6 ms·

Running the hot water tap beforehand assumes that the dishwasher is hooked up to the hot water in the first place, which isn’t common everywhere. Where I live

by bakje 11mo ago

Running the hot water tap beforehand assumes that the dishwasher is hooked up to the hot water in the first place, which isn’t common everywhere. Where I live this feature is called hot fill, I believe, and a lot of dishwashers don’t even support it. For those that do support its still generally not recommended to use it since the dishwasher now can’t do any rinsing with cold water, which is not only wasteful but I’ve heard the hot water can damage the water softener in your dishwasher. But if you do hook it up to hot water (which is a lot more common in the US, I think) this makes a lot of sense.

mitthrowaway2 11mo ago
And lo, there is verily even more information presented in the video than this thread has yet revealed. For what Alec says in the video is that this purge-the-cold-water advice is specific to North America, and he even explains the reasons why!
- bakje 11mo ago
  Haha I have to admit I didn’t watch the whole video. In which case my comment still stands for those who also haven’t watched the whole video, which is probably a fair amount of people
- krige 11mo ago
  He does mention it has to do with voltage and heating systems. I think it's something he covered on his kettle vid.
  - inferiorhuman 11mo ago
    He mentioned that it's not due to voltage but rather low current circuits. A 15 amp circuit translates to around 1,800 watts in the US and if you derate it to 80% of that like the NEC requires a continuous load you'd have around 1,440 watts available. His argument is that appliance manufacturers are trying to simplify their lineup by making models that would work in homes without a dedicated circuit (15 or 20 amp). Although I can't think of a better argument that still doesn't quite sound right to me. The NEC has required dedicated circuits for dishwashers for quite a while now and IIRC that requirement has been for a 20 amp circuit for a few decades. Even though you typically only see 15 amp receptacles, kitchens have required 20 amp circuits for somewhere north of forty years. I think a lot of his video is simply based on testing with crappy Whirlpool and AEG dishwashers. There's a reason why Bosch (and these days LG) dishwashers are pretty much universally recommended.
    - Turskarama 11mo ago
      It's the same issue, if you have a higher voltage then you can get more power without increasing current. For example in Australia a standard house circuit is 10 Amps, but because it's at 240V we can get 2400 Watts (realistically more like 2300) out of a _standard_ wall outlet that is in every room of your house.
      - inferiorhuman 11mo ago
        It's not the same issue. The vast majority of kitchens in the US have 20 amp circuits (so 2,400 watts peak, 1,920 watts continuous) exclusively. It's a bog standard receptacle (NEMA 5-20R instead of 5-15R) that's backwards compatible with 15 amp plugs. In fact these days most 5-15R receptacles have identical guts to their 20 amp counterparts save for the additional provision for a horizontal blade. The electrical code (NEC) has started moving towards requiring 20 amp circuits in other rooms and more 20 amp circuits in kitchens.
        deleted 11mo ago
        [deleted]
        Dylan16807 10mo ago
        But they're staying shy of the amp limit on purpose. So designing for 20 amps would be somewhat of a boost but not enough. While doubling voltage would actually fix the problem.
        inferiorhuman 10mo ago
        You're going to stay below the circuit breaker rating no matter the voltage. Nobody's going to put a 2,400 watt heater in a dishwasher designed to be used on a circuit that tops out at 2,400 watts because: a.) I'm going to go out on a limb and suggest that most countries will place limits similar to the NEC's 80% rule. b.) There are other high current draw devices in a dishwasher that will have to run concurrently like the water pumps. Same with things like electric kettles. You're not going to find 1,800 watt kettles in the US even though they're designed for circuits rated at that. A quick peek at the kettles available in Australia show that most top out at 2,200 watts for the same reasons. In the context of a dishwasher 240V would only get you more powerful heaters than you could run in the US if the circuits were rated at more than 10 amps. Voltage isn't the issue.
inferiorhuman 11mo ago
the hot water can damage the water softener in your dishwasher Most dishwashers in the US don't come with water softeners. AFAIK European made American market Bosch 500/700 series ones do, but the American made ones do not. Both would be designed for connection to a hot water supply. As heated air drying (in the US) has fallen out of favor, hot rinse water will help things dry faster. To that end my Bosch dishwasher has an option to increase the temperature of the rinse water.

