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Diesel Heater Fix

Manual fuel priming on a diesel heater, without flooding

Updated

Prime only when the fuel line is empty: on a new install or after the tank ran dry. The buttons differ on every controller, so find your panel in the tables below, watch the clear fuel line and stop as soon as fuel reaches the heater inlet. Priming past that point pumps diesel into the burner, and owners who did it got heavy white smoke and no start.

Which controller do you have?

The same number means different faults on different controllers. Match yours to a sketch first. Every controller family has its own priming buttons, and some only accept them in a short window after power is connected.

Not sure? Use the full controller guide

At a glance

What is happeningRunning the dosing pump by hand to fill an empty fuel line before a start
Most common causeA new install, a new tank or line, or a tank that ran dry
Check this firstIdentify your controller, then prime in short bursts while watching the fuel line
EvidenceManuals and owner reports

When do I need to prime the fuel line?

Only when the line between the tank and the heater is empty:

  • on a new install, or after fitting a new tank, pump or fuel line;
  • after the tank ran dry and was refilled.

The Vevor CY manual says to prime before the first start, because otherwise the heater can take over 30 minutes to detect fuel. Manual The T4 manual limits its priming mode to the first installation of a split heater or an empty fuel circuit, and says all-in-one heaters do not need it. Manual Heatport’s EnControl manual says its pumping mode is not for regular starts because of the risk of flooding the combustion chamber. Manual

A heater that has been running does not need priming before each start.

Which buttons prime my controller?

Find your panel first: the controller pages show each one. All of these are done with the heater switched off but powered.

From manuals

Controller Buttons
5-button LCD (Hcalory M98 manual) Hold down and press OK: the screen shows H-oF. Release OK and press up: H-on, and the pump runs. Down or set stops it.
B2010 Press setting and down together: a time such as 020 shows. Setting picks the digit, up and down change the seconds (up to 999). OK starts and stops the pump. Power exits.
Vevor M-button panel (XMZ-D1, XMZ-D2) At first power-on only: hold the down key for 7 s. The pump runs through a fixed 300 s countdown. Power stops it.
Knob LCD (Hcalory HC-A01) During the power-on self-test only: hold the pump key at the lower left until -P- shows. A fixed 300 s countdown runs and ends by itself. No early stop is given.
Vevor CY knob LCD with oil pump key Long-press the oil pump key for two seconds. Release to stop.
Vevor CY single-knob LCD Hold the knob 3 s for engineering mode, turn to Ho and short-press. Short-press again to stop; it stops by itself after 3 minutes.
Vevor CY 5-key LCD (H1 to H6 gears, E-2 to E-10) Press up and down together for 2 s. Release to stop.
Vevor CY 3-key LCD Press power and right together: HoF. Press left: HoN, and pumping starts. Right exits; it exits by itself after 3 minutes.
Vevor CY LED-bar dial Long-press OFF for 2 s. Release to stop.
Liwolf (H1 to H6), with the upgraded remote Long-press gear up and gear down together. Release to stop.
T4 two-knob switch Press the Time knob and the Power knob together until Polr shows and the buzzer sounds. After 80 seconds the pump runs a fixed rapid cycle, then the heater ignites by itself. No early stop is given.
Heatport H2 / H4 EnControl Hold the rotary switch until Polr shows, then release. The pump runs a fixed rapid cycle, then the heater starts by itself. No early stop is given.
Rotary knob with LEDs (Belief, Dieselheat) No priming function is described. See below.

Every row is from the manual named or, for the Vevor rows, from Vevor’s own manual. Manual One caveat on the Vevor M-button row: the key icon did not survive in the copy of the manual read for this page. The down key is how that step was read, and it matches the near-identical step in the Hcalory M98 manual.

