hot and cold washing machines

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hot and cold washing machines

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Rikki

Joined: 09 Jun 2005
Posts: 35
Location: Bucks

Posted: Sat Jul 16, 05 9:55 pm Post subject: hot and cold washing machines
Why are all new washing machines cold only? (I'm installing a solar domestic hot water system and want to use my freely heated water to do the washing, but not for all the rinse cycles.)

Blue Sky

Joined: 30 Jan 2005
Posts: 7658
Location: France

Posted: Sat Jul 16, 05 10:08 pm Post subject:
I hear that a large bucket serves the purpose very well. Be careful with re-usable nappies tho'

nettie

Joined: 02 Dec 2004
Posts: 5888
Location: Suffolk

Posted: Sat Jul 16, 05 10:46 pm Post subject:
Bring back twin tubs, that's what I say!!

dougal

Joined: 15 Jan 2005
Posts: 7184
Location: South Kent

Posted: Sat Jul 16, 05 11:22 pm Post subject: Re: hot and cold washing machines

Rikki wrote:

Why are all new washing machines cold only?

Dunno about *all*... BUT with the machines using ever less water, chances are that the water won't "run hot" before the machine is 'full'. The problem is the volume of water in the pipe between hot tank and machine being so large that the efficiency takes a massive hit. Filling it with cold water from the hot tap, and then refilling the pipes with water that you have invested in heating, doesn't make much sense.
I know that if your water is solar heated (all year round) then the wasted heat hardly matters. But unless you have your hot tank is really close to the washing machine, you're not going to save much electricity compared to a cold fill only machine
But for most folk the waste of heat does matter - and that's who normal machines are designed for.
So, if there's no great advantage in hot & cold fill, the machine can be made more cheaply by deleting the hot water valve, piping and control circuitry...
And the plumbing of a new installation is less work too.

Treacodactyl
Downsizer Moderator

Joined: 28 Oct 2004
Posts: 25795
Location: Jumping on the bandwagon of opportunism

Posted: Sun Jul 17, 05 7:04 am Post subject:

Ours, a Bosch, is hot 'n cold fill. However, it only fills with hot water on the maximum 90�C wash, IIRC, which we never use. Have you looked at all the washing machines? I think some of the more expensive ones may have hot fill but then is it worth the extra money?

To solve the problem of the hot water reaching the machine you can just run the hot tap next to the machine just before turning it on?

nora

Joined: 20 Mar 2005
Posts: 1539
Location: West Yorkshire

Posted: Sun Jul 17, 05 8:56 am Post subject:
I have a Hotpoint 1st Edition 1000 and it has a hot and cold fill. It can heat the water itself but if I push in the Economy Wash button it takes hot water from my combi boiler. I've had it about 6 years so don't know if theyr'e still for sale new or not but there may be second hand ones around.

dougal

Joined: 15 Jan 2005
Posts: 7184
Location: South Kent

Posted: Sun Jul 17, 05 3:23 pm Post subject:

Treacodactyl wrote:

... To solve the problem of the hot water reaching the machine you can just run the hot tap next to the machine just before turning it on?

Fair enough for solar, but because most customers are paying for the energy to heat the water, and that's a waste they don't need. (Water conservation notwithstanding.)

Heating only the water you use, albeit by electricity, with effectively zero wastage is not a bad design decision. The quantity of water is not large, and for a 40 or 60C wash, its not being heated very much.
With good low temperature detergents, and using a 40C wash cycle, your hot tank water would actually be too hot...

Treacodactyl
Downsizer Moderator

Joined: 28 Oct 2004
Posts: 25795
Location: Jumping on the bandwagon of opportunism

Posted: Sun Jul 17, 05 3:41 pm Post subject:

For us our combi is right next to the washing machine so there is also little waste but I can see for many homes there would be some waste.

The question I have about washing machines and dishwashers etc is do they actually scale up their heating elements like they show in the adverts? Dishwashers have inbuilt softeners but washing machines don't. I've not heard of anyone who's actually had one break down due to hard water though.

dougal

Joined: 15 Jan 2005
Posts: 7184
Location: South Kent

Posted: Sun Jul 17, 05 4:15 pm Post subject:

Treacodactyl wrote:

The question I have about washing machines and dishwashers etc is do they actually scale up their heating elements like they show in the adverts? Dishwashers have inbuilt softeners but washing machines don't. I've not heard of anyone who's actually had one break down due to hard water though.

There are different aspects, but yes washing machines do suffer from scale build up. HOWEVER
Dishwashers have softeners, 4-in-1 tablets, etc because the wash performance, particularly on glass, can be very very easily critically assessed! That is of more immediate concern than scaling up of the element...
And again its a matter of temperature. Lower temperature, less scale.
But anyway, element scale buildup rarely causes the machine to *break down*. It will cause the water to be less effectively heated, but this will be progressive and insidious. IMHO, its pretty rare these days for elements to be designed such that they do overheat to the extent of "burning out" because they are blanketed by scale.

Rikki

Joined: 09 Jun 2005
Posts: 35
Location: Bucks

Posted: Mon Jul 18, 05 6:27 am Post subject:
My old house had economy 7 so I always did the washing at night.

tawny owl

Joined: 29 Apr 2005
Posts: 563
Location: Hampshire

Posted: Mon Jul 18, 05 8:32 am Post subject:

dougal wrote:

But anyway, element scale buildup rarely causes the machine to *break down*. It will cause the water to be less effectively heated, but this will be progressive and insidious. IMHO, its pretty rare these days for elements to be designed such that they do overheat to the extent of "burning out" because they are blanketed by scale.

I agree, and even if they did, have you seen the price of supposed anti-scale product such as Calgon? They cost about 7 quid for 30 tablets or about 23p/tablet, thus, say you're doing an average 4 washes a week, that's 208 washes/year, or �47.84 spent on Calgon tablets. Considering the average life of a washing machine is supposed to be 7 years, you'll have spent �334.88, which is the price of another (v. good quaity!) washing machine. Not to mention putting yet more chemicals down the drain. There's an interesting article on hard water here: https://www.washerhelp.co.uk/limescale.html#cl_q7

IMO, if you're really concerned, and if a test shows your water's very hard, then you'd be better off with an Aquamag or something similar (be careful though - we had one of these, and once it was on for a while, the pipes started to leak, presumably because it had dissolved the limescale gathered in the joints).

Rikki

Joined: 09 Jun 2005
Posts: 35
Location: Bucks

Posted: Mon Jul 18, 05 3:58 pm Post subject:
I use "calgon" equivalent because, I think, it means you can get away with less detergent, and that the chemical impact of calgon is a lot less than washing powder. It also means there aren't the same cost implications. Any chemists out there know the truth? Good link - thanks.

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