Introducing the eVAP Glowworm, an electrically powered, thermo-switch controlled, fuel pre-heater for single or twin tank conversions.

Features: precision engineered heater 3 independent heating elements total peak power available over 700W normal running power less than 250W preset twin thermo-switched control¹ automatic overheat cut-out fuse protected

Suitability: The eVAP Glowworm has been designed for installation as a fuel pre-heater in diesel engined cars up to around 3 litres, including direct and indirect injection and turbo-charged engines. It has not yet been tested with common rail injection and is not recommended for these at this stage. Correctly installed it will allow the use of waste vegetable oil (WVO), standard vegetable oil (SVO), biodiesel and fossil diesel in almost any combination².

In single tank installations, the eVAP Glowworm is normally installed immediately before the fuel filter, as close to the fuel injector pump as possible. The unit is simple to install, having just 3 attached wires; permanent earth, permanent live and an ignition switched live; fuel flows in and out of the heater via 2 hose connectors.

In twin-tank installations, the eVAP Glowworm can be installed as the primary (or only) heat exchanger, following your twin tank system instructions, or as an additional pre-heater fitted between the coolant heat exchanger and the fuel filter.  Fuel from both tanks will normally pass through the heater(s).

The three ignition controlled heating elements run up to peak power of around 700 Watts in just a few seconds, immediately heating the fuel already inside the heater.  In single tank confguration, the engine will always be started on the cold fuel already in the fuel system, but this is replaced within seconds by hot oil from the Glowworm. In twin tank configuration, the engine is started on the diesel which is heated inside Glowworm.

Within seconds, the power will drop to below 400 Watts, producing a steady flow of hot fuel. This hot fuel initially passes on some heat to the fuel pipes and injector pump and creates a buffer store inside the fuel filter, but once warm, the fuel will continue to rise towards its pre-set temperature. In twin tank configuration the main tank can be selected often in as little as one or two minutes.

Two thermo-switches are mounted on the heater block, both of which are pre-set to different temperatures.  As the block temperature rises, the first thermo-switch will disengage a single element, leaving the other two running.  As the heater block temperature rises further, so the remaining two heater elements will also disengage.  As the block cools, two elements will be re-engaged, and if they can't maintain temperature, the third element will also re-engage. As the fuel coming from the tank rises in temperature, so Glowworm will consume less and less electricity, rarely rising above 200 watts, and regularly dropping to zero when all three heating elements are disengaged.

All the components and wiring are securely housed within a solid steel enclosure.

The twin thermo-switches modulate the three heater elements to maintain optimal fuel temperature with minimum electrical input.

¹ The eVAP Glowworm is precision engineered and designed to operate normally above 50°C, being the minimum temperature achieved by most coolant heat exchangers. The actual temperature achieved will depend on, amongst other things, the engine size, the specific location of the Glowworm in the fuel system, the fuel flow rate, the filter capacity and the temperature of the incoming oil.
² Many people will choose to operate a single tank system using 100% WVO.  To ease starting, particularly in the winter, most people will prefer to add 10% diesel to each tankful, all year round, increasing to maybe 25% to act as an anti-freeze in colder winters.