Come to think of it, I did replace the motor a couple months ago. Didn’t think of connecting the two. Cost me $80 to fix (I fixed it myself.) This particular model did have issues with the motor blowing out early, according to the literature I’ve seen online, but now I wonder if the two are connected. The only thing I see on Kitchen Aid’s website is that if the water coming in isn’t hot enough (because the hot water line is located far from the heater), that the loads may not wash well, but nothing about it being dangerous for the equipment.
I was just suggesting that a bad motor would likely cause you to buy a new dishwasher before the element gave out. I’d be very, very surprised if they’re related in any way*. Even then, I was only saying it because when my motor was getting louder and louder I checked online and the cost for a new one (motor, part only, I can fix it) was about $250-$300. Hardly worth it on such an old dishwasher, especially when I can get a brand new ‘good’ one for $400-$500.
*I suppose cold water could cause a seal somewhere to shrink and let water drip down in to the motor, but that’s a long shot.
:smack: Gotcha. That makes a lot more sense. Yeah, I got a little lucky with this part. I found the motor assembly for $120 at most places, but managed to get it new for $75 (plus tax) from Sears.
All the dishwashers I’ve had have been connected to the cold water supply. The current one (a Bosch) mentions an option to connect to the hot if you change a setting, but why would I when it has a built in heater? My hot water gets to maximum of 50 degrees Celsius anyway and the normal wash in the dishwasher is something like 60 or up to 75 degrees.
As for the OP’s issue, I had much the same when the heater stopped working in my previous dishwasher. In my case, it was the circuit board of the controller, which had an under engineered track for the water heater. After a time it just burnt out because it couldn’t carry the current needed.
Also, I’ve always been told that water heaters should store at a temperature of at least 60 degrees to prevent bacteria growth. That’s 140 Fahrenheit. Do you have tempering valves to keep the temperature at the tap below 50 (120 Fahrenheit)? I have a tankless heater, so there is no storage.
This Old House, who certainly know more about house stuff than I do, say that it is more efficient to let the dishwasher heat the water than to use water from the hot water heater. Is that true? Particularly with a gas storage hot water heater compared to the electrical resistance heater in the dishwasher, I’d think the hot water heater is much more efficient at heating than the dishwasher.
I drain the cold water from the hot water pipes before starting the dishwasher, but I’m using that water to run the garbage disposal anyway, so it’s not completely wasted.
I do find it odd that dishwashers and washing machines will say that the incoming hot water should be at 120F or higher, but child safety advocates will say to set it below 120F.
It’s probably worth mentioning that even if the dishwasher can heat the cold water with no problem and even if it costs the same to have either one heat the water, the dishwasher manufacturer is still going to prefer hot water to come in since that puts less stress on the heating element, speeds up the cycle time by reducing how long it has to wait for water to come up to temp* and, not running the element as much means it uses less electricity. Even though you’ll still pay for that energy at the water heater, the actual dishwasher will use less and the big yellow sticker on the box showing energy usage will look better.
*I don’t actually know if the machine waits for the water to heat up. It probably varies from machine to machine, but it can’t take more than a few minutes so the cycle might just start anyway and the heater/t-stat do their thing.
We’ve got some pretty damned cold groundwater here, especially in the winter. I have never seen a dishwasher here connected to a cold water line. Hell, I’ve installed a couple myself and didn’t even know it was an option. In fact, it probably isn’t.
I have a countertop dishwasher, that hooks up to the spit, set for Hot.
This seems pretty questionable to me.
It’s at the very least going to vary locally. The dishwasher is likely heating the water electrically, while my water heater is gas. It is definitely not going to save me money to heat up water with electricity compared to gas.
In general a resistive heating element surrounded by water is going to be as efficient as any other resistant heating element surrounded by water. Pretty close to 100% of the energy is going to go into heating the water. I guess you have lower transmission losses if you’re heating the water at the dishwasher and not warming up the pipes, but again, that will only be relevant if your water heater is electric. Many are not.
Thanks for everyone’s thoughts. Now, let’s try a slightly different angle of attack: What is the ballpark price for a new heating element? Is it worth replacing the element or simply replace the dishwasher? (FYI: I can share our water softening system recently got a “tune-up”. It was my misunderstanding thinking that the whole system can regenerate itself. This is only half-true. So, a new dishwasher will reap the benefit of the recharged softening system. I will share that, in general, I do not see scaling building up elsewhere inside the dishwasher.) Meanwhile, I will take a close look at the heating element for scaling and will verify my water supply IS from the cold water supply. …Maybe the heating element simply burnt out.
