Thread Number: 88965  /  Tag: Modern Dryers
Miele TWF640 - Drying temps
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Post# 1135300   12/4/2021 at 19:54 by henene4 (Emden (Germany))        

There have been some posts on here recently that expressed dismay with their appliances of a certain brand.
I'm no brand loyalist, and I don't want to say that people are wrong about their bad experiences.
Yes I have my preferences, but I can put these aside.

What I can't stand - and that comes from both a professional and hobbyist standpoint - is exaggeration of such bad experiences with stuff that is just factually not true.
Not only not true - that basically can't be true just by the way that these things work.

If a person comes to our store with an issue about their appliance I am very happy to help.
If they start saying stuff that can not be true, that is counter productive for both of us. I have to somehow then weigh everything said with that fact in mind which in turn will make it more likely that I will or can't help them.
You know, somebody walking in and saying their phone screen just shattered by itself and demanding a fix under warranty will just not get any second more of my time than somehow necessary.

And as a hint to anybody not having cought on:
I only work at a service desk in a store. I have to know many things somewhat well and I can already filter much of the BS out.
Trying to claim anything not backed up by fact to the service of a manufacturer that has access to the literal specifications of EVERY aspect of that product will yield nothing but them NOT helping you.

One person on here in particular claimed their heat pump dryer from the T1 series shrank their clothing.
That it got very hot.
Which just isn't true - can't be true.

But that person insisted they were right.
But they aren't - and I knew that.

So I ordered a cheap digital thermometer off of Amazon.
You can get a simple one that just measures the temp with a remote probe that is water tight for 5 bucks.
I wanted a min/max function in case I missed the max temp - so I did not have to sit around all the time. That came in at 8 bucks and even included a temp sensor in the display unit.

These things are just glorified inside/outside thermometers you can hang out your window.
Thus they are water tight and read up to 70C usually - which is perfect for DWs, most wash and dry cycles.

This allows me to monitor the max temp of such cycles on all of my appliance.

So I will be placing that sensor in the fluff filter of my dryer on some cycles.
Especially, I'm popping that sensor through the opening for Mieles dryer scent flacons on the left side, closing that slider as far as possible and routing the wire to the right.
While that won't be exactly the temperature in the laundry, most dryers monitor the clothing temp right around there.
So it is close enough for the purpose.

For my first load, I ran my large darks load through the darks cycle on my washer.
The load consists of 2 pairs of jeans, 4 pairs of sweat pants and 3 sweat jackets.
On that cycle, these items get a medium/short 1200rpm spin. Usually I wash them on Cottons, where they would get a longer and faster spin, but I wanted to extend the dry time a little.
I did NOT select the low temp option like I usually would.

And - surprise - the dryer barely reached 60C. Which isn't cold but far from shrinking hot.
The first check in was at about 1:05h in the cycle and the dryer was just short of 50C/120F.
Next check in was in the extended drying stage that happens at the end of the Jeans cycle. It hadn't reached 60C yet.

I missed the actual point the heat pump shut off, but it was only a few min before the I took the final pictures showing the max temp reached - which was 61.8C.
This is the hottest running cycle/load combo I think I ever have in day to day operations and saying the max the load reaches was 65C/150F or less is reasonable.

I'll be running an even larger load next week but from experience that load will run cooler.

If anybody has any suggestions on cycles or loads I should try I'll see what I can do.

But no.
These dryers don't get very hot.
Sure they can shrink items - but these items would have shrunk in any other dryer aswell.

Rant over.

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Post# 1135301 , Reply# 1   12/4/2021 at 19:55 by henene4 (Emden (Germany))        

Oops,the pics are in revers order. Sorry for that.

Post# 1135327 , Reply# 2   12/5/2021 at 10:25 by Tomturbomatic (Beltsville, MD)        

Thanks for the data. Do the dryers have a heating element to warm no iron fabrics to the optimum wrinkle relaxing temperature of round 160F? It is not that hard to heat dry clothing to 160F especially in a closed environment like this dryer. The small "portable" dryers sold here can do that and the Maytag Halo-Of-Heat dryers heated the load to 160F after it was dry when set for the permanent press cycle.

Post# 1135334 , Reply# 3   12/5/2021 at 11:35 by henene4 (Emden (Germany))        

I'll run a test to see what the max temp it can get to is.

Might be delayed a few weeks due to some family stuff, but I'll get around to it.

Post# 1135398 , Reply# 4   12/5/2021 at 19:36 by Moon1234 (Wisconsin)        

Hottest temp would be with extra dry setting. As laundry becomes moisture free the heat has no liquid to absorb and so the clothing would get hotter. These machines I donít believe can get that hot. The condenser would be themoregulated to prevent it from getting too warm. The compressor would be shut off and the refrigerant could not overheat. There is also a small evaporator with a fan to remove any ďexcessĒ heat when the compressor is running and the load is not large enough to need all of the heat.

