Like any diesel mechanical engine – there are certain ways in how to operate this heater in order for it to work successfully. 

If the heater is operated outside of these conditions there is a likelihood for it to not work correctly or at all – this webpage is to help you know how to use our diesel heater correctly and troubleshoot if you are having problems. 


1) Thermostatically Controlled

Your heater controls the temperature of your marquee via a thermostat – much like the heating in your own home. The thermostat is a small grey box with a black dial on it, which will be placed on a wall at chest height in your marquee (it may be hidden under the lining walls)

This thermostat tells the heater to turn off and on automatically and will regulate the marquee to whatever temperature you desire. Please note degrees C are the numbers on the inside circle of the dial.

There is a rocker switch on the back of the heater. This needs to be set to position 2 (II) for it go be on “thermostat mode”. Mode I is continuous heat and that will burn fuel way faster. Our team will leave it on position II and we advise not to change that.

Your thermostat will look like this grey box with a black dial on it.

Placed at chest height fixed to one of the legs of the marquee. It may be hidden under one of the lining walls, placed without 8m of the heater itself.

2) When to Turn Your Heater On

These powerful heaters will heat marquees up to temperature in 10-15 minutes – even during the coldest of winter months. There’s no need to pre heat the marquee hours before guests arrive which again will use up fuel!

It’s advised not to turn the heater on before your event starts (if you’re setting anything up beforehand just put a jumper on!)

These heaters have a limited fuel tank and have enough fuel in them for (8-10 hours depending on usage) .  Running them out of diesel completely can cause issues getting it fired back up again.

3) Switch OFF When Not in Use

The heater has enough fuel in it to run for 8-10 hours. I would advise to not turn the heater on when setting up your marquee in the run up to the event to ensure you have enough diesel to last your event.

Please ensure the heater is powered OFF in the days running up to the event. It has been known for the thermostat to kick in and turn itself on overnight when temperatures hit near freezing and the thermostat is set to zero. We don’t want the heater to run out of fuel before the event!

You can refill it with diesel but sometimes it isn’t a 5 minute process if it’s ran dry. It’s like running a diesel car out of fuel and you get air locks in the system and is not a good thing for the engine.

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4) Turning Your Heater Off when Finished

**VERY IMPORTANT** Please don’t just cut the power off when you are finished with your event and want to turn the heater off.

Set the thermostat to zero – you will hear a fan running for another 90 seconds and then it will switch off completely. This function cools the engine down safety so it isn’t a fire risk as the internal chamber is extremely hot. 

Turning off the power without the 90 second fan cooling prevents this safety process from happening – so please wait until the fan has cooled the engine down to a safe temperature and then switch the power off.

5) Running Out of Diesel

Should the unlikely event that your heater runs out of fuel we may have provided you another jerry can of diesel – if this is used there is a charge of £40 however it does provide you a back up.

This jerry can provides another 6 hours of fuel. Here’s what to do if you need to top up your heater with more fuel.

If you need to obtain more diesel – any diesel from a fuel station will be fine. Red diesel also works.

1) Make sure the heater is POWERED OFF

2) There is a black fuel cap at the bottom of the heater where the black plastic fuel tank is. Please pour the diesel carefully in there without getting anything dirty in there which may block the filters.

3) We would always advise to put a plastic sheet or cardboard underneath the heater when pouring, as diesel can sometimes discolour patios and kills grass. Also wear gloves too. It’s not a corrosive substance but the smell takes a few hand-washes to get rid of!

4) Put the black cap back on and turn power on the heater.

If the heater has run out of fuel completely you may have to refer to resetting the heater below.

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6) Resetting Your Deisel Heater

There is a clear button at the back of the heater which should be green when running operationally – but may flash red if there is a fault.

When the heater runs out of fuel completely it will more than likely need to be reset – this is a simple process.

1) At the back of the heater, where the fan is, is a black panel. There will be a clear plastic button that usually is green when operational. If it needs to be reset it will be flashing red. If the heater runs out of fuel, fill the heater back up with diesel then turn the heater back on and single press the red flashing button.

2) The heater will turn itself on again however running diesel engines until they’re empty usually creates an airlock in the fuel system. The heater may turn itself off quite quickly as it thinks there is still no fuel in the system. Repeat step 1 by single pressing the red button (which might have to be repeated up to 10x times) until the airlock leaves the system and the heater has pulled the fuel through. This may take up to 10 resets to do. So don’t run it out of fuel!

The reset button is on the back of the heater which if it needs to be reset will be flashing red. A single press will reset the heater. If the heater has been run dry of fuel it may need to be reset up to 10 times to push the air lock out of the fuel line.


If you are still having issues with your diesel heater despite following the above steps then please call our emergency mobile contact numbers (Mark – 07969 600033) or (Adam – 07458 048761)