Pushing Your Button.

What Does this Button Do?

The Ventech LHG (Liquid Heat Generator) is, as we are sure you all know by now, the most innovative, efficient, and rapid supplemental heat source for vehicles and diesel generators on the market today.

For many vehicle applications, the LHG comes in a “ready-to-install” kit that includes everything you need from hoses and electronics to bolts and zip-ties. One of the important elements in MOST vehicle kits is the little green ON/OFF switch.

Your button location and appearance may vary. And probably doesn't include the big, animated arrow.

For diesel trucks (RAM, GM/Chevy, Ford), the green button is often mounted somewhere on the dash; for diesel buses (Bluebird, IC, Thomas Built), the green button is sometimes replaced by a toggle switch on the bus’s control console.

Switch it On. Leave it On.

In either case, our recommendation is and has always been, “Switch it on and leave it on.”

With one very important exception – which we will get to in a minute.

Here is the background. The LHG has its own ECU (Electronic Control Unit) and a number of sensors. The ECU gets its power from an ignition-controlled (accessory on) circuit. That is, when wired correctly, the ECU will receive power when the ignition is on and will not receive power when the ignition is off. The LHG won’t use any power (isn’t on) when the accessories/vehicle is turned off.

An LHG ECU

When on, the ECU (and all the sensors) will determine when the engine coolant and the outside temperature are cold enough to need supplemental heat. At this point, the LHG will be activated, and supplemental heat will be added until the ECU (with all its sensors) determines that supplemental heat is no longer required (at engine operating temperature).

Because the LHG gets “accessory on” power, and because the LHG’s ECU automatically turns the LHG on and off as heating demand changes, it can be left switched on...with one exception.

When to Turn It Off – and Why.

As suggested, there is a time to turn the switch off, and that time is - IN THE SUMMER.

Before we continue, note that the guidance presented here applies to LHG systems installed on diesel vehicles, not LHGs on diesel generators or LHGs on electric buses.

OK, that being made clear, you do want to switch your LHG off during the summer. Why? Because the LHG (on diesel vehicles) is programmed to perform clutch maintenance after a period of inactivity.

Basically, if the LHG has not activated in a while, the ECU will automatically instruct the LHG to “clean the clutch.” If you leave the LHG on when the ambient temperature (outside weather conditions) doesn’t require supplemental heat, unnecessary clutch maintenance can happen dozens of times during warm-season driving.

So, best to turn the switch off when it isn’t cold out.

A quick summary with some extra detail.

The LHG has an ECU that manages activation automatically, so you don’t have to think about it.

1. When the weather will be cold (under 50°F, 10°C), turn the switch on and leave it on.

   
   

2. When the weather will be warm (above 50°F, 10°C), turn the switch off and leave it off.

Pretty simple.