Pretty sure this dryer would top out at 150F max. Some textiles at that temp may shrink. Miele recommends a setting of normal which is cupboard dry. This helps prevent heating dry clothing. Normal Plus is a smidge over dry. Extra dry is for people used to cooked clothing or very bulky items where the center may be moist but the parts touching the sensors in the paddles are showing dry.

Post# 1135412 , Reply# 5   12/5/2021 at 23:49 by richnz (New Zealand)        
We have shrinkage

Only with certain items
Peter Alexander pajama tops shrink.

The sleeves get short and the body shortens too.

Luckily they are not my pajamas.
We have a Miele heatpump drier.

I blame the other half. She likes to dry using the Cotton setting.
I prefer all clothing dried using the Automatic setting.

They are quite elasticated pajamas tops.

As I am not suffering, I don't mind at all.


Post# 1135414 , Reply# 6   12/6/2021 at 00:28 by littlegreeny (Milwaukee, WI)        
I wonder what I'm doing wrong...

littlegreeny's profile picture
So just got my T1 and running the normal cycle with it set to extra dry and even having the dryness set to max in the settings when the dryer is finished and I open the door my glasses fog up and there is a slight moistness to the laundry. The laundry seems to be dry within a few minutes of coming out though. And it's definitely warmer than I was expecting. Is this how it's supposed to be?

And my new dryer made all my laundry stink like plastic mixed with machine shop. I think it was from it being new as the smell is dissipating as I use it more. So far I'm not very impressed with the dryer.

Post# 1135421 , Reply# 7   12/6/2021 at 03:41 by Logixx (Germany)        

logixx's profile picture
I ran a load through my dryer last night and, yes, my glasses fog up slightly as well when I put my face right in front of the door right after opening it. Increasing the cool-down time (or cool-down target temp with Miele dryers) helps in my case. In fact, I did add an extra air dry cycle on my regular condenser dryer, too. Clothes were cooler and residual moisture removed.

The thermometer I use goes up to 158F. There have been more then one occasion where it would display "max" because the dryer got hotter than what it could measure.

Post# 1135426 , Reply# 8   12/6/2021 at 06:04 by Tomturbomatic (Beltsville, MD)        

The slight remaining moisture in the atmosphere of the cylinder at the end of the drying cycle was a situation encountered with early low air flow dryers and condenser dryers in the late 1940s, the 1950s and into the 1960s. Users were instructed to check fabrics for dryness by pulling them out of the humid air of the dryer and shaking them in the room air to avoid over drying by having them feel moist when they were indeed, dry. It is just one of the characteristics of condenser dryers.

Post# 1135439 , Reply# 9   12/6/2021 at 09:08 by littlegreeny (Milwaukee, WI)        

littlegreeny's profile picture
Thanks Alexander and Tom for your replies. I don't think there is a way to increase the cool down time on my dryer but am glad it seems to be functioning as it should. I knew there would be a learning curve and am sure it's going to take a little time to figure everything out.

Post# 1135457 , Reply# 10   12/6/2021 at 15:11 by Logixx (Germany)        
Cool down target temp

logixx's profile picture
Yeah, you're right. Another option not available on the US firmware. 😒

Post# 1135879 , Reply# 11   12/11/2021 at 09:50 by logixx (Germany)        

logixx's profile picture
Did some testing in my Series 8 Bosch with a medium load of dark cottons. I used the Cotton cycle with the normal dryness level and two increments up. The initial time displayed was 2:52 hrs. Here's the temp each ten minutes of the cycle:

00 min. - 24C | 75F
10 min. - 30C | 86F
20 min. - 36C | 97F
30 min. - 41C | 106F
40 min. - 44C | 111F
50 min. - 50C | 122F
60 min. - 56C | 133F
70 min. - 62C | 144F
80 min. - 60C | 140F

Interestingly here, the temp never got that high; I would have expected more, especially since the heat pump basically kept running until the dryer shut off.

Around 30 minutes into the cycle, the display switched from just "drying" to "iron dry" and the cooling fan started cycling on and off. The first flush of the condenser also takes place here and the timer finally dropped from 2:54 hrs. to 1:01 hrs. remaining. I think only Miele had a worse timer many years ago that only lit up and counted down during the timed cool-down.

Around 70 minutes into the cycle, the heat pump shut off for the second time for the final two flushes, thus the slight temperature drop. I added my usual 20 minute air-dry cycle, which brought the temp down to 43C or 110F and eliminated any lingering humidity in the drum.

Post# 1135881 , Reply# 12   12/11/2021 at 09:54 by Logixx (Germany)        

logixx's profile picture

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Post# 1136179 , Reply# 13   12/14/2021 at 11:41 by lavamat_jon (-)        

I am glad you have started this thread, and pleased to hear that your dryer works for you.

I donít use the dryer much as I prefer to naturally dry laundry, but always put towels in the dryer so I had the opportunity to dig out my temperature probes and test it this week. Attached below are the temperature readings. I didnít pay a close eye as I was working whilst the dryer was on, but you can see from the pictures that the highest reading I caught it at was 66.8į which was towards the end of the cycle with around 15 mins remaining from memory.

