Big news: Laura and I got the keys to our little cottage in the Wicklow Mountains!

We moved in last October, but before we could settle in, there was a long list of issues to address: the wiring, the water system, the heating — the list goes on. For this post, I want to focus on the central heating.

Windhager FireWIN Klassic

The house came with a wood pellet boiler, specifically a Windhager FireWIN Klassic. Windhager boilers aren't very common in Ireland; most houses with pellet systems use Italian brands. Pellet Tech was the only company providing service for these boilers, and at the time, they had only just begun working on them, so their experience was limited.

The boiler was in bad shape. The house had been vacant for over two years, and leaving the boiler idle for that long took its toll. Parts had seized, capacitors were worn out, and more. Here is what I had to do to get it running:

• Control panel: The boiler wouldn't turn on due to a blown diode on the PCB. Replacing the diode fixed it.
• Full service: This involved disassembling the blower motor, cleaning the flue, testing the water pumps, freeing the stuck rotary feeder, and cleaning the PCB and wiring with contact cleaner.
• Configuration changes: It turns out many settings were incorrect. I don’t know if this was done by a previous “technician” or the former owner, but it needed to be addressed. I essentially reset everything to default and tweaked the settings to match my specific installation.
• New motor capacitor: Sometimes capacitors just fail. Even if it hadn't failed yet, replacing it rules out future problems in that area (a suggestion from my brother).

Even after all that work, the machine was still stuck in “Standby” mode. You know what the culprit was in the end? The external temperature sensors. The outdoor temperature was reading 58ºC (incorrect, obviously), so the boiler thought there was no demand for heating. Disconnecting the sensor from the control board finally kicked it into gear.

Documentation

Here are some manuals and technical documents that helped me sort this boiler out:

• FireWIN Installation Instructions
• FireWIN Operating Manual
• MES UML C1 Installation and Operating Instructions
• Digital Operation Module (FB 5210)

I also extracted a few specific wiring schematics, as I found myself constantly referring to them:

• FireWIN Basic Circuit
• UML+ Schematic

Next, I’ll install a new hot water tank sensor (type ZTF 222), as the previous one was removed by the plumber when replacing the tank. I will also be replacing the faulty outdoor temperature sensor (type ZAF 200).