Well, Ray,

As usual, you've contributed lots of opinion and not much substance.

The manual of the machine isn't "my opinion". Is it?

We will follow the science. We won't look to the facts, unless they support the science to which we understand to be true. If the facts get in the way of the science, we will refer you to the science that supports our facts. Only the "real" facts will be considered after we follow the science that supports our facts.

There is no substance in the manual of the machine. Reading it would be useless?

Is that what you're saying Mr. Ross?

The ignorant FUD here is quite amazing. HPCD's have been around for about 25 years and are growing in popularity, particularly in northern Europe. I'm not aware of any rash of houses burning down or ANY houses burning down for that matter.

They are the most energy efficient mechanical dryer available that I'm aware of (with line drying overwhelmingly being best for energy, longevity of clothes, and freshness).

They are more energy efficient and with better payback in cooler climates. (I think the ideal would be a vented HPCD that vents inside when heat is needed in the house and otherwise to outside.)

I'm not aware of any data on HPCD's being less reliable than condensing or heat vented dryers. As with any appliance there are good and poor quality manufacturers.

Regardless of what dryer someone has, it's a good idea from an IAQ standpoint to have ventilation in the laundry room to remove VOC's, PM and other harmful gook.

The recommendation in the Energy-saving tips section of the Miele user manual regards to ventilation of the room in which the machine is installed has an IF ... IF other heat-producing appliances are operating in the room with the dryer [thus increasing the temperature of the space substantially above what it would be with only the dryer operating], then additional ventilation is recommended to increase the energy-saving aspect of the dryer [which by nature of design claims to save up to 60% of the energy usage vs. a non-heat pump dryer]. Being a non-vented condensor dryer, it doesn't blow conditioned (heated or cooled) air out of the house and pull in makeup air, and power-ventilation of the room isn't normally required for the machine to operate properly.

Condensor dryers are not a new thing. They were produced in the 1950s and 60s both as stand-alone dryers and for the drying process in single-machine washer/dryer combinations. Some were air-cooled, some used a cold-water mist/spray to entice the condensation. Some collected the condensed moisture in a pan that the user dumped after the cycle. Others (such as the water-cooled models) had a pump that drained the cooling-spray and condensed moisture during the cycle. Frigidaire was known for their Filtrator models. Maytag had a condensor model. GE and Bendix/Philco were popular for washer/dryer combos. The heat-pump aspect is new vs. those earlier designs.

Immediate "expertise" about something one previously knew nothing about isn't gained from reading online manuals. The risk of further misunderstanding and confusion is clear. The very first comment after the original post says it all.

I guess you didn't realize they put an error code in the machine to tell you what's wrong.

You can run to google if you can't read the manual. Imagine that?

I can only guess what the "F" stands for in that error code description... use your imagination.

Mmmmwhahaha, mmmwhahahahaha. We're going to beat this horse to death... he's going to drink the water yet, If I have force it down his throat.

I find it very funny... if you own one of these you will do anything but laugh about it.

#Should have read the manual. It's as simple as that. So much fun.... I love it.

There's the answer ... F66. It should have been F666 ... an unFortunate coding Failure by Miele's engineers.

My dryer's code for Airflow Restriction is F16 ... leastwise it includes an F and a 6.

@Bongo, 1) do you already own and have been using this dryer or 2) are you buying it for use at the new home? If 1, have any F66 situations occurred thus far? If 2, are you prepared to handle an F66?

@dadoes yes, i currently own Miele heat pump dryer, no issues at all. It works great, i love it. To be honest, i would rather own a Miele dryer rather than Samsung refrigerator which we had to repair several times in the same time we owned Miele.

I love Miele stuff, have several including a washer (20 years old) and a dishwasher that both work better than any we've ever had.

My kid loves having a (non-Miele) heat pump dryer. The home is all electric and they installed solar panels. There's no natural gas connection available.

Enjoy your dryer. Are you sure it wouldn't work better (and might you have less lint flying around the house?) if you added a ducted vent to the outside? ;-)

There's the answer ... F66. It should have been F666 ... an unFortunate coding Failure by Miele's engineers.

yeah I could have had a field day with F666 code. LOL.

Miele certainly covered their bases. If there weren't issues with ventilation, they wouldn't have included a code to tell you that. You get that by: reading the manual... or as it were by searching Google.

So my non-substantive posts have turned into? ________________.

