Knox Krypton Fault 01 — Fan Is Locked (Cooling Fan Has Stopped)

What it means: The inverter's cooling fan is not turning. Knox Krypton hybrids are rebadged Voltronic Power InfiniSolar units — an identification that comes from retailer listings and an exact specification match, never from Knox itself — and the InfiniSolar V IV fault table gives code 01 as "Fan is locked", with the troubleshooting table calling it a "Fan fault" and giving exactly one instruction — "Replace the fan." Watch how the icon behaves, because 01 exists twice. Flashing, it is a warning and the unit is still running. Solid with the red fault light on, it is a fault and the inverter has stopped. Either way the machine has told you it can no longer move heat out of itself, which in a Pakistani summer is the beginning of a chain that ends in fault 02.

Why does Knox show 01?

• Dust packed into the fan hub and bearing — by a wide margin the most common cause in Pakistan
• The anti-dust kit's air filter foam clogged solid, so the fan is turning against a blocked path
• A worn fan bearing that has seized, usually after several summers of continuous running
• A disconnected or chafed fan lead inside the unit
• A failed fan-speed sensor, where the fan turns but the inverter cannot see it turning

The Pakistan factor

Dust is the single biggest killer of Knox inverters in Punjab and Sindh, and code 01 is how it announces itself. The InfiniSolar design acknowledges this directly — every unit ships with an anti-dust kit and the manual asks for the filter foam to be cleaned monthly, which is advice almost nobody in Pakistan follows until the fan has already seized. Wheat-harvest dust, construction dust in a new housing scheme, and a store-room installation next to an open window will pack a fan hub solid inside one season. Two local habits make it worse. The first is mounting the inverter in a sealed cupboard or a closed store room to keep it out of sight, which turns a cooling problem into a thermal one. The second is cleaning the heatsink with a wet cloth or a hosepipe — use dry compressed air only, and never spray water anywhere near the case. One caution on identification. The Knox range now spans several generations, from the LCD-and-buttons Krypton 5600 to the 7-inch touchscreen Krypton 9055, and the newer touchscreen models are not guaranteed to use the same code table. Check the manual that came in your box before acting on a repair; if your dealer cannot produce it, that tells you something about the dealer.

How to fix it

1. Safe for a homeowner — look and listen first. Is the fan visibly still? Is the icon flashing or solid? A flashing 01 while the unit still runs is a warning and buys you a little time; a solid 01 with output stopped does not.
2. Safe for a homeowner — clear the space around the inverter before anything else. Cardboard boxes, curtains, a cupboard door, a shelf 100 mm above the case, or a battery bank stacked underneath will all starve the intake, and the fan working against that is what kills it.
3. Safe for a homeowner, with the unit fully powered down — clean the anti-dust kit. The InfiniSolar manual treats this as owner maintenance and asks for it every month. Switch off the AC output breaker, then the PV isolator, then the battery breaker, and give it a few minutes to settle. Then remove the screws on the top of the inverter, lift off the dustproof case, take out the air filter foam, clean the foam and the case, and re-assemble.
4. That is where the owner's job ends. Do not remove the front cover, do not reach inside to spin the fan by hand, and do not power the unit up with the case open. The DC bus capacitors behind that cover hold a lethal charge after shutdown and they do not care that the isolators are off. Neither InfiniSolar manual publishes a safe discharge time, so treat no waiting period as making the inside of the unit safe to touch — the manual's own safety page says turning the unit off does not reduce the shock risk.
5. Do not run the inverter with a locked fan because it "still works". The manual's remedy is to replace the fan, not to tolerate it. Every hour you run without cooling cooks the capacitors and the power stage, and the repair grows from a fan to a board.
6. Qualified installer or Knox service, from here. Fan replacement means opening an inverter and is a service action. Ask for the anti-dust kit to be checked and the filter foam replaced at the same visit, and ask whether the siting can be improved while the engineer is standing in front of it.