reference · revised november
Unit reference
What we carry parts for, what we can rebuild, and where we will tell you honestly that replacement beats repair. Written for narrowboat owners on the Liverpool Canal Link and the Leeds & Liverpool, not for trade.
Webasto Air Top 2000 / 2000 STC
The most common forced-air unit in the Liverpool docks. Rebuildable almost indefinitely: glow pins, screens, combustion chambers, dosing pumps and controllers are all available. Main enemy is short running at low power, which cokes the chamber.
Eberspächer Airtronic D2 / D4
Strong unit, slightly fussier loom. Most call-outs are flame sensor or overheat sensor faults, plus the familiar white-smoke-then-lock-out caused by a tired fuel pump. Control units can be bench tested at Bold Street.
Mikuni MX / MY series
Well built, parts supply thinner than the German units. We keep burner screens and pumps; chamber replacement depends on availability. Often worth rebuilding once, then planning a swap at the second major failure.
Hurricane and other wet-system boilers
Popular on longer liveaboard boats with radiators and a calorifier. Servicing is as much about the circuit as the burner: pump head, air locks, inhibitor condition and stat placement. We do the whole loop, not just the box.
Refleks and Kabola drip-feed stoves
No electronics, no dosing pump, almost nothing to go wrong — until the flue sools up or the regulator floods. We clean flues, reset the oil regulator, renew gaskets and check the draught. The quietest heat on the cut when set up properly.
Wallas and older air units
We will service and fault-find these, but we are straight with owners: where a controller is obsolete and the chamber is corroded, the money is better spent on a modern unit with a ten-year parts horizon. We will quote both paths.
Common faults
A plain-language map of what we actually find when we open the hatch. Codes vary by manufacturer; the causes rarely do.
- no ignition
- Worn glow pin, airlocked fuel line, or supply voltage sagging under start current
- white smoke
- Over-fuelling from a failing dosing pump, or restricted combustion air intake
- black smoke
- Coked chamber and screen from long low-power running — classic marina fault
- overheat trip
- Blocked ducting, closed outlets, or a dry calorifier loop on wet systems
- flame-out
- Water or diesel bug in the tank, or pick-up sitting in sludge
- loud running
- Detached exhaust lagging, loose skin fitting, or a tired combustion fan bearing
Service intervals
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Every 12 months or 1,000 running hours
Full service for forced-air units on a liveaboard boat. Liverpool winters mean long continuous running, so hours accumulate faster than owners expect.
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Every 24 months for light seasonal use
Boats used at weekends and laid up over winter can stretch to two years, provided the heater is run to full temperature for twenty minutes at least monthly.
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Flue and exhaust check annually
Regardless of unit type. Corrosion in dock air is relentless and a failed exhaust run is a carbon monoxide risk, not just an efficiency problem.
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Fuel sample each autumn
Dip the tank before the cold snap. Finding water in October is a filter change; finding it in January is usually a tow and a day without heat.
Owner checks
Three things you can do before calling us. They solve a surprising share of winter faults and cost nothing.
1. Run it hot, once a month. Twenty minutes at full output burns off the soft carbon that builds up during low-power running. This single habit prevents most coking failures.
2. Check the battery before you blame the heater. A diesel heater draws heavily during glow. Below 10.5 V at the unit it will attempt, fail and lock out — behaviour that looks identical to a dead burner.
3. Walk the exhaust. Run a hand along the exhaust from heater to skin fitting with the unit cold. Loose lagging, soft corrosion or a hot spot near timber all want fixing before the next cold week.
Still stuck? Send the enquiry form or call in at Bold Street 53 with the model number and we will talk it through at the parts desk.