Maybe you curse me if you get the dreaded "F" code? I've had worse, so I'm ok with it. I'm sure it's only one of many codes you might get. The more loads you need to do, the less maintenance and care you think you need, the quicker the end will come.

But what else can you do with money, besides blow it? In some cases the problems you have in life only prove that you're still alive.

A train wreck.

The OP replied above confirming that they already have a Miele heat pump dryer and "no issues at all. It works great, i love it."

Airflow restriction fault codes have no direct relation to Miele. Some other dryer brands also have airflow fault codes. My dryer is not a Miele or a heat pump / condensor unit. I've had an incident of the airflow restriction fault (by what mechanism does it monitor that?). Two parts were required, no need to call a servicer, I'm handy that way (say whhaatt!? a homeowner can't possibly be skilled in appliance repair, that requires training and skills!).

I had kind of assumed the OP was familiar with the dryer tec from the get-go, since the question was abuout additional venting/exaust when there is also going to be a window in the room. Glad to have the additional knowledge that the OP is indeed familiar with the dryer tec, and happy with it.

I still think having an exaust fan installed for if needed isn't a bad idea. It still does depend a bit on how that window would function if it was open on the regular. If it works as an exhaust, that's great. if it's working as an inlet or as dead air, not so great.

A train wreck.

The OP replied above confirming that they already have a Miele heat pump dryer and "no issues at all. It works great, i love it."

Airflow restriction fault codes have no direct relation to Miele. Some other dryer brands also have airflow fault codes.

Yes, of course. It's probably recently new. Who is not going to love a new appliance?

That can be said of "anything" pretty much. It's new. It works. No muss no fuss.

But how does a "heat pump" operate that is different from electric resistance heat. Air flow restriction fault codes have no direct relation to Miele... absolutely, I'm not just here picking on Miele for that sake.... it can be summed up more or less in "care and maintenance" which is also a part of "any manual" for anything you buy pretty much.

Lint is dirt more or less, what does lint or dirt for that matter do to air conditioners or heat pumps in the normal world outside of clothes dryers? The air conditioning cycle whether it's a heat pump or air conditioner require "WHAT" to operate properly? Remember we are talking about a heat pump being used as a way to dry clothes.

There is dust / dirt in the air all around you. Why you use a filter for your HVAC system?

Use wise it's going to take some time for a clothes dryer. Average household size in the USA is around 3.15 members. How many loads of laundry you going to do with an average of 3.15 members?

BUT, how they push this thing is it's energy efficient. So maybe your household is larger. Are you doing laundry loads every other day? Well "care and maintenance" is going to get ugly pretty quick under those use conditions.

Maybe if you're doing 3 or 4 loads of wash a week it lasts 15 years with no muss or fuss. See I'm not a psychic or fortune teller, I can't tell you the future exactly... but I can show you the future "may not" be so rosy. The fault codes are there for a reason. The manual is there for a "reason" --- read it.

Ray's non-substantive reading material, not written by Ray. (The Manual)

How long is the manufacture warranty? 2 years. I've also seen 3 years? So I change nothing from my previous estimation, before problems start occurring. Of those problems occurring greatly depends on "care & maintenance" AND that you read the manual, put those recommendations (from manufacturer) into practice.

Average household size in the USA is around 3.15 members. How many loads of laundry you going to do with an average of 3.15 members?

Well, Ray, you never fail to disappoint. The average household size in the U.S. in 2020 was 2.53 individuals (when a statistic is quoted to two decimal places we wouldn't say "around.") The average family size in the U.S. in 2020 was 3.15 individuals. Those are both simple statistics, but they are different. You can't keep them straight, but we're supposed to trust you as some sort of engineering fault analysis guru? C'mon man.

What is an "average" how do you determine an Average? Let's argue for the sake of arguing?

Suzie has 11 apples

George as 3 apples

Carl has 1 apple

Fred has 1 apple

Jenny has 1 apple

Buddy has 8 apples

What is the "Average" number of apples that each person above has?

@Bongo, what is the age of your current newfangled heat pump dryer? Do you run 40 loads per week? 10? 3? How often do you clean the plinth filter? How often do you clean the drum filter?

@dadoes i think we bought ours in June 2018, so just over 3 years. On average 2-3 loads per day, unless we are travelling. i clean the lint filters before every load, just like we did with any other dryer we ever owned. i’ve never cleaned the plinth filter but my partner may have, i will ask but i can’t imagine its more than a couple of times (at most) during the time we owned it. also, our Miele was the least expensive model, no WIFi, no fancy cycles or anything like that.

