Water Inlet Valve - Ice Maker

[TymerTopCat]

Problem: I have a Whirlpool ice maker that works, but only produces half of the ice during an ice cycle. This problem is because the ice maker is connected to a Rerverse Osmosis (RO System) it has low water pressure. The ice maker does have a water level adjustment, however the adjustment is not enough to fill the ice tray.

Problem: Ice maker turns on the water inlet valve for 7 seconds, I need the water inlet valve to produce water for about 12 seconds instead of 7.

Possible Solution?
Build an analog circuit that uses the 7 seconds of 110 volt output from the ice maker, and creates a (delay off) timer of 12 seconds.

Would this be possible?

Said in other words, the ice maker energizes the water inlet valve (110 volts) for 7 seconds, I need to keep the Water inlet valve open (energized) for 12-15 seconds. Could we use the seven seconds of (110 volts) to charge a capacitor, and then use the capacitor to energize the water inlet valve for 12-15 seconds? The timing of the circuit does not matter as the ice tray fill is the last step in the ice making cycle.

 

[d123]

Hi,

Doubt it. A capacitor charges up to ~63% in one time constant but discharges down to ~37% in one time constant...

Why not look into 'off-delay' relays or modules instead?

 

[TymerTopCat]

Thanks for your reply. I am a software engineer, but not a Electrical engineer. And so I was ignorant of "Off-delay" relays.
I am currently looking into the relays.

I was just looking to solve a simple problem with the simplest solution.
The Off delay relay looks to be one way to solve my problem.
If I am thinking correctly the Off Delay relay can be set to delay off in any number of seconds:

Not sure how to wire this Off Delay relay into the system. Because I don't know (yet), the behavior of the Off Delay Relay.
If I wire the Off Delay relay to the ice makers 110/120 volt output in front of the Water Inlet valve, When the Ice Maker energizes the Off Delay relay for 7 seconds and then turns off. Will the Off Delay relay continue to energize the Water inlet valve for 5 more seconds, after the the power is cut?

I may have to have an additional power wire to power the Off Delay relay?

 

[d123]

Hi,

...and I don't know anything about the innards of icemakers, unfortunately.

Pictures of wiring and documents or links to device specifications are a more accurate way of people offering informed suggestions.

You can get on or off delay switches that turn on or off at the start or end of a signal, all flavours for all needs, and additional power path would be needed for one.

If you can put together a picture of the icemaker wiring, a smarter person than myself will be able to suggest what goes where, hopefully.

 

[BradtheRad]

Here's a method to extend a DC pulse (although it's not clear if the initial signal is AC or DC):

To obtain longer discharge time from the capacitor, we can make the transistors a Darlington pair, which draws very little bias current from the capacitor. Thus its value can be small and less expensive. With a little effort you can change it to an NPN-PNP pair, relay, scr, etc.

This is theoretical of course. The above is similar to a sample-n-hold circuit. It's not likely you can simply drop it into your ice maker. You need to find out whether its voltage is AC or DC, and how the 7 seconds of On-time is obtained.

And your whole job is easier if you can find a built-in adjustment for On-time in the ice maker.

 

[KlausST]

Hi,

First please download an OFF_delay_relay datasheet. There should be wiring examples (if not choose another datasheet).
Read to them.

If then still something is unclear, then please post a (hand drawn) sketch of the current wiring.

Klaus