can you connect dishwasher to hot water supply?

[SparkyTris]

Well, clearly you can: I just have. but is it about to explode?!

An old AEG dishwasher model OKO Favorit 80800 Sensor Logic. Has one water intake. hose on said water intake is grey plastic effort with normal "washing machine" threaded connector. On this connector it says "90 degrees C max".

I have proved that the machine works fine with a cold supply. I guess it has an inbuilt water-heater & thermostatic control to make its own hot water.

what could be wrong with connecting it to the domestic hot water (which comes from a large hot water vessel, nominally running at about 50 C by the feel of it). electrically heated.

the dishwasher appears to have programs that run at lower temperatures (eg a "quick 40", whatever that means).

it seems unlikely that the machine will have a built in water cooler, so should I expect errors if/when it detects overtemperature?

why are all washing machines etc have only a cold feed since about 10 years ago? seems inefiicient in a setting with plenty of hot water sitting in a large bottle, but I am likely missing something.



duplicate removed

 

[Ian H]

I’d guess it heats its own water because they use hot water in short bursts so if it took hot from a Combi Boiler it would never get any.

 

[Tigercubrider]

I must admit that I don't understand why clothes machines don't work off. Hot water if available.

My dishwasher (I believe) heats the water or wash but uses cold todo the rinse before washing? And once clean, afaik the dishwasher runs cold water over the casing to encourage the dishes to dry? Or maybe I am wrong

 

[JohnW2]

I must admit that I don't understand why clothes machines don't work off. Hot water if available.

As has been said/implied. the small volumes of water drawn by modern machines is so small that, unless the hot water source is very close to the machine, it would not usually get much/any hot water even if it were connected to a 'hot water pipe' (all that would be drawn would the fairly cold water from the pipework.

Kind Regards, John

 

[Mottie]

I must admit that I don't understand why clothes machines don't work off. Hot water if available.

From what my wife tells me, most of our washes are at 30° or 40° and with just one water connection, you’ll end up with water going into the machine hotter than that plus you’d have no cool wash options and hot rinses.

 

[JohnD]

for dishwashers, rinsing in hot water would do no harm, and you would shorten the cycle a bit. Our dwr heats for 11 minutes for hot wash, and again for final rinse, at 2kW. As long as the max temp stated by the maker is no lower than your HW temp, I can't see it would do anything but good. Energy from electricity costs around four times as much as energy from gas so it would probably save you money.

Our washing machine has hot and cold fills, but is some distance from the cylinder so we run the adjacent hot tap before starting. it takes in hot water for everything but the cool/delicate cycles. The drum and tub absorb some of the heat so it still runs the heater for most things. Bio powders are better starting cold as the enzymes are inactivated when they get hot.

If you do mostly cool washes the machine is likely to get an accumulation of sludge from soap and fabsoft. A hot hot hot wash of white cotton towels will help dissolve it, as will washing soda. The sludge can smell rotten when bacteria colonise it and live in the tub.

 

[winston1]

Energy from electricity costs around four times as much as energy from gas so it would probably save you money.

But the OP said "domestic hot water (which comes from a large hot water vessel, nominally running at about 50 C by the feel of it). electrically heated."

 

[JohnW2]

But the OP said "domestic hot water (which comes from a large hot water vessel, nominally running at about 50 C by the feel of it). electrically heated."

Indeed - and, as far as I can see, that means that, unless that water is heated by cheap-rate electricity, there is quite probably going to be an increase in energy costs with a hot feed because (a) additional heat loss from pipework and (b) some parts of the cycle (e.g. rinsing) might unnecessarily be using water that had been heated (if it would otherwise use cold, or colder, water for that).

Kind Regards, John

 

[AndyPRK]

I have a very old dishwasher (1980s), which instructions state a hot water supply is preferred.

I recently connected to the hot water supply and now the cable no longer goes more flexible when used (as the heating element isn't being used) so should save some electric on the bill.

I also have a modern DW, which again requests HW and it is what I use. No issues

 

[JohnW2]

I recently connected to the hot water supply and now the cable no longer goes more flexible when used (as the heating element isn't being used) so should save some electric on the bill.

Do I take it that your hot water is gas-heated?

Kind Regards, John

 

[AndyPRK]

yes,

 

[JohnD]

good

 

[SparkyTris]

yes our water is some variant of economy seven, so the water is heated by the least expensive means in the local area (ther is no mains gas here)

 

[AndyPRK]

So at long as you set the DW off at night, when there is plentiful HW then that is fine. (you don't want it using HW you could use for other things).

But of course you could just set the DW off at night (connected to the cold supply) and that may even be slightly more efficient! But you would need timer you trusted to cope with the 13A load

 

[JohnW2]

yes our water is some variant of economy seven, so the water is heated by the least expensive means in the local area (ther is no mains gas here)

No mains gas here, either, which is why my hot water is also E7-heated.

In that case, there would probably be some cost saving to be had by using a hot water feed to the machine. Of course, if (like me) you were semi-nocturnal, you could just run the machine during the off-peak hours - in which case not only the water heating but also the motor etc. would be enjoying 'cheap electricity'.

Kind Regards, John
Edit - ah, a bit too slow with those last comments!