For the dishwasher I have, the heating element is about $70, plus shipping, online from www.appliancepartspros.com (just the first site I found). The dishwasher is about $800-$1200, plus installation.
Now, unless you repair it yourself, it will probably be $250 in labor for the repairs, or more. If the heating element is what is bad, it is still obviously cheaper to repair, but if it’s something with the electronics that turns on the heating element, it could easily make more sense to replace it than repair it.
BTW, I don’t think hard water will harm the heating element in a dishwasher, at least the ones I am familiar with. Hard water kills the heating elements in water heaters because the scale precipitates and falls to the bottom of the tank, settling on the element. When the element gets covered with scale, it can overheat as well as suffer corrosion issues. With the dishwasher, the scale isn’t going to build-up, so it sholdn’t affect it. The soft water will reduce spots on the glassware, though.
For me, it’s crazy because the hot water is already hot thanks to our gas water heater, and paying for the electricity to have the heating element heat it is much more expensive.
Either way, if you’re using X gallons of water heated to 60C, you have to pay to have X gallons heated up, whether it’s in the washer itself, or in the hot water heater.
Diving a little more deeply…and these apply to Australia.
From here.
From the installation manual for my dishwasher:
From the paper in front of me.
Now, that’s a pretty narrow window - much easier to heat the water that the dishwasher needs in the dishwasher, I’d say. I’m not a plumber, true, but I can’t imagine going to the extra trouble to attach a temperature tempering valve, to hook a dishwasher to hot water, when there’s no good reason to do so.
Bear in mind that not everyone around the world has unlimited hot water. For me, how much hot water I have depends on how much sun I had today, as well as whether I remembered to turn on the boiler’s electrical heating. In any event, I wouldn’t waste hot water on a machine that can heat water itself.
My dishwasher is under the counter in kitchen next to the sink. It is connected to the sink’s hot water line only. We usually run the hot water tap in the sink until hot water comes out before starting the dishwasher.
The heating element as far as I know, only comes on at the end of the wash cycle to dry the dishes.
I installed it per the directions a couple of years ago.
Right, but for many people the water heater is a lower cost heater than resistive electrical heat. Not everybody, but quite a lot. Because burning something locally to make heat is a lot more efficient than burning it to heat water to spin turbines to oscillate electrons to heat up a resistor a long way away.
I don’t think five degrees C is that narrow a window. Water heaters have a thermostat in them, so you can just set it to something between 60 and 65. Not sure that “easier” matters much. Like, both heaters are present, so you should use the lower cost one.
If all your heating is electric, then it doesn’t matter. If you have some combustable source of heat, then that’s almost certainly a cheaper way to heat things.
Diving off tangent for a second - I’d literally never heard of the recommendation to keep your water above 60 degrees - in fact, the last thing I’d heard on the subject was a recommendation to go as low as was practical, to save money and keep your kids from scalding themselves. So thanks for your cite - that’s interesting and thought-provoking.
Back on topic, it just shows that dishwasher manufacturers can’t reliably assume anything about the temperature of the water going into a machine. Who knows, in another 10 years someone may come up with a reliable method to eradicate all legionella from the environment, and then we’ll be back to keeping our tanks at 45 again.
I didn’t read every post - has anyone suggested cleaning the filter? Some DW have self cleaning and others don’t. Mine does not and needs cleaning about once a month.
Not a plumber, but a master carpenter and project manager. Western Canada. I have dishwashers reconnected nearly every week for at work. Always, always to the hot water line.
My Miele at home and the many I have had hooked up, all to the hot water line. I have been told by service guys its a good idea to run the hot water tap before the dishwasher to make sure the machine is getting nice hot water. Most machines have no system to heat the water, and a lot of newer machines that rely on drip drying have no heating system at all.
When I got my current dishwasher, I had to check every model I looked at to make sure they had the ability to do heated dry. While I’m sure leaving that option off saves money for them, it also makes the unit look more energy efficient since it uses less power than a similar unit that runs the element at the end. I’m glad I caught that. I would have been disappointed if it didn’t have that. I know some of the newer units right now will pop the door open a bit to help them dry at the end (without heated dry), I don’t know if other ones run a fan or do anything at all to help them dry.