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Blog Housekeeping & Changes

It occurred to me the other day that I’ve been running this blog now for over 10 years! This is the second iteration, as the first was lost in a server crash shortly after it went live. (Wasn’t so good with backups back then!). In that time the traffic to the blog has grown exponentially, who’d have thought that people would actually like reading most of the waffle that comes out of my brain! 😉

2020 Stats
2020 Stats

It seems the global Covid-19 Pandemic actually had an effect on my visitor numbers as well.

At the moment things are becoming a little cluttered on the back end, and there are a few errors that need sorting on the front end – thanks to some of my readers for pointing some of those out!

Site Theming

I’ve also been using the same theme for most of that time, but it’s beginning to show now with many updates over the years, and no updates to the theme code, that I’m going to start having some issues with the next versions of PHP, so this will have to change. This does join up with another project I have going, for a small webshop. The current theme unfortunately isn’t compatible with the most popular WordPress commerce plugins.

Broken Downloads

Thanks again to my readers for catching this one! It seems most of the downloads on the site have become broken, although I’m not sure why. I have changed over the Download plugin, and I am in the process of slowly moving over the shortcodes to the new system, so they will all be operational again.

On-Disk Size

Over the last decade or so of running, this blog has grown massively in size on disk – the usage currently stands at around 80GB. I really do need to reduce this footprint, so some time will have to be taken going through the backend filesystem to prune out any crap.

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Eberspacher D5W ECU Constant Overheat Error

Eberspacher ECU 25 1599 50 00 00
Eberspacher ECU 25 1599 50 00 00

Here’s another Eberspacher control unit, this time from an ancient D5W 5kW water heater. The system in this case is just flaky – sometimes the heater will start without fault & run perfectly, then suddenly will stop working entirely.
The error codes are read on these very old units via an indicator lamp connected to a test terminal. In this case the code was the one for Overheat Shutdown.

Considering this fault occurs when the heater is stone cold, I figured it was either a fault with the sensor itself or the ECU.

Temperature Sensor
Temperature Sensor

The temperature sensor is located on the heat exchanger, right next to the hot water outlet fitting. I’m not sure what the spec is, but it reads exactly 1KΩ at room temperature.

ECU PCB
ECU PCB

The PCB is held into the aluminium can by means of crimps around the edge that lock into the plastic terminal cover. Inserting a screwdriver & expanding the crimps allows the PCB to be slid out.

Casing Crimps
Casing Crimps

The factory date stamp on the microcontroller dates this unit to March 1989 – considerably older than I expected!
Unlike the newer versions that use transistors, this ECU has a bunch of PCB relays to do the high current switching of the water pump motor, fan motor & glowplug.
Overall the board looks to be solidly constructed, with silicone around all the larger components.

ECU PCB Solder Side
ECU PCB Solder Side

Here’s the solder side of the PCB, which has a generous coating of sealant to keep moisture out.

Bad Joint Closeup
Bad Joint Closeup

Looking at the solder joints for the row of relays on the top side of the PCB, it looks like that there’s some dry joints here.
I suspect that years of vibration has taken it’s toll, as the relays are otherwise unsupported. It wouldn’t be possible to use silicone to secure these devices as they are completely open – any sealant would likely stop them from operating.

Resoldered Joints
Resoldered Joints

Using a very hot soldering iron I managed to get the joints to reflow properly, using lots of flux to make sure the conformal coating didn’t interfere with the reflow.