 105, or just 20 psi (20 psi is the minimum allowed by law as anything lower can allow infiltration of bacteria in potable systems). I was under the assumption that their was some springlike device that holds it closed up to a relatively high incoming psi force. And that when you want water in, the solenoid would pull back on the tension and let it in, no matter what the psi.

How do you KNOW that the machine is filling slowly? Have you tried to let it fill for a long time, before giving up? Don't forget that it takes quite a while for the *outer* tub to fill water up to the bottom of the inner basket, before you even see any water in the bottom. Even machines hooked up to city water with excellent pressure, this can take a while. THEN once the water reaches the bottom of the inner basket with the holes in it..THEN the filling takes place seemingly faster.

Last night, I too, like other suggestion(s) thought your only other hope is to hook up a real small booster pump to it (that does not require a lot of electrical draw). You would have to tap into the solenoids wire to allow electrical current to split...where current could go to the solenoid and to the booster pump at the same time...and shut off at the same time.
 
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Old 08-02-06, 07:15 PM
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Thanks much for suggestions and reply. It does help me think this problem through.

Yes, it did fill when I hooked the tank hose directly to back of the washer, but took about an hour just to fill for a medium-size wash cycle. Just not practical, and likely overheats the solenoid, which was constantly open the whole time (not to mention the extra electricity that might use). It was just a trickle of water. In contrast, if I just simply hold the hose into the open washer door, it just takes a few minutes.

The booster pump idea is a fairly straightforward one, and it seems like the electrical connection might be fairly straightforward, though I'm a bit worried about mucking it up--not sure for example if best to hook up pump in series or parallel to the inlet solenoid.

I also have seen some internet references to a spring being inside the inlet valves.
Because the valves are not super-expensive, I'm thinking I might buy one and try opening it up to see how I might be able to alter it (such as by putting a weaker spring in it, possibly.

You brought up the bacteria question. I'm not worried about it for the washer because it would not mix with any potable water. Actually, a nearby city's website actually suggests using such rainwater tanks to fill up kiddie pools in summer, so I'm guessing the bacteria risk is not great anyway.
 
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Old 08-03-06, 03:39 PM
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You would tap into the solenoid circuit's hot line anywhere before the solenoid, but after the timer/switch. Wire nutting the wire to continue to the solenoid and to the booster pump together...meaning you will have 3 wire ends in the wire nut. Then for the neutral wire of the booster pump, this could tie into the neutral return line of the solenoid.

But before doing this you will have to see what the gauge wire is to the solenoid and see what kind of amps the booster pump draws to see if the gauge wire to the solenoid can handle the additional juice.

In theory...suppose the wire size was really puny, just suppose. Then the only way I can think of off hand to still tie into the same circuit so both come on and shut off at the same time, would be via contactor type solenoid that would use low voltage to creat the contacts between this circuit and a larger power source. But I think some small booster pump will cause you no real problem.

But keep us updated. This is an interesting project.
 
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Old 08-03-06, 10:56 PM
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Very helpful info, DaVeBoy. I know a little about electrics (which of course is dangerous!) and what you say makes a lot of sense.

It may take me a few weeks to get to the point of actually testing either a modified washer inlet valve or a pump-valve combo. (I'm doing the same rainwater tank source for the toilet and am in middle of working on the inlet valve for that first, which is a bit easier to tackle.)

I also today ordered online a solenoid inlet valve the same type as my washer, to see if I can tinker with it--I should get it in the mail in a few days.
I'll let you know what happens.
 
 

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