Washing machines use floats....right?

I recently had an epihany that I could save a few cents by dumping the dehumidifier water into my washing machine (okay, it was laziness, it’s a few inches closer then the sink). I just wanted to make sure that the water is shut off becuase of sensors or floats being tripped right? I guess there’s a small chance it could be based on time, but that wouldn’t work very well becuae even though the water is supposed to come into the house at 60psi, I’m sure that’s not always the case. So am I right in assuming that no matter how much water I introduce into the machine, there’s no chance of it overflowing.

The washers used to be strictly controled by timers. They may have gone to sensors now, but I can’t verify it. I had access to Whirlpool engineers at my old job, but that’s over.

I would woory more about the clothes coming out smelling moldy, because of water setting in the tub for long periods. The dehumidifier might not add nutrients to the water, but the washer tub has enough nutrients to grow bacteria and molds.

I think that Harmonious Discord is only partly right about the timer control – there was more to it than that.

I know, for example, that back in the 70s when I had reason to tinker with my parents’ discarded old washing machine, the fill valve was triggered by a weight-sensitive switch which sat beneath a rubber diaphram at the bottom of the basin (not by a float switch). Only when the basin was filled with a predetermined amount of water, would the switch would turn the fill valve off. So presumably, you could keep adding water from an outside source and the basin would continue to fill.

My guess is they either have a float, or as stuyguy mentioned, some sort of pressure sensor. Whatever it is, it has to be easily adjustable, since your washing machine has a fill adjustment, right? In any case, I have done what you suggest many times. Aafter a detergent bottle empties, I fill it with water an pour it in the washer to get every last bit of detergent. I’m not just being cheap, it’s easier on the environment and the bottle is more easily recycled.

I’m also guessing that as a safety feature if the float fails, the washer has some sort of timer that turns off the water if it remains on for too long a period of time. This would prevent the washer from overflowing. Dryers have similar mechanisms for shutting off if the moisture sensor fails and the dryer thinks the laundy is wet when it isn’t (overdrying too long might cause a fire).

BTW, I’ve noticed that even after the washer fills, if you turn the fill adjustment to the “reset” position while it’s running, the agitator stops and the water starts flowing again. Let it go and the water stops flowing and the agitator starts up again. WTF?

We do wash at most 4 or 5 times per day and at the least every other day. So it’s not that the water is going to be sitting in the basin for weeks or months. Besides, I beleive there’s always some water down there anyway (I could be wrong, I just remember reading that people that keep their washing machines outdoors need to put some antifreeze in it to keep any residual water from freezing and bursting a line.

I still have a hard time thinking it’s on any kind of a timer. If someone is taking a shower, and the dishwasher is filling and I’m watering the lawn it seems like it might not get filled all the way.

As for a weight type sensor, wouldn’t the water not get filled properly if there was a heavy load in the tub (say a tub full of jeans or damp towels). It just seems like the most logical way to do it would be three (one for each fill height) sensors or floats (though floats would bob with the agitation and possibly cause problems.

Oh well. I’m only adding a few gallons, hopefully not enough to cause it to overflow.

All the machines I have had to deal with (UK models) have a pressure sensor that can detect various levels to deal with wash/half load/rinse etc. A float would be cumbersome to say the least.

I used to do appliance repair on the side, and every washing machine I ever looked at used low range pressure switches (calibrated in “inches water column” not too surprisingly) to control the water level. The water level adjustment on the front panel adjusts this up and down across the appropriate range.

So you should be able to manually fill the tub half way, turn on the washer, and the normal fill cycle will top it off correctly.

On the other hand, most (I don’t recall if it was all, but I think it was) dishwashers used a timer on the water inlet valve to control the level. They got away with this for a few reasons: The exact level wasn’t as critical, there isn’t as much water used so a difference of even 20% wouldn’t cause an overflow, and they usually had a crude pressure control on the water inlet. This was usually just a flexible washer that changed the inlet orifice size slightly as the pressure changed. So if the water pressure was above some minimum, and not ridiculously high, you get enough water to work, and not so much as to overflow.

That experience is now 20 years old and things in the new computer models may be different, but I think washers are still going to be using pressure switches or some other actual level sensor.

The timer controls when the water is allowed to flow. There could be a saftey switch to prevent over flow, A float switch would always stop at the same level and not allow for low medium and high levels with the dial. The knobs are all electrical controls, not a mechanicaly adjustable float.

I’ll agree with the pressure valves, but if timer says time to pump out water, the fill won’t happen when the pressure valve wants to. That circuit is dead until the timmer says ok to fill again.

Let me address this quickly.

The pressure sensors are plumbed so that only the weight of the water affects them. The weight of the water is determined only by the height of the water above the switch, not by the amount of water.

So if you put a large load of clothes in the tub, it takes less water to get to the same height, where the pressure switch cuts it off. The weight of the clothes themselves have no effect on the weight of the water pressing down on the switch.

Actually, in the machines I worked on, the most common water level control actually did directly adjust the pressure switch mechanically. This was sometimes by a linkage, but most usually by the switch being in the control panel directly behind the adjustment knob, and the knob just adjusted the pressure on a spring.

In order to correctly sense the weight of the water, a little rubber hose that had air in it went down to below tank level, where it stuck in the side of the plumbing under the tub. The weight of the water pushing into the air tube would compress the air slightly and you get just about exactly the same pressure as you would if the switch diaphragm itself was down at that level. The weight of the air in the tube was small enough in comparison that it had no real effect on the pressure.

Well I filled the tub about halfway with dehumidifier water and then ran a load of clothes without flooding my basement. So even without a solid answer, I know I’m safe to do it.

Ha, I do the same thing. Filling the tub with dehumidifier water that is. Must be a Milwaukee thing. :smiley: Never had any problems, I’m pretty sure the tub always tops off to the same level no matter how much outside water I add.