something different- washing machines. - concrete

I am sure that amongst this happy throng of posters and threaders there will be a trained technician with the answer to my question. I intend to re-arrange our utility room. I need to move our washing machine to another location. The washing machine has only a cold fill connection. The new location has both hot and cold connections. I am thinking it would be more efficient to fill the washer with hot water we already have on storage, rather than cold and have the washer heat it up with an electric element. Would it affect the washing machine to do this? Our dishwasher is a hot fill device and has worked for over 20 years without a problem. Advice please. Concrete

something different- washing machines. - Bobbin Threadbare

In general, this will be more efficient - it's basically what the 'eco' mode on newer washing machines does. Saves using the eleccy as you're not working the element of the washer.

I can't say I have any idea whether this will damage the machine, but if it were my washer, I'd be looking at how tough the inlet pipes are and whether they could withstand hot water streaming in instead of cold. They look to be the same kind of pipe on my machine.

20 years is good going!

something different- washing machines. - bathtub tom

The hot water pipe will be full of cold water, that will feed the machine first before any hot reaches it. When the machine stops the hot water supply the hot water pipe will be full of hot water which will then slowly cool, wasting the energy spent in heating it.

I think you'll find most modern machines are cold-fill only because they use less water than older machines and due to the length of supply pipes it's just not any efficiency saving to have a hot fill.

In my experience, machines that have a hot fill don't have any variable control, so when hot water's called for, a mix of hot and cold is supplied because the hot may be at a higher temperature than the wash temperature selected.

I've never come across a hot fill dishwasher (but none of mine have lasted twenty years).

My recently purchased dishwasher claims to be efficient on water usage (I don't have the figures to hand) and the instructions advise: "not to connect to hot water if the water is supplied from an electric boiler".

something different- washing machines. - concrete

Thanks Bobin and Bathtub. I appreciate the point about drawing hot water through the supply pipe. The washer will be next to a sink which is in use and mostly hot water will have been drawn through to this point anyway. The pipe to the washer seems to be of equal quality and strength to hot and cold on other machines. The original Neff dishwasher offered either hot or cold fill, so hot was chosen at that time, still going strong. The washer in question is a high efficiency model with some very quick programmes and low water content. I will have to ponder on the efficiency question. To heat by electric element or draw pre-heated water? A tricky one. I don't now think the machine will be affected as long as it has an adequate water supply. Thanks again. Concrete.

something different- washing machines. - daveyjp
On a 30 degree wash cold water doesn't need heating much, especially when required in small quantities.
something different- washing machines. - Chris M

You may or may not save leccy by supplying pre heated water for the wash cycle, but what efficiency gains do you expect by rinsing three or four times in water at 50 - 60 degrees C against the perfectly adequate cold supply? I'll also hazard a guess that the clothes would come out more creased from a hot rinse (tumble driers have the cool down cycle to minimise this). This won't be an issue if it's your other half that does the ironing ;-)

Edited by Chris M on 15/02/2012 at 13:25

something different- washing machines. - Bromptonaut

Dish washers wash dishes and even on an eco programme have a hot rinse so that warmed crocks dry by evaporation.

A washing machine washes once in water at temperature chosen for fabric and/or detergent efficiency then rinses cold. Filling a machine designed for cold supply from hot will defeat the temp control and potentially shrink your delicates. Washing over 40 degrees will also remove any benefit from bio detergent.

If the hot wash doesn't spoil your clothes the hot rinse will.

And hot rinses will kill any marginal saving from using water from the boiler in the wash cycle.

Leave it on cold fill as it's desgner intended.

something different- washing machines. - concrete

Thank you chrism and bromptonaut, very well made and sensible points. It just shows what first seems logical isn't always the case. I knew I would get the answer from the forum. I shall connect it as a cold fill after moving it. Many thanks to one and all. Cheers Concrete


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