brand new Bosch Home Professional tumble dryer made weird knocking noises. What was the problem ?

[wholelottared]

Hello everyone. I've been following this forum quietly since years. I always loved reading it, and was grateful about how helpful everyone here is. Recently I experienced something bad that led me to finally create an account here and make this post haha. So this will be my first post, I'm sorry if I make any mistakes in the post structure etc.

This will be a really long story/post, but I know how helpful and dedicated people here are so I'm sure there will be someone who can help me too. Thank you so much.

So, I never had a tumble dryer before, and I finally wanted to buy one. I've been using a Bosch Home Professional washing machine since years, and i'm still in love with how beautiful it looks, and how it's programmed, etc. So of course a brand new Bosch Home Professional tumble dryer was my first choice, since it had the matching design, and I just love how modern their display looks etc. I knew some of the negatives of the Bosch dryers such as no reverse tumbles etc, but I still went with it.

I had three main criterias to choose a dryer, and this one had it all so I bought it.
1. Being heatpump & being A+++
2. Being 62db or lower
3. Good quality & good design/feeling

I ended up buying this Bosch A+++ Home Professional WTX87EH0TR model: https://www.bosch-home.com.tr/urun-...ri/isi-pompali-kurutma-makineleri/WTX87EH0TR#

I live in Turkey, so it has the WTX87EH0TR model code, but the same device is available in other countries too. For example in Poland it'S WTX87EH0PL, in Europe it's WTX87EH0EU, in UK it's WTX88EH9GB etc etc.

The machine arrived after weeks, and I was so excited to use it. It had the 0209 FD code at that time, meaning it was brand new and just left the factory some weeks ago haha.

The first week, everything was okay. And I was in love with it.

After the second and third week, it started to make a really weird and audible knocking noise. To detail, it wasn't making the noise right after I started the machine, but as it was running and getting hotter, it was starting to knock. So it was doing this constant knocking noise only when it got hot. It drove me crazy because it was audible even when I closed the doors.

Here is a video of the problem after I finished drying some clothes, where you can hear it completely even though the drum is empty:

Video 1:

Video 2:

So I called the service, and they came to my house countless times, saying that the noise is ''completely normal'' and there was nothing else they could do. Some didn't even wait for it to run a bit, because normally the knocking noise was getting more and more annoying as it was getting hot. It made me so angry, because the device was literally only three weeks old and it was knocking. I was sure that the other people who also have Bosch dryers didn't have this noise, even the one who uses the same model as me.

So I kept contacting the service, and they took device, then called me a week after, saying they changed 2 parts of it, saying it was faulty, and they said now it's fixed. After this I was even more angry because I paid so much for this thing (it was the most expensive model) and it already went to repair.

I told them that I don't accept that repair, and I requsted my device to be changed with a new one. They finally accepted it and changed my device with a new one. So months later they accepted the exchange, and I'm still waiting for the new machine to arrive (the same model).

Thank you for reading until here, now I can finally ask my questions I guess. Some of the questions might be a bit off-topic compared to the problem I talked about, but I always had those questions in mind too so I'll ask them.

1 (most important question). What could be the reason of this sound on a brand new device? Was it really ''normal'' as the service said? Do you have any guesses where it could be coming from?

2. If this noise is really normal as they said, will my new exchanged device have this noise too? (I still don't think it's normal though because my friends who also use a Bosch dryer they all said they don't have this noise.)

3. Since my device is ''A+++'' does that only affect the ''cottons cupboard dry'' program or is it an A+++ device in general, for all programs included? Because I normally use the ''Mix'' program, since I dry cottons and synthetics together most of the time. And I fear the cottons program might damage some clothes so I use Mix instead. Is Mix A+++ too overall, or only cottons?

4. I realized that the same model in Germany (WTX87E40 and WTX87E90) has 59db rating instead, and I couldn't find any models outside of Germany who has 59db rating. The lowest one they have is 62db, which I had. What is the reason for this ? Is the same device in Germany using a better, quieter motor or something ?

