I have a 3-month-old Miele W3033, and yes, it uses cool water for prewashing.

I think the reason for this is because some stains are "set" by heat... this allows the machine to do a sort of "profile wash," allowing enzymes, etc., to do their work in cool water before the main (hot) wash begins.

I also use prewash ("heavy soil") setting on dusty, dirty gardening clothes. Cool water does a fine job rinsing away surface dirt before the main wash.

Hope this helps. I think your machine is functioning properly.

Yes Cryptandrus is right. Miele uses cool/cold water for the Prewash cycle! Many stains are "set" by warm or hot water (especially sanitize temp water). Prewashing with cool/cold water allows many stains to break down, and also effectively rinses away dust and dirt, to allow the main wash cycle to do it's job. If you've selected warm, very warm, hot....for the main wash, after the prewash is complete, then the water for the main wash cycle will be the temperature you selected! It's all good!

Thanks for the follow-up guys. I could have sworn it just used the same temperature, in fact I remember people discussing it on here, upset the pre-wash wasnÂt cold. The whole profile wash thing was brought up and everyone went round and round about it. Maybe it was just another Ambein induce hallucination of mine. Anyway IÂm happy it doesnÂt do hot pre washes, I love these machines.

My experience is to the contrary. I was using Extra White cycle on HOT with Heavy Soil (pre-wash) ON. The pre-wash DID pull a significant amount of hot water - I could tell because my hot water line has air bubbles which make a sound. The porthole glass also steamed up on the inside of the drum, which wouldn't happen with only cold water.

I don't believe all pre-washes are cold only on the W48XX series machines.

sshrivastava

I knew it, I just knew it. Using the same cycle as you, my machine pulls in mostly cold water now on the pre- wash, a little hot, but mostly cold. Either IÂm retarded or there were a few changes made when the Miele techs were here, possible both. They said there were no updates so IÂm perplexed at this change.

Wow, this just goes to show how erratic and different W4840 and W4842 machines can vary. It must have to do with Software versions and production dates.

My Pre-Wash (Heavy Soil) is always Cool/Cold. I have tried it with almost every cycle offered...and I have never had a heated prewash. I can easily touch my hot and cold water valves behind the washer, and during the Pre-wash (Heavy Soil) only the cold hose has water flowing through it. Everytime!

On my W4840 I've seen the heater activated during prewash. But it only stays on for a little while, maybe until Cold or Warm temperature is reached.

During the prewash my 10 y.o. Novotronic heats the incoming tap cold water up to 30°C/86°F whatever temp you choose for the main wash (boilwash included).

My brother's W 3264 does the same too.

The same applies to the soak option.

Otherwise my stoneage sensor-electronic heats up to 50°C/120°C (obviously only if you choose 50°C or a higher temp)
cause back then in the 80s enzymes worked better in the 105-130 °F range

If the reason some of your machines are heating the water, maybe it is because your tap water is cooler than what Miele deems "cold" at 86F..as hidroman stated! Where I live, in the Western part of California, West end of Los Angeles...it is VERY hot. We are on day 5 on almost 100F, and from like mid June to late Oct...most days are 95F to 105F. So...my tap water is almost always above 86F. Sucks when you want to take a cold shower...it's always warm.

My showers are HOT here in Phoenix! Been 110-115 the last few days. Whew! Mold doesn't stand a chance.