Final cycle time clocked in at just under two hours for a full 9kg load of towels, spun at 1600 in the Miele W1. They normally take around 10 minutes on average less if Iíve washed in the Siemens, but that does a longer spin at max speed.

Again - in my own experience the facts are that my T1 dryer shrinks clothing - which I never encontoured with my older Edition 111 model. Itís not a bad thing that the heat pump itself is very efficient at creating heat in the load, but unfortunately it does mean t shirts, jeans etc are more likely to shrink, much like they would do in a more traditional dryer. I cannot trust it to dry everything like I did with the Edition 111 (which was useful in my previous flat where I wasnít supposed to dry laundry indoors).

The new models do have a DryCare 40į option to safely tumble dry most laundry, so knowing Miele like I do I canít imagine they would introduce such an option if there wasnít a problem to solve in the first place (like the Bedlinen cycle).

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Post# 1136214 , Reply# 14   12/14/2021 at 22:34 by mielerod69 (Australia)        

mielerod69's profile picture
Hi everyone,
I too have ordered a temperature sensor as I'm curious how hot my T8929WP gets during drying.
I looked at the type of refrigerant used in the two dryers in question. The TWF640 uses R290 gas whereas the TCR860 uses R450a.
The use of different refrigerants can have an impact on drying temperatures. As mine has R134a refrigerant, I'm interested to see what temperature it will reach in a drying program.

Post# 1136257 , Reply# 15   12/15/2021 at 17:49 by richnz (New Zealand)        
Here is what is happening inside mine

Its on the Automatic+ program

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Post# 1136632 , Reply# 16   12/19/2021 at 23:16 by mielerod69 (Australia)        
Drying temperature Miele T8929WP

mielerod69's profile picture
Hi everyone,

So I did some temperature tests with my Miele heat pump with a load of towels consisting of 2 bath sheets, 2 bath towels, 4 hand towels, and a bath mat. The program was Cottons Extra Dry. Total running time 90 min.
These were the temps at 10 min intervals:
00 min. - 27C
10 min. - 34C
20 min. - 39C
30 min. - 43C
40 min. - 44C
50 min. - 46C
60 min. - 46C
70 min. - 48C
80 min. - 53C
90 min. - 56C

Interestingly before the towel run, I ran a 3 kg mixed load of items on the Automatic Plus Normal program and the temperature profile was very different.
0 min. - 24C
10 min. - 30C
20 min. - 40C
30 min. - 50C
40 min. - 55C
50 min. - 59C
60 min. - 64C

Did I put it down the higher temperature to the smaller load? Not sure. Anyway, I will test the Automatic Plus program with towels to see if it gives the same temperature profile.

Post# 1136634 , Reply# 17   12/19/2021 at 23:28 by mielerod69 (Australia)        
Did the same in my dishwasher

mielerod69's profile picture
If anyone is interested, I did the same in my Miele G7915SCi dishwasher as well. It's in that thread.

Post# 1136657 , Reply# 18   12/20/2021 at 09:23 by Logixx (Germany)        
Smaller load = higher temp

logixx's profile picture
I had the same thought yesterday when a small load (fitted sheet, pillow and duvet cover) was warmer than expected after the drying cycle. 🤔

Post# 1136714 , Reply# 19   12/20/2021 at 20:07 by richnz (New Zealand)        
How does a drier measure load size?

These smaller loads leading to higher temperatures.

I wonder what constitutes small too.

Post# 1136897 , Reply# 20   12/22/2021 at 15:50 by GELaundry4ever (Killeen tx USA)        
cottons program

How hot does it get on the cottons program?

Post# 1138344 , Reply# 21   1/3/2022 at 23:04 by henene4 (Emden (Germany))        
Back home did some testing

My regular whites load (about 25 T-Shirts plus underwear and socks for 2 weeks) today dried in just about 80min and peaked at a whopping 49C - yet was totally dry.

I purposefully overran a time cycle by a lot with a very small load and the temp leveled out at just about 65C.

Post# 1138345 , Reply# 22   1/3/2022 at 23:12 by henene4 (Emden (Germany))        
Self limiting characteristics of a heat pump

A heat pump with a certain type of compressor and a specific amount and kind of refrigerant will alway reach a state of equilibrium.

The hot, high pressure side of the system will reach a certain pressure and temperature at which the refrigerant vapor can still effectively condensate.
The cold, low side will reach a certain temperature where all the liquid still evaporates.

The metering device which seperated high from low pressure can only allow a certain amount of liquid by maximum.

If the refrigerant gets too hot, it won't condensate at the maximum pressure on the high side anymore.
That means there is less heat deposited into the drying air.
That slows down the heat transfer to basically negligible levels.

Thus there is a certain temp at which the heat pump can't raise the temp anymore.

And for most dryers I used so far, that is around 60-70C.

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