Four panels run a fixed priming cycle

The Vevor M-button panel and the Hcalory HC-A01 run a 300 s countdown. The T4 and the Heatport EnControl run about 500 pump pulses and then start the heater by themselves. Vevor’s manual says the power key stops its countdown. The HC-A01, T4 and Heatport manuals give no way to stop early, and Heatport’s warns that this mode can flood the combustion chamber. Use these cycles only on a completely empty line, on a new install or after running dry. Never use them to chase bubbles in a line that already holds fuel.

From owner videos

Controller Buttons
Blue LCD with arrow keys Hold the settings (spanner) button and press the right arrow until H oF shows. Left arrow starts the pump, right arrow stops it, settings returns.
Unbranded H1 to H6 panel Hold up and down together. The pump runs while they are held.

Both rows come from owner videos. Owners No manual was found for the blue panel, and the owner who shows it primes at first power-up. Owners

For the unbranded H1 to H6 panel, three owner videos show up and down held together. Owners That is the same key press the Vevor CY manual gives for its five-key panel with H1 to H6 gears, in the table above. Manual The owners’ panel is probably the same design, though no source confirms it: see the E-2 to E-10 panel page. One owner needed only a few seconds for 1.5 m (about 5 ft) of line, and another says to release quickly to avoid smoke. Owners

On the classic 5-button LCD, owner videos show a pump screen that starts at off, with up to run the pump and down to stop, but the captions do not name the two buttons that open it. Owners One owner in a forum comment describes OK and down, then the up arrow, which matches the Hcalory M98 manual. Owners If that does not work on your panel, it may be a different controller in the same case.

What if my controller has no priming function?

Dieselheat’s guide for its rotary-controlled heaters uses start cycles instead. A start cycle takes about 6 minutes and makes two attempts, then locks out. Reset by removing and refitting the fuse, and start again. The guide says a new or run-dry heater can need up to 6 complete start cycles to purge the line. Manual Resetting is covered on how to reset a locked-out heater.

How do I tell that fuel has arrived?

Fuel tankfuel levelpickupFilterDosing pumpangle: see your manualHeaterfuel lineCheck in order: fuel in tank, pickup below fuel level, filter clear,pump ticking, no air gaps or kinks in the line, joints tight.
Fuel travels from the tank pickup through the filter and the dosing pump to the heater, and priming should stop as soon as fuel reaches the heater. Schematic drawing, not to scale.
  1. Watch the clear fuel line while the pump ticks. Fuel should move toward the heater with each tick.
  2. Stop when fuel reaches the heater’s fuel inlet. The Vevor CY manual says to prime only up to that point. Manual The Hcalory M98 manual says the same and warns that excess fuel causes black smoke. Manual
  3. Start the heater normally.

How long it takes depends on the line. One owner saw about 2 minutes for fuel to reach the pump and 1 more to reach the heater, with 1.2 m (about 4 ft) of line on each side. Owners Use the line, not a stopwatch.

If fuel does not move at all while the pump ticks, priming longer will not help: go to tries to start, then E-10 for the fuel-side checks.

What happens if I prime too long?

Over-priming floods the burner

Once the line is full, every further tick of the pump puts diesel into the burner. A flooded heater blows heavy white smoke and will not light. Prime in short bursts and stop when fuel reaches the heater inlet. On a panel that runs a fixed priming cycle, use it only on an empty line.

The manuals say so directly. The Vevor CY manual says over-priming causes heavy white smoke. Manual Heatport’s DiGiCon manual goes further: it allows priming only with the fuel line physically disconnected from the heater, because otherwise the burner floods and the next start fails with heavy white smoke. Manual

Owners confirm it. Two flooded their heaters this way: Owners

  • One re-primed 5 to 7 times chasing bubbles. Fuel had filled the chamber, and about an ounce drained from the air intake when the unit was tipped.
  • One over-primed because they thought there was air in the line, and found diesel all over the inside.

A third owner reports over-fuelling a heater until flames came out of the exhaust. Owners

Bubbles, or the suspicion of air in the line, were the trigger in the first two cases. Bubbles alone are not a reason to prime again.

