About 4 years ago we bought a pair of new appliances for the house, a matching HotPoint washing machine and dryer set. As of last week we no longer have either of them, but it did teach me some thing about appliances that I wish I'd known before buying them.
The washing machine was unremarkable apart from the fact it was a large 10KG machine however it completely failed whenever you got anywhere close to fully loading the machine. I believe the problem was while the drum got larger there was less space for a counter-weight and as soon as a large load started throwing its weight around the machine became unstable and it would detect that movement and cancel the wash. It also regularly complained about the water pressure (according to the manual) which is never a problem at my house. Eventually the power supply failed and the insurance company sent a repairman who replaced the power module, he didn't do a very thorough job though and after leaving the problems with the water supply error got even worse failing consistently at the same stage of certain wash programmes. The insurance failed to respond to this problem quickly enough and eventually wrote off the machine and we replaced it with a Zanussi branded model, this time with a less optimistic maximum load of 8KG and this new machine hasn't missed a beat since, we're much happier with it.
As I hate contributing to landfill and had nothing to lose, I opened up the old washing machine and found near the new power supply a blue wire has snapped, tracing this wire it lead to one of the two inlet valves. I believe the reason for two is that one is for fast flow and one for slow flow and it seems that when the slow valve was called upon it failed because of the broken wire. I think this was actually faulty from the factory but the later repair fully snapped the wire that was barely hanging on. The fix was easy, I rejoined the wires and crimped them together securely and tied it down so it would not move again. The programmes then completed fine and we sold that machine on. As far as I know the new own has been very happy with it.
The tumble dryer was also a large unit that would take 9KG of washing, though this was never a problem with it. It was our first "heat pump" tumble dryer, which operates quite differently to the vented and condensing models we've had previously. Early on I tried to install the appliance in the garage as there was no space in our kitchen but as it turned out, it was not suitable for these types of dryers. They operate like a refridgerator and their efficiency sharply drops off as the ambient temperature falls below 14C. If I had known this when buying it then I would've decided against it but they don't make nearly enough noise about the limitations of the technology and since most people around here use their tumble dryers in their garages I'm sure I'm not the only one that fell foul of this.
Eventually I made room in the kitchen for it by removing the old under-counter freezer and ran it there ever since but after 18 months it stopped working again. This time I called out the insurance and they sent an engineer who had strong opinions on heat pump dryers that seemed to be a common theme as time when on. The problem this time is a build up a fluff, normally on a condensing unit you can remove fluff from a filter and occasionally you also remove the condensing unit and give that a good clean too and away you go. On heat pump units however, the heat pump runs through the condensing unit so it is not removable. To compensate for this our model had a two stage filter, what didn't get caught by the first filter got caught by the second...\~98% of the time. Of course it's not perfect so over time fluff builds up on the condensing unit and restricts the air flow eventually causing failure.
The repair is not easy, I watched with interest as the first engineer dismantled the machine in order to vacuum it out throroughly and re-assembled it again. This did work and the machine was back on it's feet again but I knew in time we would be back here with the same problem again.
This happened two weeks ago when the machine stopped working again after another 18 months or so, and after some words with the insurance about the problems with this machine it was written off and we replaced it with a traditional condenser dryer from Beko, which so far so good. I'm familiar with condensing dryers so I know how they work and what can go wrong so I'm condident it'll last a long time but I wanted to understand more about how the heat pump unit failed so, with nothing to lose, I went ahead and took it apart.
Disassembly was not as hard as I expected, remove the top, the side panels and you can get access to most of it. There was a significant amount of fluff inside the machine which I vacuumed out first but the actual system itself is in a sealed duct at the bottom of the machine so I needed to remove the drum to access it. Once the drum was out I was able to remove the lid from the duct to inspect the insides. I seemed the last engineer in there wasn't very careful and the duct was badly damaged in places which probably lead to a lot of the fluff escaping inside the machine, before re-assembly I did take some time to fix some of these cracks with duct tape and minimise the future fire risk.
Inside the duct there are two heat exchangers, both are connected to the heat pump so the first is the cold side where moist air is condensed into water that collects in the sump to be pumped upto the collection tank at the top. The air then passes through the hot side which heats it back up again before it's sucked up into the drum again. At the back of the hot side there was a significant build up of damp fluff about the side of a fist so all off that needed removing. It wasn't as bad as I was expecting but it was clearly bad enough to stop the machine working, I think because it held onto so much moisture that the air was already damp when it entered the drum limiting what it could do in there in terms of drying some actual clothes!
I cleaned out as much as I could and removed as much excess water as I could with some paper towels. Eventually I re-assembled the machine and checked it still worked, it did! I then decided I would run it was for a while without anything in it. After an hour was up I checked the water collection tank and it was a lot fuller than I expected! I poured it out and measured 200ml of water, from an empty machine! I them vacuumed the condensing unit that was now clearly a lot dryer than before and this did seem to help remove some bits of fluff that was previously stuck in there due to being damp.
image above: The dismantled tumble dryer. Red square - hot heat exchanger. Yellow square - cold heat exchanger. Green oval - heat pump. Blue oval - motor. Red oval - start capacitor (dangerous!). White oval - mass of damp fluff (mostly obscured).
I think its probably a good idea to do these empty runs now and again just to dry the machine out to keep the system in good condition, whether than would work long term is hard to say but trying to vacuum out the condensors while there is still a lot of damp fluff in there is an exercise in futility.
None of this is an issue for me though as I'm back onto a condensor model, and I'll be selling this one on, but in future it might be harder to get dryers than aren't heat-pump based. They are more efficient, but they do have limitations, such as their operating environment. They also suffer from a design flaw that makes maintenance by the user almost impossible long term, no doubt a lot of machines have been thrown out due to repairable faults and that's worrying to think about from an environmental perspective. I suspect the manufacturers don't see a short life span as much of a big deal and won't be in any rush to fix it.