by bakje 11mo ago

mitthrowaway2 11mo ago

And lo, there is verily even more information presented in the video than this thread has yet revealed. For what Alec says in the video is that this purge-the-cold-water advice is specific to North America, and he even explains the reasons why!

bakje 11mo ago
Haha I have to admit I didn’t watch the whole video. In which case my comment still stands for those who also haven’t watched the whole video, which is probably a fair amount of people
krige 11mo ago
He does mention it has to do with voltage and heating systems. I think it's something he covered on his kettle vid.
- inferiorhuman 11mo ago
  He mentioned that it's not due to voltage but rather low current circuits. A 15 amp circuit translates to around 1,800 watts in the US and if you derate it to 80% of that like the NEC requires a continuous load you'd have around 1,440 watts available. His argument is that appliance manufacturers are trying to simplify their lineup by making models that would work in homes without a dedicated circuit (15 or 20 amp). Although I can't think of a better argument that still doesn't quite sound right to me. The NEC has required dedicated circuits for dishwashers for quite a while now and IIRC that requirement has been for a 20 amp circuit for a few decades. Even though you typically only see 15 amp receptacles, kitchens have required 20 amp circuits for somewhere north of forty years. I think a lot of his video is simply based on testing with crappy Whirlpool and AEG dishwashers. There's a reason why Bosch (and these days LG) dishwashers are pretty much universally recommended.
  - Turskarama 11mo ago
    It's the same issue, if you have a higher voltage then you can get more power without increasing current. For example in Australia a standard house circuit is 10 Amps, but because it's at 240V we can get 2400 Watts (realistically more like 2300) out of a _standard_ wall outlet that is in every room of your house.
    - inferiorhuman 11mo ago
      It's not the same issue. The vast majority of kitchens in the US have 20 amp circuits (so 2,400 watts peak, 1,920 watts continuous) exclusively. It's a bog standard receptacle (NEMA 5-20R instead of 5-15R) that's backwards compatible with 15 amp plugs. In fact these days most 5-15R receptacles have identical guts to their 20 amp counterparts save for the additional provision for a horizontal blade. The electrical code (NEC) has started moving towards requiring 20 amp circuits in other rooms and more 20 amp circuits in kitchens.
      - deleted 11mo ago
        [deleted]
      - Dylan16807 10mo ago
        But they're staying shy of the amp limit on purpose. So designing for 20 amps would be somewhat of a boost but not enough. While doubling voltage would actually fix the problem.
        inferiorhuman 10mo ago
        You're going to stay below the circuit breaker rating no matter the voltage. Nobody's going to put a 2,400 watt heater in a dishwasher designed to be used on a circuit that tops out at 2,400 watts because: a.) I'm going to go out on a limb and suggest that most countries will place limits similar to the NEC's 80% rule. b.) There are other high current draw devices in a dishwasher that will have to run concurrently like the water pumps. Same with things like electric kettles. You're not going to find 1,800 watt kettles in the US even though they're designed for circuits rated at that. A quick peek at the kettles available in Australia show that most top out at 2,200 watts for the same reasons. In the context of a dishwasher 240V would only get you more powerful heaters than you could run in the US if the circuits were rated at more than 10 amps. Voltage isn't the issue.

inferiorhuman 11mo ago

the hot water can damage the water softener in your dishwasher Most dishwashers in the US don't come with water softeners. AFAIK European made American market Bosch 500/700 series ones do, but the American made ones do not. Both would be designed for connection to a hot water supply. As heated air drying (in the US) has fallen out of favor, hot rinse water will help things dry faster. To that end my Bosch dishwasher has an option to increase the temperature of the rinse water.