E-08 on a diesel heater: flame out

Why does my heater keep coming up with E-08?

E-08 is the flame-out code on these three controllers. Every manual for these three controllers points at the fuel side first, but each lists something slightly different:

• OnTrack: a blocked fuel circuit or poor fuel supply. Check that the tank is clean and has fuel, check the filter, try a higher setting, and if all of that is fine and there is smoke, replace the glow plug. Manual
• The generic D2/D4 manual: air in the fuel line, or an obstructed line. Manual
• B2010: air or wax in the fuel circuit causing poor supply. Manual
• Vevor XMZ-D1 and XMZ-D2: flame out for lack of fuel, check the tank. Manual
• Hcalory M98: tank short of fuel, pump or fuel quality problem, a fuel line that leaks or carries bubbles, or blocked intake and exhaust pipes. Manual

Owner reports agree, and add detail. Ranked by how many owners confirmed each cause after fixing it:

1. Fuel not arriving (nine owners). A blocked fuel pipe, a pickup that did not reach the bottom of the tank with the filter mounted off upright, air in a long new line, a seized vent valve in the tank cap, a home-made tank with a sealed cap, a tank that had simply run dry, a stock fuel line that was too long, a stock line with bubbles after the pump that was cured by replacing the whole line, and a pump fitted upside down. Owners
2. Burn chamber packed with carbon or burnt out (three owners). One had E-08 after a year: a new pump and new lines made no difference, and cleaning the carbon out of the chamber cleared it. One, who named no code, found the chamber full of loose carbon after a new plug and screen had not helped. One with E-10 found the chamber burnt out inside and replaced it. Owners Two more reports are left out of this count: one owner changed several things at once, and one was seen only as a search excerpt.
3. Loose power connection (two owners). One found a badly crimped positive pin in the main plug, one found the nuts on the power input terminals inside the case had never been tightened. In both, the pump stayed silent with E-08 on screen. Owners
4. Glow plug failed (two owners). One on a heater that had run for years, one where the fan purged and the pump stage never came. Owners

Single reports, so treat them as leads only: one owner reports a loose wire on the temperature sensor, one a faulty heat sensor on a heater that alternated between E-08 and E-10, one an exhaust pipe flooded with unburnt fuel, and one a maximum pump rate set far too low in the settings menu, which gave E-08 only at full power. Owners

Is E-08 the same fault on every controller?

No. On the Hcalory HC-A01 knob LCD the manual lists E-08 as an ignition plug fault: check the plug connection, then the plug, then the main board. Manual See the knob LCD page.

On panels that show E-2 to E-10 with one digit, the manuals disagree about E-8. Vevor’s CY manual prints it as a flame-out. Manual Gasmate lists E-8 twice, once as a failure to start and once as a flameout. Manual Liwolf prints an E-08 row for a stall and a separate E-8 row for a start failure in the same table. Manual If your screen shows one digit after the dash, read the single-digit panel page before using the checks below.

What should I check first when it shows E-08?

Work from the tank towards the heater.

1. Fuel level and pickup. Confirm there is fuel, and that the pickup pipe reaches the bottom of the tank. If the pickup is short or the tank is low, fix that and go to step 5.
2. Tank vent. Loosen the tank cap and try again. If the heater now primes and runs, the tank could not breathe: clean or replace the cap vent. Two owners found exactly this. Owners
3. Watch the line while the pump ticks. Fuel should move towards the heater in steps, without large bubbles. If the pump is silent with E-08 latched, go to step 6. If it ticks but bubbles sit still or only shuffle back and forth, go to step 4.
4. Inspect the whole fuel run. Look for kinks, a cracked or snapped line, loose soft joints and a filter mounted on its side. Check that the pump is not upside down, which one owner found on a new install. Owners For the mounting angle follow your heater’s manual: the generic D2/D4 manual prefers 15-35 degrees. Manual Fix what you find, then go to step 5.
5. Prime the line. Use the controller’s pump-only routine, described in manual fuel priming, and stop as soon as fuel reaches the heater inlet. Over-priming floods the burner and gives heavy white smoke at the next start. Owners Then start normally. If E-08 returns with fuel clearly arriving, carry on.
6. Power connections. Compare the voltage shown on the controller with the voltage at the battery while the heater is starting. If the controller reads much lower, look for a loose or badly crimped terminal in the main plug and on the supply terminals. Owners
7. Combustion air intake and exhaust. Check both pipes are clear, as the Hcalory M98 manual asks. Manual One owner traced E-08 to an exhaust pipe full of unburnt fuel. Another, who had white smoke and named no code, found a pipe that ran uphill and had filled with fuel. Owners
8. Only fails on high? OnTrack suggests trying a higher setting. Manual If it runs on low and drops out on full power, read the pump values in the hidden settings menu before touching anything else.
9. Glow plug and its screen. If fuel arrives and the heater smokes without holding a flame, the OnTrack guide says to replace the glow plug. Manual See cleaning the glow plug and its screen.

How do I clear E-08 once the fault is fixed?

Fix the cause first, then reset. None of the manuals for these three controllers gives a separate reset step for E-08; what each manual says about resetting is in how to reset a locked-out heater. If you disconnect power, let the heater finish cooling down first: the Vevor XMZ manual says it needs 3-5 minutes to stop completely, and Vevor’s CY manual says not to cut power while the heater is hot. Manual Do not keep pressing start without fixing the fuel supply.

When is it time to stop and get help?

If fuel reaches the heater, power is good, both air pipes are clear and a new glow plug changes nothing, the remaining suspects are a carbon-packed burn chamber and the temperature sensor. Clearing the chamber means dismantling the heater and refitting it with a new gasket.

If you are not sure, ask a technician. Opening the combustion chamber goes beyond routine owner maintenance. A mistake here can cause a fuel or exhaust leak. Stop if anything is unclear.

A dosing pump that ticks but moves no fuel with a clear line and a full tank needs replacing. So does a fuel line that is cracked or leaks air at its joints.