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FIXED Duet Washer GHW9150PW0 Stops Shortly After Start of Cycle FH Error

greenlawn

Premium Member
Joined
Jun 6, 2022
Messages
2
Location
Canada
Model Number
GHW9150PW0
Brand
Whirlpool
Age
More than 10 years
I wanted to put out a recurring fix for FH error code on my older Whirlpool Duet Washer GHW9150PW0. There are other posts on FH code on this forum as well. The closest to the subject is this one:

https://www.applianceblog.com/mainf...t-load-duet-with-initial-fh-error-code.82571/

Some other related posts:

https://www.applianceblog.com/mainforums/threads/whirlpool-code-fh.50773/
https://www.applianceblog.com/mainf...-whirlpool-duet-washer-getting-fh-code.16763/

First I thought to amend it, but then decided to start a separate thread as my solution is somewhat different. Here is my fix and my version of the root-cause of the problem.

My washer is over 12 years old; the exact age is unknown as it came with the house. The last time I fixed the FH code was 4 years ago in spring 2018. I have no idea if it ever had been fixed before and how many times. I went through an extensive troubleshooting at that time taking apart almost the whole washer until I converged to a tiny reed switch inside the flow meter. It lives on a brown PCB inserted in the flow meter’s white plastic housing:


PCB-01.JPG



PCB-02.JPG



The failing reed switch is a very basic 13.5mm (0.53”) SPST-NO switch. This is a through-hole component, but surface-mounted in an innovative (e.g. unusual/weird/cost-saving/trouble-making etc.) way:


PCB-03-2.jpg



The photo above is of my fix from 2018. If interested on how a reed switch works, here is a very nice and detail description:

https://www.explainthatstuff.com/howreedswitcheswork.html

The spec of the original switch cannot be determined as there was no marking on the tiny glass housing. The one I used as a replacement in 2018 was 13.5mm (0.53”) SPST-NO 0.5A@100VDC. There are a few places where you can find reed switches online:

https://www.allelectronics.com/item/rsw-41/dry-reed-switch/1.html

https://www.jameco.com/z/MKA-14103-...-Single-Throw-0-5-Amp-100-Volt-DC_171872.html

https://shop.sayal.com/products/sqr-1125?_pos=4&_sid=b1035804c&_ss=r

Reed switches are known to last forever, unless… The “unless” made me think on its second and fast (only 4 years!!!) failure. A reed switch has two ferromagnetic blades in a glass vial filled with an inert gas and sealed on both ends. Both glass and the seal are extremely fragile. Caution must be taken not to disturb the seal during soldering, and now I’d say during operation as well.

Now, let’s take a closer look at the Whirlpool’s PCB on the above photo. The leads of the switch are straight and not 90 deg bent as it would be in a through-hole mount. The ends are constrained to a surface of a fiberglass substrate by two solder blobs. Now Imagine this system exposed to heat (both transfer and radiant) from the flow meter and hot water hoses. The metal leads will expand/contract faster than the fiberglass and the glass vial resulting in undesirable strain on the seal. The higher the temperature is, the higher the destructive load. This is a thermal expansion 101. You can also throw vibration to the mix as the hoses holding the flow meter vibrate at a high frequency during wash cycle.

By interesting coincidence, the only change that happened to my washer in the past 4 years was adding a new [very] hot water line that bypassed the mixing valve. As a result, the switch ended up under a higher thermal load, which probably cracked the seal faster. So far the failure is explained.

How did I alleviate it this time? With a basic thermal expansion compensator. This is a very scientific term for simple loops as on the photo below. Had the switch been mounted as designed (e.g. through holes with 90 deg bent leads), the needed loops would have been already there by default. Since it was not, some manual filigree was necessary:

PCB-04.JPG



Time will tell if this lasts. The only word of caution: if you happen to follow this solution, please use 2 mini-pliers (or better sharp nose tweezers) for bending and make sure not to disturb the seal. The damage will not be visible, just the switch will fail fast. Also keep in mind that traces delaminate bit-by-bit after each rework. Eventually the PCB will need a replacement, but do I not know if it is possible to get it. If anyone has a link where to buy it, please post.

At last, I have a word for Wirlpool engineers (if any of those would ever read this at all): Please, use electronic components as designed: a surface-mount as a surface-mount and a through-hole as a through hole. Spec violation is not innovation, but hidden defects and frustration to customers. Thank you.
 
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