If you have already flooded the heater, stop and follow white smoke and no start.

When should I stop and get help?

  • The pump ticks but no fuel moves in the line.
  • The pump does not tick at all in priming mode on the right panel, with the right window.
  • The heater is flooded and still smokes after the steps on the white smoke page.

Related questions

How long should I prime a diesel heater?
Until fuel reaches the heater inlet, and no longer. The time depends on the line: one owner saw about 2 minutes for fuel to reach the pump and 1 more to reach the heater with 1.2 m (about 4 ft) of line on each side, while an owner of an H1 to H6 panel needed only a few seconds for 1.5 m (about 5 ft). Watch the line instead of counting.
The priming buttons do nothing on my controller. Why?
Either the combination is for a different panel, or the window has passed. The Vevor M-button panel accepts priming only at first power-on with the heater off, and the Hcalory HC-A01 knob LCD only during its power-on self-test. On the blue panel the owner who shows the method primes at first power-up.
Does the heater prime itself if I just keep starting it?
On a rotary controller that is the documented method: Dieselheat's guide says a new or run-dry heater can need up to 6 complete start cycles, resetting with the fuse after each lock-out. On other panels the Vevor CY manual warns that without priming the heater can take over 30 minutes to detect fuel.
I over-primed and now it only blows white smoke. What do I do?
Stop priming and stop restarting. The Vevor CY manual's method is to detach the fuel line, start the heater, let it stop by itself, and repeat until there is no smoke before reconnecting. The full sequence of checks is on the white smoke page.

Where to go next

Sources

Everything on this page is compiled from the documents and discussions below. We summarise them in our own words; follow the links for the originals.

  1. Hcalory air heater user manual, M98 (PDF) (cdn.shopify.com)
  2. B2010 controller operating manual V1.2 (PDF) (cdn.shopify.com)
  3. Vevor diesel heater manual, XMZ-D1 / XMZ-D2 (PDF copy) (tuitam.pl)
  4. Hcalory HC-A01 toolbox heater user manual (archived transcription) (web.archive.org)
  5. Vevor diesel heater manual, CY-5001 / CY-5002 / CY-5004 (PDF copy) (xlrzbfnheqpszgtyhdkh.supabase.co)
  6. T4 diesel air heater user manual, Alza import (PDF) (dwn.alza.cz)
  7. Heatport H2 / H4 EnControl user manual v1.00 (PDF) (cdn.shopify.com)
  8. Heatport DiGiCon user manual v1.6 (PDF export) (docs.google.com)
  9. Liwolf parking heater all-in-one manual V1.0 (PDF) (cdn.shopify.com)
  10. Dieselheat: diesel air heater fault finding guide (PDF) (dieselheat.com.au)
  11. Owner video: Chinese Diesel Heater Controller Instructions (Unfastened) (youtube.com)
  12. Owner video: Pairing a remote with the blue diesel heater controller and priming the pump (retrorestore) (youtube.com)
  13. Owner video: Chinese Diesel Heater New Controller Q and As (Mic S) (youtube.com)
  14. Owner video: How To Prime Newer Chinese Diesel Heater (Rusty Rose Adventures) (youtube.com)
  15. Owner video: New/Different/Alternative Chinese Diesel Heater Controller (Grizzly Wears) (youtube.com)
  16. Owner report: OK and down, then the up arrow, on an LCD controller (drive2.ru comments) (drive2.ru)
  17. Owner report: time for the pump to fill a new line (The Grey Nomads forum) (thegreynomads.activeboard.com)
  18. Owner report: burner flooded after priming 5 to 7 times (Reddit r/vandwellers) (reddit.com)
  19. Owner report: over-primed heater, diesel inside the unit (Reddit r/dieselheater) (reddit.com)
  20. Owner report: over-fuelled until flames came out of the exhaust (GoFastCampers forum) (forum.gofastcampers.com)