Diesel heater altitude tuning: pump rate per 1,000 ft

Why does my diesel heater smoke and soot up at altitude?

Owners put it down to a fixed fuel dose meeting thinner air, so the mixture goes rich. Owners The Vevor CY manual says its plateau mode reduces the air to fuel ratio to suit the thin air of high altitude. It does not say whether the fuel or the fan is changed. Manual

Owners describe what a rich burn does:

• One owner ran a heater on low for 14 hours above 6,000 ft. It shut down, would not restart and was full of soot. Owners
• One owner at about 10,000 ft says his heater started fine but ran rich until he changed values in the advanced menu. He did not post the values. Owners

Soot from a rich burn ends the same way as soot from any other cause: see soot build-up and the clean burn.

Not every heater needs help. Two owners report unmodified heaters used at 9,000 to 10,000 ft with no changes and no problems. Owners One of them was warned by another member that it would carbon up. Experiences differ, so watch your own heater before changing anything.

Is it really the altitude?

Four owners in one TheSamba thread give first-hand reports. They are four people in a single thread, not four independent threads, and none of this is a rule or a setting to copy. Owners

• A split fuel filter, blamed on altitude. One owner’s 2 kW heater ran for 20 minutes at a camp above 8,000 ft (about 2,440 m), stopped and would not restart for five hours. He assumed it was the altitude. The next day he found the supplied fuel filter had split and was letting air into the fuel line. Once the split filter was out and a new line fitted, the heater worked up to 9,000 ft (about 2,740 m) with no change to its settings. He later used it at 11,000 ft (about 3,350 m) with an aftermarket controller. Owners
• Too rich at home. One owner set his mixture with a shop exhaust analyser and found the stock settings far too rich at his home elevation of 4,800 ft (about 1,460 m). He turns the fuel down again above 7,000 ft (about 2,130 m), and reports a clean exhaust pipe after hundreds of hours. He gave no Hz figures. Owners
• A menu setting by elevation. One owner bought a heater with a high-elevation menu setting and keeps it set for 7,000 ft (about 2,130 m). He judges the burn by whether the exhaust leaves soot on a cold surface. Owners
• Altitude mode on a mismatched heater. One owner’s 2 kW heater had a 5 kW board and a 22 ml pump, and sooted solid within hours. Holding the controller’s Height button for 2 seconds gave about five hours with much less black smoke, which was not a full cure. He gave no elevation. Owners

The first report is the caution to take from this thread: look for an ordinary fault, such as air getting into the fuel line, before blaming altitude.

Does my controller have an altitude, plateau or Alpine mode?

Check this first: it needs no menu and no numbers. Find your panel on the controller pages if you are not sure which one you have.

The first six rows are from manuals. Manual The last row comes from owners: two owner videos of an unbranded H1 to H6 panel show the same key press. Owners That panel is probably the same design as the five-key H1 to H6 panels in the Vevor CY and Liwolf manuals, though no source confirms it. The owners’ key press matches Liwolf’s; the Vevor CY manual enters with set and up instead. See the E-2 to E-10 panel page for what those manuals say.

Gasmate’s manual is the only one with a figure. It says standard operation is for up to 1500 m (about 4,900 ft) above sea level, with high-altitude mode above that. Manual The Vevor CY and Liwolf manuals give no altitude at all. One owner of the H1 to H6 panel suggests Alpine mode above about 2,000 ft. Owners That is one person’s suggestion.

My panel shows an altitude reading. Does it adjust by itself?

Several panels have an altitude item that you can read but not set:

• Vevor M-button panel (XMZ-D1, XMZ-D2): item 007 of the engineering menu. The manual describes no pump or fan tuning. Manual
• Knob LCD (Hcalory HC-A01): query item En06. Manual
• Blue LCD: one owner video shows an altitude page among those the OK button steps through. Owners

No manual says what the heater does with this reading. Owner reports are mixed:

• One owner’s blue panel showed 89.4 m at a place about 550 ft above sea level. Owners
• One owner at 8000 ft had a three-button controller that showed 1 m and offered no tuning. Owners

So a reading on the screen is not proof that the heater is compensating.

How do owners tune the pump rate by hand?

This applies only to panels with a PIN menu, mainly the classic 5-button LCD that shows a Hz figure. How to get in, and what each item does, is on the hidden settings menu. One owner video walks through it for altitude: low pump rate first, then high pump rate, then low and high fan speed. Owners

No manual gives a figure for how much to cut. What the owner sources give:

• 4% per 1,000 ft. One owner cuts the pump setting by 4% for every 1,000 ft above sea level, within the limits of the menu, and says it takes 30 seconds. Owners A second poster relays the same rule from another forum, with a default of 1.6 Hz and a range of 0.8 to 2.5 Hz and the fan left alone. He had not used it himself. Owners
• About 9% per 1,000 m. A third poster states this instead, which is roughly 2.7% per 1,000 ft. No test was reported. Owners
• One owner’s settings. A 5 kW heater at 12,000 ft and minus 8 °F (about minus 22 °C) ran at 2 Hz, and at 1.2 to 1.6 Hz in milder weather: six months of full-time use without problems. Owners

As arithmetic only: at 5,000 ft the 4% rule gives a 20% cut, which takes 1.6 Hz to about 1.3 Hz.

The same owner who uses the 4% rule also runs the heater on high for a couple of minutes before shutdown. Owners

Which controllers cannot be tuned?

• H1 to H6 panel: it has levels, not a Hz figure. One owner tried several codes on its code-entry screen and none opened a settings menu. Owners It does have Alpine mode.
• Vevor M-button panel: the manual’s engineering menu is read-only. Manual One owner of this type of heater describes its menus as locked down. Owners
• B2010: its manual shows no pump-rate, fan-speed or altitude setting. Manual
• Rotary knob controllers: nothing is documented.

One owner got round a controller with no tuning by replacing the controller, main board, remote and harness together with a five-button set, and reports the heater runs better. Owners The controller and the main board have to match, so this is not a plug-in swap.

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

When should I stop adjusting?

• The heater still smokes or soots after the altitude mode is on, or after a modest cut in pump rate. Check the intake, the exhaust and the fuel side before cutting further: see shuts down or will not reach full power.
• The heater is already sooted, like the one that ran 14 hours on low above 6,000 ft. A lower pump rate is a setting for the next burn, not a way to clean the heater: go to the soot page linked above.
• You no longer know the original values.