No WIFI?

How can it send you an email to let you know the lint filter is dirty if it has no WIFI? It's a wonder the thing has lasted this long.

(3 loads a day sounds like a lot of laundry)

Ray,

You've used an incorrect statistic in your attempt to infer heat pump dryer longevity. As a consequence, you've overestimated the number of loads of laundry generated by an average U.S. household by roughly 50% (assuming each individual generates a comparable amount of laundry) and underestimated the longevity.

Charles you can argue for the sake of arguing all you want. It doesn't change anything.

I said "3-4 loads of laundry per week" the OP graciously told us they run 2-3 loads per day.

So how is it that I am "over estimating"?

I am a family of one, I can run 1-2 loads per week, just by myself. (Obvioulsy Charles, you probably don't do the laundry at your house do you?)

Statistically an air conditioner / heat pump has a national service life of about 15 years it could last longer we are talking "AVERAGES" I am not a fortune teller I am a repairer arguing with a builder of all things. I did note that it could last that length (15 years) further up. Care & Maintenace will have an effect on life of the appliance.

A callout fee from Miele I've seen could be as much as $250... so how many times you going to do that? The OP the dryer has is outside the warranty window, based on what they've said.

---------------- To The OP ------------------

So the larger question for me is that if everything is fine with this dryer what was the intent of your post OP?

Is the room this dryer sits making the room stuffy when operating? Why the post now after 3 years?

There is always a reason not that it's that important now except to be able to re-tell this story accurately to your kids and grandkids.... "Once upon a time there was......."

@Austin Air Companie new build

Bongo, ah ok. I would say depends on climate if you open the windows and it's 100F outside not going to help with a heat pump.

If the room is a more closed off room than what it's in now could pose a problem there too.

From what I could find thus far on it --- haven't seen any chart for operational design you know like temps in the home. I would assume the manufacturer designed it to run in a range of possible home temps maybe between 50-80F.? I don't know specifically for a dryer of this design.

So assuming you have air conditioning and the room is kept at a decent temp / machine is up to spec maintenance wise / room isn't too small causing air flow issues probably be ok. / Work around would be to set up floor fan to force warm air out the room while you run it.

It doesn't contain much freon little over 16 oz. R134a / compressor is probably small little window unit type compressor... from the unit I found information on, yours may be different.

"if you open the windows and it's 100F outside not going to help with a heat pump"

I think the opposite is true, I think it will help a lot.

The air in the dryer is warmed by taking heat out of the room's air and moving it to the heat exchanger through which the dryer's internal air passes. The warmer the room, the more heat is available to dry the clothes. Same is true for heat pump water heaters - heat is taken from ambient room air and is used to heat the water. Cool air is released.

A heat pump water heater works much better and more efficiently in a hot garage and or in a hot location than in a cool basement in a cool region. The hotter the surround air is, the more heat there is to easily extract and "pump".

More misunderstanding from an HVAC expert?

The heat pump dryer's heat exchanger also serves to cool the heated moisture-laden air to condense-out the moisture .... according to the description of the operation principles.

I think there are two heat exchangers or two separate sections- one's hot to heat the circulating air to get moisture out of clothes (the normal way) , the other is cold to condense out the moisture in the heated air (like an AC coil). The hot one also rewarms the air that has passed by the cold exchanger, to continue the circular flow of air becoming hot then cooled then hot again.

A heat exchanger can't be hot and cold at the same time.

The description says heated airflow exits at the rear of the heat exchanger, passes through the drum and clothes, then circulates through the front of the heat exchanger to be cooled, and back through the rear ... repeat for the duration of the cycle. Sounds like functioning of a dehumidifer within the confines of the machine.

Whirlpool has a hybrid heat pump dryer, with a regular heating element (although may smaller wattage) for speedier drying when the user desires.

My friend, I'm not reading a "description" or an air flow pattern per se, I'm sharing how I understand how they work.

A device that has a heating element isn't, strictly speaking, a heat pump dryer. As I said, a heat exchanger can't be cold and hot at the same time.

I have more respect for foreign appliance brands than for US ones. Miele from Germany is one of the best and has been for a long time but there are plenty other excellent ones. You can find European and Asian brands and innovation all over the world. I don't suspect Whirlpool has much of a customer base outside the US and probably for good reasons.

Not that it mattes but the same is true for cars.

Reference Page 19 of the user guide.

I'm not reading a user guide.