5. At the first, I chose this device, because it had the ''AutoClean'' system unlike the old ''SelfCleaning Condenser'' ones. So these ones probably won't get clogged, since I can reach the condenser unlike older models. My question is, this device doesn't have that classic double filter in the door since it's AutoClean. So if I buy that double filter which is used on other models and add it to mine, would it damage anything or make the sensors etc misbehave or block the air flow? (So basically I'll make it have three filters, one in front of the condenser, two on the door, + AutoClean.) I feel like adding that additional fiter could really add to the device's lifetime, so i'm thinking to do it on my new device when it arrives. What do y'all think? Would it cause any problems?

6. To note, if my new device also makes the same noise when it arrives, I'm thinking to refund it and buy an Electrolux dryer instead.

This is all. I know it was ultra lengthy to read, sorry for that, but y'all are the only ones who can help me and answer my questions. Once again, thank you so much. I'll be waiting for the replies and discussion. Y'all can ask me any questions if you have any, and I would gladly reply.

 

[cfz2882]

keep the Bosch

probably the wheels the drum rolls on became temporarily "flat-spotted" the same thing happened to my ~2010 Asko dryer:the wheels started knocking,knocked for a few weeks,then stopped and hasn't knocked in years Welcome BTW,you live in an interesting and wonderful country

 

[mrlaundry1011]

Your device will be A+++ on any cycle, the only difference is with hybrid dryers with speed selected but this doesn’t apply to yours.

The knocking noise is frequent with Bosch models. I know someone’s who’s had to have a drum replacement, mine also knocked constantly and needed a bearing replaced at a few months old. My Beko hybrid and my partners same model now has a ‘heart beat’ thud due to flat spots on the rollers but this happens after years of use.

Personally I wouldn’t bother adding the normal drum filters, with Bosch auto cleaning the extra filters won’t really do anything but need more maintenance

 

[wholelottared]

Oh wow it's sad to hear the noise is popular on Bosch models What a weird problem. I wish I went with Electrolux instead at the start I hope my new device that's currently coming doesn't do it.

Also are you sure I shouldn't add the normal filters? With that way, I was trying to make sure none of the lint/fluff reaching the inside of the machine. By maintenance if you meant you'll need to clean more filters manually then you're right haha.

 

[wholelottared]

Are there any other ideas from other people too? Not all of my questions are answered yet haha

 

[logixx]

1) Definitely not normal. My Serie|8 is two years old now and does not make that sound. Never did. It will make the quick thumbing sound right after starting, which comes from the drum roller. But that sounds very different from what you have.

3) It's technically equally efficient on all cycles, as the heat-pump is either on or off (until the (re-) launch of inverter compressors next year).

I would imagine that the hot Quick|Mix cycle is maybe a little more efficient, as the dryer uses all the heat it generates to dry clothes quicker, rather than starting to vent "excess" heat through the bottom right. Kind of silly, when you think about it. It's like opening your windows at home when it's too hot, instead of turning the heat down. So much for energy efficiency.

4) I, too, was trying to find out how there's 59dB models. However, the exploded views of these are the same - so it's not like there's more insulation in the quieter models.

5) Yeah, the two extra filters mean more maintenance. I'd only bother if you see significant lint of the condenser.

 

[wholelottared]

Thank you so much for your reply, @logixx . I guess you can't reply to posts here so i'm writing like this. Happy to hear it's not normal, because that means the exchanged device probably won't have the noise. Also, yeah I realized that the heat pump never turns off on mine until it finishes (except the AutoCleaning stage). Does this mean are all the programs using the same temperature to dry? For example, are the Cottons and Mix programs using the same temperature to dry clothes, with only times differing between them? I could've waited a year to buy a dryer to be honest, but I didnt know Bosch was going to use inverter pumps on their next models, so I bought the current flagship device. I just checked and it looks like they're only gonna renew the Serie 8's and not the Home Professional's (with the tft screen) yet, so I would've been probably bought this same device next year too. What differences a inverter pump makes? Am I losing too much or does it not matter lol. Thank you for the replies again, would be grateful for the next replies too if someone have anything to say.

 

[logixx]

Inverter heat-pumps can change the speed they are running at. Previous TOL BSH dryers used to have ecoPerfect and speedPerfect options to either de- or increase the speed and thus heat output of the heat-pump. These new dryers will will only have the speed option, which will naturally be promoted as something brand new (just like the fact that their dryers are reversing... again).

On the current range, yemp is only controlled via the little fan in the base of the dryer. To (theoretically) prevent high temps, the fan sucks air through the cabinet and removes some heat from the dryer. It's not like on their vented/condenser dryers, where the element would run at full/half/half intermittent power to achieve different temps.

