Solenoid control valve? (from washing machine)

Discussion in 'The Projects Forum' started by sendthis, Jul 10, 2011.

  1. sendthis

    Thread Starter New Member

    Jul 10, 2011
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    I have a 120VAC solenoid control valve typically used for washing machines.

    Goal: I want to open/close valve with a flip of a toggle switch.
    Question: What (if any) support parts do I need to control this?
    Concerns: I've never worked with solenoid valves so I'm not sure if it needs any supporting hardware.

    Background: This is to control water changing system on an aquarium. Basically, I've split the water source (to the washing machine) with a "Y" adapter and I want to run the supply into a storage barrel. For now, I want to manually control it (so turn it off when barrel is full... automation will come later). Just need a temporary working solution.

    For now, all I want is to have a properly rated toggle switch controlling the solenoid valve. Are there any problems with toggling a solenoid as if it were a light?

    Additional concern/question: I plan to put this in a project box, drill some holes for the inlet/outlet/wires and then seal it tight with silicone. Just in case though, do you think it'll be necessary for me to add an internal fuse to it? I'll probably have it connected to a GFCI anyway.

    Thanks,
    Eric
     
  2. justmark50

    New Member

    Aug 14, 2010
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    You have to use some sort of supressor to dissipate the EMF of the collapsing field in the solenoid coil. If you don't, then the switch will turn it on and when you turn the switch off, the solenoid will take a while to release/disengage.
     
  3. sendthis

    Thread Starter New Member

    Jul 10, 2011
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    So use a Panasonic ZNR -or- a flyback diode in parallel or is this a different issue?
     
  4. praondevou

    AAC Fanatic!

    Jul 9, 2011
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    Do you have any ratings of the solenoid you are using?

    (current / inductance)

    If it was me I probably wouldn't waste much time with this, I'd just use a light switch and see what happens. I certainly would not use these small toggle switches you put on a PCB.
    I had once a broken solenoid in my washing machine, it blew up a triac too... I can't remember having seen a big snubber or something, so I wouldn't be too concerned about the collapsing magnetic field, although this effet exists, of course.

    cheers
     
  5. sendthis

    Thread Starter New Member

    Jul 10, 2011
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    No, I can't find the datasheet on the solenoid. It's for a washer/dryer. Looks pretty standard, fits the GE models (which works out b/c I have a GE washer if I ever need a replacement part fast).

    I originally thought a light switch, but decided against it, but I'm open to using it. The main reason for using anything else is to reduce the footprint and ease of mounting for the box (drill a small hole).

    I don't have a problem putting some simple passive devices in parallel though if it increases the lifetime of the device (and especially if it increases safety).

    I might throw this whole idea out altogether though and buy pre-manufactured systems. I don't have a problem working with electricity but throw in water and I get a little uncomfortable. I'm not at ease with just working with plumbing b/c I always worry how something leaking is going to cause thousands in damages. I suppose there are always the electrical fire concerns for the other side of it.

    Other than simple basic house wiring I usually stick with digital electronics :/
     
  6. praondevou

    AAC Fanatic!

    Jul 9, 2011
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    Do you have the solenoid control circuit? I assume you took the solenoid from an old washing machine? If so the easiest would be to use part of the "old" control circuitry, then you don't even have to worry about working with higher voltages...
     
  7. ifixit

    Distinguished Member

    Nov 20, 2008
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    Hi sendthis,

    I have used these control valves before for lawn watering projects. They use 5 to 10 Watts of power, very little. Any switch approved for 120VAC at 1A, or more, will be over-rated and fine for your purpose.

    The washing machine application only required these valves to be on for short periods while the tub fills. Therefore, they may overheat if left on for extended periods of time (hours). When you test your application, pay attention to the activated valve to see if self-heating is a problem, if not you're good to go.

    If you activate with a triac, use a snubber circuit across the triac to protect it from the fast edges of the inductive back EMF. A typical snubber is 100Ω in series with 0.1uF 250V, or buy a snubber with these components built in and approved for the purpose.

    Regards,
    Ifixit
     
  8. CDRIVE

    Senior Member

    Jul 1, 2008
    2,223
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    Washing machines with included solenoid valves have been around for a very long time. Fact is they were being used long before solid state even existed, so there were no transorbs or other solid state spike devices used with them. In those days they were activated by a motorized timer that simply closed switch contacts. Since you won't be protecting sensitive solid state controlling devices I don't think you need anything more than a 120VAC rated switch.

    Since this is an electronics forum we sometimes tend to over complicate things. ;)
     
  9. praondevou

    AAC Fanatic!

    Jul 9, 2011
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    Good point! :D
     
  10. sendthis

    Thread Starter New Member

    Jul 10, 2011
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    That's reassuring to hear all of the above (no snubber circuit). I didn't pull it out of an old washer, I just bought it on eBay ($11). I figured it's probably pretty reliable because no manufacturer is going to stand behind a washer that leaks all the time. It also worked out because it had two valves in one and I need the hot and cold source.

    I don't plan to have it on too long. It's going to be used to fill a 55G barrel, maybe two, but it won't be for continuous use.

    I do eventually want to control it with electronics, but that's for another day. I'm going to work in stages. Get it working 'manually' first and then add additional equipment. I figured if I planned too big I would never get the project off the ground.

    Thanks again for the help... I might do some more research on the snubber circuits and add it in anyway, just because I might eventually need it.

    Regards,
    Eric
     
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