That's understandable. It is highly technical. Cited for others who may be interested.

A heat pump water heater works much better and more efficiently in a hot garage and or in a hot location than in a cool basement in a cool region. The hotter the surround air is, the more heat there is to easily extract and "pump".

More misunderstanding from an HVAC expert?

We are not talking about a heat pump water heater in this thread. We are talking about a heat pump clothes dryer. Not the same thing.

My friend, I'm not reading a "description" or an air flow pattern per se, I'm sharing how I understand how they work.

If you would read the manual it would clear up your mis-understanding. We know you can read... so what is stopping YOU?

Stop thinking... you're gonna hurt yourself Mr. Fudd.

-------------

I never put my understanding over that of an engineer, that built the machine.

I am not here to reverse-engineer something.

Here's a video that explains the airflow and refrigeration circuits. A refrigeration system has both an evaporator (low temperature) and a condensor (high temperature), yes? I'm knowing of that, although being a plebeian. Operating essentially as a closed, recirculating air circuit dehumidifier within the machine for the drying process ... simultaneously heating, and cooling the airflow to extract the moisture.

Perfect explanation, dadoes, along with showing the two heat exchangers as I mentioned. And perhaps less dependent on ambient air than I thought but I'll stick with a warmer room being better than a cold one.

When my kid moved into their new home in a hot summer region, the AC wasn't working and it took a few months to get sorted out because of a dispute between the builder and the HVAC sub. Temps in the house stayed in the 80s-90s. I never heard any comments about the dryer not working.

The massive importance of the discovery or invention (I don't know which it was) of the refrigeration cycle and its contribution to modern life can't be overstated.

Mr. Dadoes, excellent find.

This machine is an HVAC mechanics dream. When it breaks you tell the customer to bring it to your (air conditioned shop) to work on it.

The reason why room temperature is better for the lower realm is essentially two reasons.

They call the front coil a DE-superheater. The refrigerant enters this circuit "after the condenser" to make sure the refrigerant "phase change" is complete... from hot gas to desuperheated liquid. Reason 1, complete.

How do you de-superheat something? Draw in "cooler" air, not warmer.

The compressor? how do you cool that? There is only slightly more than 16 oz of refrigerant in this machine. Extremely low charge. (notice the compressor sits in the "air stream" behind the de-superheater coil.) Reason 2, complete. (If compressor over-heats what happens? I bet there's a "fault code" for that... the fan fails or the desuperheater coil gets caked with dirt.)

Anyway good find Dadoes... does a good job of explaining the process. Here's a picture I took to highlight a few things. This de-superheater is talked about around the 2:15 second mark of the video.

"This machine is an HVAC mechanics dream. When it breaks you tell the customer to bring it to your (air conditioned shop) to work on it."

You can be sure that's not the case. Miele is a premium product and it treats customers accordingly. It may have changed but for years they had their own in-house technical services teams in major markets.

I had a problem a few years ago with my washing machine. I called Miele, a service call was scheduled. The problem turned out to be a water-diverter valve that was too heavily caked with hard water deposits to function. It was replaced, the guy had the part on his truck. No charge for the service call, no charge for parts or labor. The thing was more than 15 years old.

If they don't still do this in-house, any contracted service companies will be well trained and follow strict rules. After all, it is a German company, precision and attention to detail matter.

Why would a heat pump dryer be any different than a refrigerator for repair? Appliance servicers are called for those, not HVAC engineers.

Why would a heat pump dryer be any different than a refrigerator for repair? Appliance servicers are called for those, not HVAC engineers.

Different application, different design parameters. A refrigerator isn't a heat pump, it's more designed to run like a freezer with special controls to "cool" or refrigerate the box opposite the freezer compartment. (There's a defrost circuit on a refrigerator, not on a heat pump clothes dryer as an example of differences.)

In trade school we studied refrigerators... so I had the choice to take that path if I was so inclined. HVAC/R is a very large field. (But you must be good in more ways than one, especially when often ridiculed by those who are only on the planet to look down their nose at you. You know who you are.)

When I went to HVAC/R trade school things weren't separated from HVAC to Refrigeration. I chose to follow the path of HVAC. I could have also decided to do refrigeration as well. In Texas licensing requires you to have the skills of what you choose to do. I could have chose to specialize in refrigeration / freezers etc. I merely chose not to.

At the end of the day it's merely understanding the application for what is intended. The PT chart doesn't change any just because it's refrigeration or heat pump.

