Hot/Cold water crossover with single faucet?

[Sensible]

This could be a plumbing question, but it stems directly from hooking a portable appliance up to your sink:

If you don't have the option of hooking up to the hot and cold water sources separately, the alternative is to hook up to the sink's one spout. Works fine, till the appliance stops taking on water. Then, with the spout effectively capped, what's to prevent the hot running into the cold water supply, or vice versa, depending on which happens to have more pressure?

Assuming this is the case, I've always opened only the hot faucet or only the cold. Am I being overly cautious?

[HayZee518]

for a portable appliance - dishwasher, why would you open both hot and cold supplies? same goes for a portable washer unless you want luke warm water

[Sensible]

Yes, the point would be to wash in warm water, not hot. Without having to wait till the tub is half full, then switch over, and hope you're there for the rinse.

But without a backflow-preventer in the supply, I'd think this inconsiderate to the building's next water user down the line, who may also receive lukewarm water from their hot or cold faucet. Not to mention inefficient if you're paying to heat the water.

[HayZee518]

that would be something to take up with your landlord. they tend to put in the cheapest appliance they can just to make a buck, even though the utility bill comes in your name.

[mrcaptainbob]

Water supply....

I was under the impression that only hot water was to be run to a dish washer. Even a built in has only one supply line. And that's directly to the hot water line.

[Sensible]

Ooops. I meant Washing Machine


Sorry, it's finally sunk in that I should have written "washing machine" instead of just "appliance." Yes, I, too, prefer that my dishes be washed in the hottest possible water.