Heat-pump clothes dryers
rhl_
| Posted in General Questions on
It appears that the big Whirlpool heat pump dryer is now off the market in the USA. Is that right? Are any large size units still actively sold in the USA?
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It doesn't appear so. They still actively list a model for sale in Canada.
Looks like Whirlpool has new models that have a touch panel instead of a cycle control knob. They are listed at Home Depot and AJ Madison. I have owned the original model since March of 2016. It starts at a peak of 2500 W and drops to 1200 for the rest of the cycle. Usage dropped from about 530 kWh to 330 kWh per year for a family of two. It works great, but the drying times are longer (about 2 hours) and it requires periodic cleaning of the interior coils. I did it myself because paying a professional to do it would likely destroy any savings on usage.
https://www.whirlpool.com/laundry/dryers/electric/p.7.4-cu.ft-front-load-heat-pump-dryer-with-intiutitive-touch-controls,-advanced-moisture-sensing.whd560chw.html
https://www.whirlpool.com/laundry/dryers/electric/p.7.4-cu.ft-closet-depth-front-load-heat-pump-dryer-with-intiutitive-touch-controls,-steam-refresh-cycle.whd862chc.html
Woah! This is an absurd level of maintenance! Be honest, is it worth it? I’m presuming they don’t make it easy to take the thing apart..
It is worth it for me because my previous dryer tended to randomly melt clothes that got stuck on the air outlet. An internet search shows this to be a fairly common problem with multiple brands. That never happens with the heat-pump dryer. I used the technical manual to take it apart. Time consuming, but doable. You can find the manual online in multiple locations. Make sure to follow the disassembly instructions to the letter.
There is a design flaw in the model I have, and I suspect it persists in the models for sale now. The filter that is supposed to catch the lint before it gets to the coils doesn't seal completely around the edges. That's what allows lint to get by and gradually clog the coil up. There's a couple of ways to modify the set up to solve this problem, and if you do that when the dryer is new, it may prevent you ever having to take it apart to clean the coils. At the very least it would drastically increase the cleaning interval. Unfortunately, I didn't become aware of the issue until at least a year of use, so I'm going to have to do the disassembly at least once.
Does it involve replacing the rubber seal around the HybridCare filter with something more substantial? Or possibly modifying the "secondary lint assembly bezel"? When you take it apart, make sure to inspect the float switch and reservoir for the drain pump while it is accessible.
Are these two issues truly the same? is the cleaning required because of a flawed lint trap? That sounds like a class action to me..
One solution I envisioned was to build up the rubber seal, or add a gasket on the filter assembly where it mates to the seal. Another was to replace the fixed bug screen "filter" with something capable of catching the lint, or just glue filter media on top of the screen. This would require periodic vacuuming. I might do both, and the new filter would indicate whether or not the gasket fix was working.
The flawed trap is almost certainly the cause of the build-up on the coil heat sinks.
Thomas: How'd you get at the coils to clean them?
By taking the dryer apart using the technical manual. The coils are located inside a sealed box at the bottom right of the machine. If Whirlpool had made that metal screen behind the lint filter removable from the front, the job would be easy. Service techs will sometimes cut the screen from the front. That would certainly void your warranty. I also had to clean the float switch for the condensate pump. When that gets stuck, it causes the dreaded F9E1 error.
I can't vouch for it... but Home Depot has this combo LG wash-heat pump dryer in Canada.
https://www.homedepot.ca/product/lg-electronics-5-0-cu-ft-front-load-all-in-one-electric-washer-dryer-combo-in-white/1000807913
I'm assuming it's a heat pump since it is marketed as ventless.
From the description of the LG combo unit: "Ventless condensing drying system." Condensing dryers are different from heat pump dryers (or you could say that a heat pump dryer is a type of condensing dryer, but if it's described just as "condensing" it's probably not a heat pump dryer), but both are ventless. https://lgwasherdryer.com/difference-heat-pump-dryer-condensing-dryer/
Interesting, I didn't recognize that Whirlpool as a ventless heat pump, because it didn't turn up on a google search for Whirlpool heat pump and it's listed as a type "electric" on Energy Star's website (and there's a huge increase in estimated energy usage from the next highest ventless dryer).
I have a Meile heat pump dryer and it performs very well. I think a large part of that is due to the additional lint filter it has. There is the traditional fine mesh filter that would appear to be fine enough to catch everything. However this dryer also has a sponge like plinth filter, similar to a small engine air filter, and as you can see from the picture it catches quite a bit of fine particles. In terms of maintenance, I get a warning on the screen to clean the filter about every 25 loads or so. To clean it, I simply place it under running water for about a minute and wring it dry. I am amazed with how much actually is washed out, all of what would have otherwise ended up on the coils.
We have had the Whirlpool for several years now and I have a love hate relationship with it. On higher heat settings in particular, it does cause a jump in humidity in the utility room - verified by my hygrometer. However, it helps a lot to run it on extra low heat - I believe the unit doesn't outpace the condensing system in that case, or something along those lines. I also understand from the NEEA study of these units that running it on extra low is the only way to disable the electric resistance, which otherwise kicks in to a degree (ie, hybrid).
Reading this is really irritates me that lint build up inside the unit on the coils. I can see it back there, and I don't have time to deal with that. It can't be good for efficiency.
On the flipside, the unit does provide its own heat source inside the house, since it doesn't vent outside. I do think there is a sweet spot where on extra low, it is operating efficiently and not increasing humidity. We actually have a box fan sitting on top of the unit, which we turn on and run when the dryer is on. This moves the air out of the utility room and into the kitchen and adjacent rooms. Some of you may cringe at this, but despite its funkiness, it is enough heat to actually heat that corner of the house. I have watched the hygrometer and the humidity is ok.
This seems like a very efficient approach. And I see no dust buildup, and I am super sensitive to that.
Anyone successfully upgrade the seal and stop lint from getting to the hvac heat exchangers?