I will say that these dryers can get pretty hot. Both MrLaundry101 and I have posted temps to our YouTube Community Tabs, with some instances of over 70C during drying. Essentially, the longer the dryer runs, the hotter it gets. The small fan doesn't do all that much and the Low Temp button doesn't do a thing at all.

MrLaundry101 has more dryers in his collection and none got as crispy as the Bosch *can* get.

 

[wholelottared]

Thank you, @logixx . I'm shocked, it can even get to 70C I thought it would be more gentler on my clothes compared to other dryers since it's a Bosch and it's A+++. Looks like an another reason why I should've chose Electrolux/AEG I never had any shrinking so far so hopefully it's ok, but Electrolux/AEG ones probably doesn't reach 70C, that's too high. I'm also surprise “low heat” option does nothing at all, then why is it there and why it makes the time higher, so weird. Also I chose the “+1” drying option from settings, since +0 sometimes lefts things a bit. I was thinking to turn on the “low heat” too, but I won't after your comment.

 

[wholelottared]

Just realized I made some typos in my latest post and I can't edit it, sorry for that.

 

[wholelottared]

@logixx , I just checked your YouTube channel and saw that Mix got hotter than Cottons on your device. Is this the case most of the time? If yes, I might start using Cottons for everyday clothes since it might be more gentle than the Cottons. Also, on my device sometimes the fan at the bottom right works even on the Mix cycle. Could it be a difference on the programming ?

 

[maytag85]

I am not sure what’s causing the knocking/thumping sound but my educated guess is it’s either the rollers have flat spots on them or the drum itself is out of round. Have a friend in Michigan who had a Whirlpool 29” top filter dryer from 2009 that made a thumping sound every time the drum went around, that dryer has since been replaced with a older Whirlpool dryer from 1965 that’s been working flawlessly since 2018.

 

[wholelottared]

@logixx , I promise this is my last question lol. So is it true that Mix gets more hot compared to Cottons? I don't have a thermometer so I can't be sure myself.

 

[logixx]

My go-to cycle is Cottons Cupboard with +1 dryness, since I also find that the standard setting leaves things just a little damp (probably one of many ways to get the A+++ rating).

I can't say for sure that Quick|Mix always runs hotter; the app certainly says it's meant for items not sensitive to higher temps. I ran a load of shirts through that cycle (again on Cupboard +1) and they got up to a temp of 50° (I did check with a forehead thermometer that can also read surface temperatures).

A medium load of heavy cottons on Cotton Extra Dry also reached 50°, while towels using the towels cycle (default settings) reached 65°C. There seems to be not real target temp with these dryers.

The AEG/Electrolux dryers are nice. One thing I'd wish is for them to have a filter in front of the condenser, though.

 

[logixx]

My Mix cycle certainly does not use the fan. One time, as I was drying a large load of towels using this cycle, it got to the point where condensation started to leak from the dryer. Obviously because that little exhaust fan wasn't running.

 

[mrlaundry1011]

I also find my Bosch has no target temp (it’s the serie 6 self cleaning directselect) and the allergy and towels cycle I believe reach over 70. Including timed dry with “low heat”. I also find my fan glitches sometimes and will constantly cycle on and off no matter what cycle or ambient temp, the basic serie 4 HP I used for a few days did the same. They also have a design flaw allowing sand and grit between the drum and front seals, mine scrapes and so did the one in the place I stayed in, I called Bosch out and they said it was my fault and if he didn’t replace the bearing I would have been charged (he didn’t fix the scrapes anyway). I normally use mixed +2 or towels normal or +1 depending on the size of load, however it’s just sat there now as it’s not as efficient as the Beko hybrid next to it (A++ vs A+++) and the Beko reverses and runs cooler, also my T1 runs the coolest and senses the best and keeps much more damp air inside, as well as being A+++

 

[wholelottared]

Thank you everyone for the recent replies! Ugh I started to feel like I made a bad choice with choosing a Bosch dryer, can't believe they don't even know what temperature they are reaching. I could've bought the flagship AEG/Electrolux instead. But it happened at this point haha. Let's hope it serves me for years. If the exchanged dryer comes faulty too (i'm still waiting for it to arive), maybe I can do a refund and go with AEG/Electrolux instead.