When I went to HVAC/R trade school things were much simpler. It was the mid 90's. To cut school costs there might be programs now that separate refrigeration from HVAC. I don't know. That was over 26 years ago.

I've fixed family car AC's / mine and my father's before his passing. It's simply understanding how things operate / temperature pressure relationship. Understanding design differences.

I prefer to do HVAC and specialize in residential systems for the home. I only ventured into this thread because of? Re-read the thread... or read the "manual". Everything you need to know about Miele heat pump dryer is here in this thread. Would it be that way if I had not gotten involved? "probably not".

There is a lot of terrible misinformation in this thread. Particularly by people with absolutely zero experience with H/P Clothes dryers! The most egregious posts, not unexpectedly, is by the spammer seeking to draw customers to his company by repeatedly advertising his locale while really not adding value to the thread!

"Everything you need to know about Miele heat pump dryer is here in this thread. Would it be that way if I had not gotten involved?"

You came to this thread never having heard of a heat pump dryer. Your first and subsequent sometimes prevaricating comments make that very clear. I don't think any readers who have happened along think otherwise, nor would agree with your comment quoted above

AA, I knew how a heat pump dryer functions before you brought up any details about it ... before I perused the user manual, before I found and posted the video ... which I shared so other readers would understand it who perhaps aren't aware.

Appliance servicers of course may also be trained on refrigeration. The small towns in which I've lived, a homeowner would not call Dave's Air Conditioning and Heating or Kevin's Air Conditioner Service to get their refrigerator (or their heat pump dryer) repaired. They'd call Tony's Appliance Sales & Service or Herbert's Appliance Sales & Repair. Likewise, Tony's or Herbert's would not be called to repair a central A/C system because that isn't their business model.

"AAC: But you got here 'late'."

LOL, that's just what you saw from afar. I followed this discussion from day 1 of it. I've taken to usually watching discussions of interest for a while for the instigators of the train-wreck effect to arrive before commenting, if I decide to do so.

AAC: But you got here 'late'."

LOL, that's just what you saw from afar. I followed this discussion from day 1 of it.

We're in the fact check era. I could never get away with a comment like that... so you can't either.

Austin Air Companie, why do you keep picking a fight and being rude in this thread?

Austin Air Companie, why do you keep picking a fight and being rude in this thread?

Everyone is "entitled" to their opinion... but I am not entitled to mine?

So you are picking fights and being rude because you feel entitled to do so? Ok, so.. why do you feel entitled to pick fights and be rude in this thread?

AAC, here's your fact-check.

The topic says "Posted by Bongo July 6, 2021"

My browser history indicates I read it on 7/6/2021 8:19 am.

Even better ... all the viewing history for the topic .... bottom-up on each screen capture, 7/6/2021 8:19 AM to current (not including this reply).

I wouldn't bother, dadoes. It's enough to point out any paticipant's comments that are obviously pretend knowledge or new to them information found from an internet search. Such instances are clear and obvious for readers to see.

So you are picking fights and being rude because you feel entitled to do so? Ok, so.. why do you feel entitled to pick fights and be rude in this thread?

LOL, I said that was your opinion. My opinion is that I am not rude, nor am I picking fights.

If you constantly worry about what others "might" think... well I choose not to live in that bubble. I don't concentrate on trying to please people that are not "pleasable" under any circumstance.

So now you are doing exactly what you are claiming that I am doing... being rude and trying to pick a fight with me. Interacting on a forum board is a "two way street". I am just pointing out the *error* in your thinking. (You can of course disagree if you want, you have that right just as much I have rights too.)

If what I say offends you... well I'm offended that you're offended = call it even.

I am not here to tell you what you want to hear. I am here to tell you "how it is." You are free to not like it. How a con works... tells you everything you want to hear. Itching ears love it... sooner or later you realize the fallacy of that. (The truth is the truth for a very important reason.)

Honey do these jeans make me look fat? Let's lie? so you understand the point... because thus far everything seems to fly right over your head.

Even better ... all the viewing history for the topic .... bottom-up on each screen capture, 7/6/2021 8:19 AM to current (not including this reply).

Very clever... but there is no fact that says what side of the "brick wall" you were on.

So I'll give you this for your fact check: Partially true but MISLEADING information

---------

Pretend Knowledge: ha, ha, ha. Mr. Fudd must be writing a book? Sub header would be "I refuse to read a manual to further my understanding of what I clearly do not know..."