A distinguishing feature of Weishaupt burners is that the control unit (the W-FM combustion manager) doesn't just display a fault as a number or letter code — it shows a plain-text description on its screen. That makes it easier to understand what the fault actually is, but interpreting it correctly still requires understanding Weishaupt's safety chain logic.
How does Weishaupt display a fault?
When a fault occurs, the W-FM combustion manager initiates a controlled shutdown. The control and display unit shows the shutdown behaviour and the diagnosed fault alternately, in plain text. This differs from the approach covered in our general fault code guide, where systems like Siemens LME/LMO communicate purely through blink codes — on Weishaupt equipment, someone able to read the display can usually understand directly what the fault is.
Common fault categories
Flame signal issues
The W-FM monitors the flame via the ionisation electrode. If the flame signal weakens, the combustion manager carries out a controlled shutdown. This falls in the same category covered in our general fault code guide — a fouled electrode, an earthing issue, or a worn electrode are the most common causes.
Low gas pressure — a Weishaupt-specific behaviour
The low gas pressure switch monitors the gas connection pressure. If pressure doesn't reach the level set on the switch, the combustion manager initiates a safety shutdown and starts the "low gas programme." This has a notable characteristic: the waiting time before the next restart attempt doubles after every unsuccessful start. So after several failed attempts in a row, the burner's next retry happens at increasingly longer intervals — this isn't a random delay, it's a deliberate manufacturer design choice.
Air pressure switch and pre-purge issues
As with other brands, the air pressure switch failing to give the correct signal (a fouled intake grille, a faulty switch) can trigger a shutdown during pre-purge or operation.
Extraneous light detection
The W-FM monitors for an unexpected light/flame signal during pre-purge. A leaking gas valve or a faulty photocell can trigger this check.
General symptom-to-cause mapping
| Symptom | Likely cause |
|---|---|
| Screen shows text related to the flame signal | Fouled/worn ionisation electrode, earthing issue |
| "Low gas" programme keeps re-triggering | Insufficient gas supply pressure, incorrect pressure switch setting |
| Shutdown during pre-purge | No signal from the air pressure switch, fouled intake grille |
| Ignition fails, retries | Incorrect electrode gap, weak ignition transformer |
When can you try a reset yourself, and when is service needed?
A single shutdown can be cleared using the control and display unit's reset function. But as emphasised in our fault code guide, if the same fault repeats several times in a row, call for service rather than continuing to reset — particularly with the low gas programme, the lengthening retry delays are a clear sign the problem isn't resolving on its own.
Frequently Asked Questions
How does a Weishaupt burner display a fault?
Unlike many other brands, Weishaupt's W-FM combustion manager displays a fault as a plain-text description on the control and display unit's screen, rather than a purely numeric code.
How does the low gas pressure fault behave on a Weishaupt burner?
When low gas pressure is detected, the "low gas programme" starts, and the wait before the next restart attempt doubles after every unsuccessful start.
Where can you find the full list of Weishaupt fault codes?
Since the full list varies by combustion manager generation and burner series, the exact list is found in your equipment's technical manual or through a Weishaupt authorised service provider.
What should you do about a recurring fault on a Weishaupt burner?
If the same fault keeps recurring, call for service rather than continuing to reset — this is a sign of an underlying technical issue. ---
About Beray Enerji
Beray Enerji is an Istanbul-based burner service company operating across Türkiye, with primary coverage in the Marmara, Thrace and Aegean regions, servicing Weishaupt and all other makes and models. We provide fault diagnosis, combustion setting and flue gas analysis, backed by a technical team with 30 years of field experience. For your Weishaupt burner, contact us on +90 (000) 000 00 00 or at info@berayenerji.com.
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References
- Weishaupt W-FM 100/200 Installation and Operating Instructions (manufacturer technical documentation)
- EN 676 — Automatic forced draught burners for gaseous fuels