About the Miele's, I was actually gonna buy a latest Miele T1 dryer before thinking the Bosch Home Professional, but then I saw on YouTube that recent Miele dryers all have a ticking noise problem because of a sensor, and service was saying them it was normal. That noise sounded to annoying to me so I didn't chose a Miele.

 

[wholelottared]

Also, I just realized that none of us talked about the Easy-Care(Synthetics) program yet haha. One time I tried that program with the default settings with everyday clothes and some things were really damp. Next time, i'll try using Easy-Care(Synthetics) with Cupboard Plus instead of Mix, maybe it might get less hot compared to Mix, hopefully.

Also it sounds like they really did change the programming because on my brand new Home Professional (before they took it for exchange) it was 100% using the fan time to time during the Mix. Weird.

One other weird thing I noticed is that the “Duvet” program (which I acces from the other programs menu) is like a timed warm program which goes for like 3-4 hours. It doesn't even use the sensors. Because when it does it thinks it dried and stops even though the insides didn't try, so they set it up like a timed program I guess.

 

[mrlaundry1011]

Bekos duvet prog is kind of similar, if using for sheets and it’s only one set you have to set dryness to less. Mieles bed linen prog I only use extra dry which can dry sheets and duvets with no problem, Bosch? Yeah no reversing so , everyone says how they’ve improved now but only ONE model branded as BOSCH only reverses, no Siemens or neff etc models reverse still. Their washer dryers are just as bad at drying, sensors stop too early so clothes left damp although their gentle dry setting is only 62-64c which is less than some cycles the heat pumps reach even though WD is condensing. I never use any easy care or minimum iron progs as they’re not meant to dry fully, as polyester and other fabrics may shrink if they are or at least that’s what they say. Yeah mine makes the loud ticking noise but I wouldn’t choose any other, apparently only 66db rated models do it. I wouldn’t go for an AEG simply because of no foam filters, they’re needed, plus I had a A++ 7000 series model which I didn’t like at all

 

[wholelottared]

Okay, thanks @mrlaundry101 . I heard that 64db Miele's do it too, apparently only 62db models don't do it.

So, now I learned that:

Bosch/Siemens = heats too much, doesn't know it's own temperature
Electrolux/AEG: lacks important filters
Miele: makes annoying ticking noise, has smaller drum

Literally why can't we have a perfect dryer? It's like brands aren't even trying hard enough. This is disappointing. I was waiting to buy a dryer for years. Maybe I shouldn't overthink and be happy with my Bosch dryer, I don't know. So far it didn't shrink anything even though apparently it gets hotter, so I guess it would be ok.

 

[maytag85]

Reply #19

All dryer designs have their Achilles heel, sometimes it has to do with the way it’s programmed or the mechanical layout/design. Condenser dryers don’t need a vent but the condenser needs to be cleaned out from time to time or else the efficiency will be choked down. Heat pump dryers are similar to condenser dryers in the way they work but have a refrigeration system in place of the condenser and if there’s a leak in the refrigeration system, it simply will stop working and will have to have someone who’s licensed to work on a refrigeration system due to the complexity. Vented dryers electric and gas aren’t nearly as complex as condenser and heat pump but need a vent to exhaust the warm moist air to the outside and are a bit more expensive to operate but depends on the area you are in. Vented dryers need to have the venting/ductwork cleaned from time to time along with the inside of the dryer itself for optimum efficiency and reliability. Only things that really fail on vented dryers are thermostats, heating elements, and on gas versions it’s the gas valve coils, igniter, flame sensor.

 

[wholelottared]

Reply to #20

Thanks for your reply, but i'm only interested on HeatPump dryers. The other type of dryers aren't even available on Europe anymore, they feel outdated. The problems you talked about depends on the type of the dryer, while the problems I was talking about depended to brands (they are all HeatPumps).

 

[logixx]

I think Miele has a 120 liter drum, AEG is 118 (I think) and Bosch is 112.

As Lucas pointed out: Easy-Care won't dry. Didn't dry fully on my old Siemens condenser, either. I guess you're better or equally well off just using Cottons without +1.

Also: yeah, I think the Duvet cycle is just a timed 3 hrs. program.

