There's that annoying 2 minute delay at the end of a wash. Why is this?
A T • February 9, 2020
Well, ultimately, it's to stop you from putting your hand into a washing machine at full spin (very dangerous), but here's Just a brief explanation of how an old-fashioned washing machine door lock works. (One for the technical geeks who might be interested in this sort of thing!)
Most modern washing machines now have an instant door lock so there's no delay in getting the washing out at the end of the cycle. As soon as the machine stops, the door releases.
These locks also have the added advantage that you can usually pause the wash and add items, such as when you find something that you forgot to put in the machine at the beginning.
However, older machines and lower specification washing machines have a lock which stays locked for around 2 minutes. That short time can seem an age when you're waiting to get the washing out.
I just wanted to put up an interesting explanation of how they work.
When you start the appliance on a wash programme, the machine needs to check that the door is closed and it needs to prevent the door from opening during the cycle.
It achieves this by heating a small resistor which bends a bi-metal contact, causing a latch to move into a position which prevents the door from being opened. This movement also causes the live contact to connect with the unconnected pin on the door lock. When this pin becomes live, the machine receives a signal telling it that the door is closed and latched.
On completion of the cycle, power is switched off from the heating resistor, the bi-metal cools down and it springs back into the unlocked position, allowing the door to be opened.
That's the simple explanation, but I've put up some pictures explaining this in greater detail.
There's a real lack of knowledge as to how these work!
Your dishwasher does a pre-wash, and adding detergent for this phase results in a better wash.
A repair set is available for this fault but it's very difficult to fit!
Circuit boards can often be expensive. When a circuit board fails, replacing it can often make a repair uneconomical due to the sometimes high cost of the board. Most appliance repair companies simply order a new board and replace it as they do not repair down to component level. However, whenever possible, I can offer the option of repairing the circuit board by replacing some of the on-board components, or alternatively, they can be sent off for repair. A board repair can cost a fraction of replacing it, saving you a considerable amount of money.
On a previous blog post, I had to strip down a washing machine to get to a 'colour catcher' which had got stuck in the sump hose. I had a call to a washing machine last week which wasn't draining. On switching the machine to drain mode, all I could hear was a quiet hum from the pump, which was trying to run. I tipped the appliance back, drained out the water through the filter and found a 'colour catcher'wrapped around the pump impeller. Removing this rectified the fault. Another example of these useless items causing problems.
Today, I visited a customer where it appeared that the dishwasher was leaking. Clean water was appearing beside a built-in dishwasher on an 'island' in a kitchen. This was a bespoke kitchen, with hand-built units. I couldn't pull out the dishwasher to thoroughly check out the cause due to the way that the fitters had installed it. It was fitted in such a way that the dishwasher could not be removed, as a wooden strut had been fitted across the dishwasher without any visible way of removing it. I was able to get to the back of the dishwasher through the opposite side of the island which had a cupboard under the island sink. It quickly became clear that the fault was not with the appliance itself, but with the pipework supplying it. The dishwasher supply pipework has a fitting that has a compression joint. This had a small bead of water above it which was causing a tiny leak. I'm not a plumber, but I got my grips and a spanner and tried to tighten this up but the nut didn't move at all. That's as far as I was willing to go with it as I had visions of the fitting splitting at full mains water pressure with no way of turning off the supply. I certainly didn't want to risk this so I had to advise the customer that they would need to get a plumber in to rectify the fault.
My first blog post of 2020! Colour catchers. They cause problems! I've been to problems caused by these recent 'innovations' before. I recently went to a job in Kings Langley where the washing machine was failing to drain. On removing the sump hose, a collection of 'colour catchers' was found in the sump hose, stopping the water reaching the drain pump. You will notice from the photos that modern machines now have a ball in the sump hose. These are for saving energy. The ball rises when the appliance fills, sealing off the area beneath the tub. This means that the machine doesn't have to heat the water between the tub and the pump, saving energy! The ball, however, restricts the outflow of water from the drum, and it doesn't take much to collect around it to severely restrict the ability to drain. I really don't believe that these colour catchers actually do anything at all. They seem to change colour, but that isn't necessarily going to stop colours running since the colours will also run elsewhere! My advice, don't waste money buying these things. They may well end up costing you a visit to remove them!
My number one dishwasher cleaning tip for these liquids - Don't put the cleaner in at the start! There are many proprietary dishwasher cleaners on the market which do a reasonable job of cleaning your dishwasher. However, if you don't follow the instructions carefully, you may not be getting a proper clean and may actually be wasting the product. Some of these cleaning products are approaching £5 a time, so it's a lot of money to pay out to then not get the benefit. The problem occurs if you put the cleaner in at the beginning of the cycle. These liquid cleaning products have a wax seal under the cap. When you remove the cap, you place the bottle upside down in the dishwasher and the wax seal keeps the cleaning fluid inside the bottle until the water heats up, the wax then melts and dispenses the cleaning liquid into the dishwasher so that it will circulate round the system for the full duration of the main wash. The idea is that the liquid should dispense after any cold pre-wash and get dispensed when the main (long) wash begins. The longest wash cycle should be used for this procedure. However, the longest cycle usually starts with a short HOT pre-wash. If the cleaner is put in at the beginning of the cycle, the liquid will be dispensed too early so it will only clean briefly during the pre-wash phase before being flushed away (around 10-20 minutes) and won't have had time to do a really thorough clean! A dishwasher cleaner needs to recirculate for a sufficient time to thoroughly clean out the system during the main part of the washing cycle. This comes after the short hot pre-wash and runs for a considerable length of time where the cleaning fluid gets to do a thorough job. The answer to this is to wait for the first part of the cycle (the hot prewash) to complete BEFORE introducing the dishwasher cleaner into the system. This can be achieved by simply waiting approximately 10-20 minutes into the cycle, (by then, it should have completed the pre-wash), or by observing when the pre-wash has finished by listening out for the water to drain before it fills up for the main part of the wash. Then add the cleaning product. (Open the door just a fraction and wait a second for the door latch to detect that the door has been opened and for wash action to stop if it has started washing again.) It's a really simple tip which will mean you're not wasting money on an ineffectual clean! Better still, get a cleaning and descaling powder and place it in the dispenser. The dispenser will open only on the main part of the wash so you won't have to hover around the dishwasher waiting for the first part of the cycle to complete. We can supply professional descaler/cleaning products.
I recently visited a dishwasher where the customer wanted a second opinion on the previous engineer's quote for an expensive part. The engineer had found that the machine was failing to go into wash mode and told the customer that a quite expensive wash motor would be needed. The fault was that the dishwasher was filling up but failing to start washing. Normally it's a failed capacitor on the motor. A cheap and simple fix which is easy to diagnose and shouldn't be hard for an experienced engineer to sort out. On examining the machine, however, I found that the fault did not even require a capacitor! Examination of the loom wires which go under the door and supply electricity to the motor revealed a broken motor wire. The constant opening and closing of the dishwasher door over many years had continually flexed the bunch of wires going under the dishwasher door which continue on to the various components in the base area. Eventually, this had led to the motor supply wire breaking. A simple re-joining of the broken wire restored the dishwasher to full operation without the need for any parts whatsoever! The cost to the customer was just the £59 labour/call-out charge since no actual parts were needed other than a simple wire connector (we don't charge for ancillary or sundry items such as these) and I left the appliance back in full working order. I don't think that the previous engineer was doing anything wrong. I'm sure that he sincerely believed that the motor was faulty. He just failed to do the necessary checks which, if done properly and methodically, would have shown that the motor was not the cause of the fault but the wire supplying power to it!