One thing I will say is that I have not had major issues with tangling in the Bosch. My neighbor has a 55cm deep Beko that reverses and it's horrible at tangling things. There are a bunch of reversing models here in Germany, now. All of them middle-of-the-line.

If I had to buy a dryer now, I'd probably go for Beko and then I'd purchase the bottom filter separately. At least that way I didn't spend too much money when it breaks. Miele would just be too expensive, if I really went for the "cool" features I'd like (and probably never use ).

The Bosch dryer certainly does get the job done and I haven't had any shrinkage yet... it's just not what I've come to expect having used their washers and dishwashers.

 

[wholelottared]

Reply to #22

Yeah, @logixx . I also never had any tangling in my Bosch dryer (during my 1 month use before they took it to exchange), I think it's because of that weird cone shaped thing on the back of the drum. Maybe that really helps. I think people exaggerate it when they keep saying it balls things, it depends on what you put inside it too, and how you put it. For example if i'm drying large sheets with normal clothes, I fold the sheets before putting it to dryer, and that helps a lot. It gets slowly unfolded during the drying so it doesn't ball/tangle anything.

 

[wholelottared]

Also, I don't think Miele's have 120 liter drums. I can't find any info about it on the web. When I saw them at the shop they were looking way smaller compared to both my Bosch or any AEG/Electrolux. They might have a deeper drum, but their width weren't big at all. And I think width helps more.

 

[logixx]

Miele = 120 liters

It's in their manuals listed under technical data.

 

[foraloysius]

Condenser dryers and heat pump dryers always leave the laundry a bit wet. That's due to the closed system. Most of the time after a few minutes the laundry feels dry. Selecting a higher dryness level may help a bit. I experienced it both with my Miele condenser dryer and the Siemens heat pump dryer I now have.

Tangling bed linens was an issue with my reversing Miele and is also an issue with the Siemens I have now. I guess putting two duvet covers, two pillow covers and two stretch fitted sheets in together doesn't help. I usually dry the load partly in the dryer and then hang the bed linens up to dry. Makes a big difference in regard to wrinkling too.

The temperature inside a heat pump dryer is way lower than in a vented or condenser dryer. Even on the normal temperature setting, shrinking should not be an issue.

 

[wholelottared]

Reply to #25

Damn I'm surprised then, maybe their door is smaller and that's why it made me feel they have a smaller drum. Or as I said maybe they're more depth-focused.

 

[wholelottared]

Reply to #26

Yeah @foraloysius , but if you read the posts in this thread they're saying that Bosch/Siemens dryers reach 60-70C° during normal cycles even though they're Heat Pump dryers and that was what made me worried. A heat pump dryer shouldn't reach these numbers normally.

Also, I saw that you also use one of the never Siemens models, which has an AutoClean system instead of SelfCleaning Condenser (which is like my new Bosch Home Professional). Looks like you were using it since sometime, how is the condenser looking, any signs of clogging or looking dirty? I'm thinking to add the double filter to the door to make even less lints to reach inside the machine.

 

[moon1234]

We have a Miele T1 that has over 5000 hours on it and has been trouble free. The clothes are never overheated and the dryer does have temp control and adjusts based on the dryness of the laundry. The dryer has a de-superheater. Essentially a small radiator that refrigerant is passed through with a fan to remove the excess the heat. As the clothes get dryer the compressor does not run as often and excess heat is removed from the refrigerant.

The Miele dryer DOES NOT make a loud noise like the one in the video above. It has a small set of carbon brushes that ride on the outside of the drum. This is how the sensor that determines the moisture content of the textiles transfers the electrical signal from inside the drum to the outside computer. When the brushes wear down to a certain point the plastic arm that they are connected to starts hitting a spot weld on the drum as it turns. This causes the brushes to “jump” a little as the spot weld passes under the arm. The “knock” heard is just the brushes being pushed back down by the arms attached spring.

In reality the noise is almost inaudible unless your house is virtually silent. I replaced the arm with brushes ONCE on my last Miele dryer when it had around 9000 hours on it. Not due to the “noise” but because the brushes had become so short the dryer was throwing codes saying it could not detect the moisture content of the textiles. My wife had switched to using timed dry to keep the dryer running. So I replaced the brushes and problem solved.

I think you would be happier with a Miele if laundry perfection vs just being dry is what you are looking for.